What! Another 142 Project Car?

[142 Guy]

In a separate post I noted that while rechecking valve clearances, I discovered I had a leaking valve cover gasket. Oil was drooling out the back of the cover and down the back of the engine. Its one of the IPD heavy nitrile rubber gaskets so I was a bit surprised. I removed the cover and gasket and applied RTV to both surfaces of the gasket and reinstalled. All I managed to do was relocate the location of the leak. I ended up with oil running down the engine coating the distributor and sparkplugs (it was not a small leak). Upon re removal, I discovered that I must have got a little keen with tightening the hold down screws as I managed to squish the gasket out from under the mating surface on the alloy valve cover. I cleaned all the RTV off of the gasket, cover and head surfaces. This time I used some Permatex ultimate gasket maker which definitely has a higher tack than the RTV. I applied the gasket compound to the valve cover, positioned the gasket on the cover and then let it set up overnight. The next day I applied a thin bead of the compound to the gasket surface that mates with the head and installed the cover, tightening the screws just enough to hold the cover in place. After letting it set for a couple of hours, I did a final tightening of the screws, this time making sure that I did not go overboard and squish the gasket out of place. So far, so good. No oil leaks.

I had acquired a bunch of nicks and scrapes in the painted alloy valve cover so I decided to clean up the appearance with a repaint. I didn't have any of the heat resistant red that I originally used on the engine; but I did have some of the silver caliper paint that I had used on the intake manifold and some other parts, so I just used that. I am a little undecided as to whether I like the red or silver better. The silver definitely looks more like the stock engine. I will post a picture when I get a chance. Maybe at some point I will get the cover powder coated for durability if I can make up my mind on the color.

I have been doing more tuning. Most of my tuning has been focused on getting good starting. Particularly hot restarts. However, Sunday evening the temperatures took a big plunge (thank-you disappearing jet stream!) and cold starts have become an issue. Previously, on cold start I would get an instant start and then die, so cranking pulse widths were not a problem and I had spent time getting the after start enrichment adjusted. Yesterday and today, the engine coolant temperature prior to start was around 2 C and I was having trouble getting the engine to fire quickly so I have been upping the cold cranking pulse widths. The cold starting has improved; however, its a slow process because once the engine has started you are no longer dealing with a truly cold engine and have to wait until the coolant returns to ambient before doing your next test. Also, as the temperature warms up during the day you don't get the same cold start conditions, so I really only get one test each day. The good / bad news is that this lousy weather is around for a couple of days. Tomorrow am the temps are supposed to drop down to about -3 C so I should get a chance to check out a new test point. Once the engine gets started, the after start enrichment seems to be pretty good as you don't have to do any fiddling with the throttle to keep the engine running.

I seem to have got my idle stabilized a bit. It now seems to wander between about 860 rpm and 900 rpm. You don't notice this on the dash tach; but, you can see it on the display in Tuner Studio when the laptop is hooked up to the MS. My manifold air pressure still seems to be stuck around 65 kPA at idle which strikes me as high; but, everything seems to be running pretty well so ......?

I have been doing more driving around. With the full tank of gas the issue with the noisy fuel pressure reg and AFR swings has not re emerged so I think that it was just a fuel starvation issue due to a low tank. I have not done any tuning on the right side of the VE table because I have been reluctant to do any full throttle acceleration runs or higher speed runs because I do not have a proper wheel alignment. The car was reassembled without any shims and a 'looks like both front wheels are pointed in the same direction' toe-in adjustment. I have had the car up to 80 kph and given the lack of a proper wheel alignment, the car doesn't do anything bad. It certainly has lots of camber (no shims at all) and probably has lots of toe in. I want to get a proper alignment before doing the high speed tuning and I have put off the alignment because I wanted to make sure I had a car that was reliable when it came to starting and just driving around at low speeds. I could just see taking the car to the alignment shop and having them not be able to re start the car to get it in or some other problem emerging.

[142 Guy]

While driving around, I noticed that my dash voltmeter was consistently reading around 12.5 volts if I had my headlights on with any other accessories. This puzzled me a bit as I had set the voltage regulator to deliver around 14 volts no load and about 13.6 volts with the headlights, heater fan and rear window defroster switched on (at about 3000 rpm). I had set the regulator measuring the voltage at the distribution block on the left front inner fender. I decided to recheck the voltage regulator.

My multimeter showed that under load, I had about 13.5 volts on the distribution block; but, the dash voltmeter was only reading around 12.3 volts. My initial reaction was that the dash voltmeter was out of calibration, so I went to check by measuring the voltage on the fuse panel. Depending on which fuse I checked, I got voltages around 12.3 – 12.5 volts. I confirmed this by measuring the voltage on the + terminal of the ignition coil which was about 12.1 volts with the voltage on the distribution block at 13.6 volts. I am getting up to a 1.5 volt drop (depending on where I measure the voltage) through the car wiring.

The good news about this is that since my battery is connected directly to the distribution block, it is getting a good charging voltage despite what the voltmeter is saying. The down side is that my dash voltmeter is slightly compromised as a useful measurement instrument and the performance of my lighting is reduced by the lower voltages.

Short of rewiring the car, I gave some thought to what sort of quick remedies I could implement. The three big electrical loads in the stock 142 are the lighting, the interior heater fan and the rear defroster. The rear defroster is supplied directly off of the power distribution block through its own relay so it does not contribute to voltage drop on the rest of the internal car wiring. The lighting, in particular the headlights are probably the easiest thing to improve. The circuit for the headlights runs from the distribution block, to the ignition switch, then to the headlight switch then to the headlight dipper relay. The headlights are connected to the dipper relay. It is incredibly easy to add two relays so that the current associated with the headlight filaments (about 10 amps combined) by passes all this wiring. I simply added two automotive relays, one for the low beams and one for the high beams that are controlled by the output of the dipper relay. Each relay was about $3 if you buy it from an electronics wholesaler (about $10 - $12 if you get it from an auto store).

I mounted the two new relays directly beside the headlight dipper relay which minimized the need to do wiring modifications and made it easily reversible if I chose. I pulled the wires to the high and low beam filaments off of the dipper relay and connected tem to terminal 87 of the respective new relays. For the high beam I had to add a very short jumper, about 5 cm, because the existing wire was not long enough to reach the new relay. I then added a short jumper from terminal 85 of each new relay back to the respective high and low beam terminals on the dipper relay. Terminal 86 of both relays is grounded. I added an external weather tight fuse enclosure to supply fused power directly to the headlights. The supply from the fuse is connected to terminal 30 of both relays. With this arrangement, the current in the wiring internal to the car is now reduced to the control current on the relays (probably about .05 amps) as opposed to the former value of around 10 amp. This has reduced the voltage drop in the internal wiring by about 0.7 volts under full load. Also, the voltage at the headlight bulb terminal is now about 13.3 volts instead of slightly less than 12 volts previously. This results in an approximate 20% increase in the effective wattage of the headlights. The wiring path from the distribution block to the left headlight is now about 2 ft long as opposed to around 15 ft long previously. The headlights also now have a fuse that can blow if there is a short in the wiring. The existing headlight wiring for the 140 is unfused which means that if you get a short, you have to melt something before the short clears!

The photo below shows the installation for the external headlight relays. The low beam headlight relay is directly beside the existing dipper relay and the high beam headlight relay is next to it. The fuse for the relays is that black blob with the orange wires mounted on the end of the relay holder. I used the 3M style insulated spade crimp connectors for all of my terminations and sealed each termination with heat shrink tubing. Total cost of the installation including relays, fuse holder, crimp connectors and the heat shrink was less than $15. If I wanted to, it would take me about 5 – 10 minutes to remove the relays and return to stock (except for the extra mounting holes for the relays).



While I was fiddling around with the headlight relays, I decided to add in some daylight running lights. This is not a regulatory requirement given the age of my car; however, it has been a requirement for all new cars in Canada since about 1987. Since DRLs are so ubiquitous now, I have noticed that if you don’t have DRLs, people seem to make the mental connection that the car is not running, or they just don’t notice you. Anyway, it was an easy add in for me since I have the Cibie City lights. I added a relay which is switched on through an OR gate. Turning the ignition switch on or turning the headlight switch to the park or headlights position will switch the City lights on. The City lights are supplied through the same external fuse as the headlights. The DRL relay is the third relay on the right side of the dipper relay in the above photo. The City lamp bulbs are a small bayonet style bulb in the base of the headlight. I used some daylight style LED bulbs in the City lamps which are quite bright and are quite low in power consumption. The photo below shows the headlights with the City LIGHTS / DRLs switched on.

[True142]

I really like the lights and the wiring mod. Will have to put this on my list of future upgrades. Where did you get the Cibie lights?

[142 Guy]

Oops - my error. The headlamps are Hella City lamps, not Cibie. I was originally shopping for Cibie; but, the Hella were significantly lower in cost. As far as I can determine, the light pattern is just as good as the Cibie.

I got them from Susquehanna Motorsports. They had the best price I could find and good service. One of the headlights shipped was missing the sealing rubber boot in the package. After contacting them, they shipped a replacement boot out without any grief!

[142 Guy]

I have been spending some time trying to improve my engine start-up. The engine is not difficult to start, it is just that it does not start up instantly like a modern car (which may be unrealistic) and sometimes it goes through a transition of really rough running before coming to a steady idle. Whatever the amalgam of problems was that caused my previous high idle speed seem to have been dealt with. I can now get the idle down as low as 700 RPM, albeit running fairly roughly. I still have a slight hunting of the idle speed. You don’t particularly notice it on the dash tachometer; but, you can see it on the Tuner Studio display. It is probably about +/- 30 RPM.

At around 900 RPM the engine is fairly smooth with just the odd spasm every once in a while. It is a bit of a mystery as to what causes those spasms. I assume that they are a single misfire; but I am a little unclear as to what might be causing the misfire. It is not a sustained misfire because the AFR does not change materially when the event occurs. The sparkplugs have been through a bit with all of the tuning I have been doing so I think a new set may be in order to see if it helps.

I have noticed that following restart on a hot engine, the AFR goes very low (down to 10 or so) and then continues to run lower than it would be at the same engine speed when the engine is cooler (no EGO correction at idle for now). When I correct the Ve table to give AFRs that are in the 13.5 - 14 range at idle on the hot engine, I find that when I do a cold start with these Ve settings, I am running leaner than I want which makes cold starts a little more of a problem. As the engine gets hot, the AFRs creep down to where I would like them (13.5 – 14) for idle.

My initial thought was that my fuel pressure regulator was operating poorly; however, a number of retests of the pressure suggest that it is operating correctly. The one thing that I have noticed is that at idle, the fuel pressure is constantly fluctuating about 2 – 3 psi. I believe that the regulator is having problems maintaining a constant pressure with the sporadic fuel flow at idle. The pressure smoothens out if you speed up the engine. I don’t know whether this fluctuation is influencing my idle performance. I may in the future try switching from 2 squirts to 4 squirts on the injectors to see if this helps with the fuel pressure. For now, I am leaving it at 2 squirts alternating.

Having at least temporarily ruled out fuel pressure as the source of my lean / rich restart issue, I gave some thought to the location of the Djet intake air temperature sensor I am using with the Megasquirt. The sensor is located right up front next to the cold air intake, so is measuring a temperature that is closer to ambient. Megasquirt uses the air temperature along with the manifold air pressure to estimate the mass of air entering the cylinders via the ideal gas law equation ( n = PV/RT where n is mole mass of the gas and P is pressure and T is temperature). On a cold start, ambient air temperature and the air temperature in the intake manifold will essentially be identical. However, once the engine is up to temperature, the intake manifold temperature will be higher than ambient. If Megasquirt is using the lower ambient air temperature to calculate the air mass entering the engine, it will be calculating a higher mass of air than is actually entering the engine based on the manifold air temperature. This will result in more fuel being injected than is required since there will be a lower mass of air entering the engine (based upon the actual manifold air temperature). This could explain why the tune that would produce my desired AFRs on a cooler engine would start running rich following a hot restart. The magnitude of this problem will depend on the temperature skew between the front air temperature sensor and the manifold air temperature.

I decided to carry out a little experiment using a Fluke digital VOM with an external thermocouple probe. Since this was to be an idle speed test only, I disconnected the vacuum line to the brake servo and fabricated a little adaptor to allow me to insert the thermocouple into the intake manifold and seal it off. I secured the probe so that it was suspended approximately in the center of the manifold, not touching any metal parts. Before doing this, I confirmed that the Djet sensor were both reading the same ambient air temperature. The test started on a slightly warm engine which is why the manifold temp was above ambient. As soon as the engine started up the manifold temp temporarily dropped as cool outside air entered. I used the Tuner Studio display to monitor the Djet temperature sensor.







The results of the test are as follows:



During engine warm up, the Djet sensor temperature did not move much until the cooling fan started up at which point it jumped about 13 deg C. I have seen this before and I believe that this is primarily due to backwash from my pusher cooling fan set up. I think that it is an effect that is evident at standstill and probably disappears completely once the car is under way. I let the engine idle for about 15 minutes and the maximum manifold air temperature stabilized at 46.4 C for a temperature skew of 12.9 C between the D jet sensor and the manifold thermocouple.

During the test, I lowered the RPM threshold on the EGO correction so that it would operate at idle speed. In the Tuner Studio display you can see that the engine speed has increased to about 1000 rpm, the AFR has dropped to 13 and I am getting EGO correction to try and bring it back to the target which would be somewhere between 13.5 and I think 14.5 (my RPM bins are at 900 and 1100 RPM and MS interpolates between bin values)



The maximum temperature skew corresponded to a Djet sensor reading of 33.5 C and manifold temperature of 46.4 C. The MAP during the test was around 68 kPa. I calculated the approximate fuel pulse width that Megasquirt would be calculating to deliver an AFR of 13.5 with the 68 kPa, 33.5 C air conditions. Using this approximate pulse fuel pulse width, I then back calculated the approximate AFR using an air temperature of 46.4 C instead of 33.5 C. This calculation suggested that the temperature skew between the Djet sensor and the actual manifold air temperature sensor was causing the AFR to drop to around 12.9. So, the difference in the temperature measurements could be altering my AFR on the idling engine by about 0.6 at idle.

I did a second calculation to look at the impact of the temperature skew on doing a restart on a moderately hot engine. I noted that about 5 minutes after shut down of the engine, the manifold temperature had climbed to 66.3 C. Unfortunately, I did not record the D jet sensor temperature since I had turned the engine off so I assumed it would be at 33.5 C which was the high point during the test. Using a MAP of 100 kPa (engine just on the verge of start up), I estimated the Megasquirt fuel requirement calculation to deliver an AFR of 13.5 based upon the 33.5 C Djet sensor temperature. Using this required fuel value I then back calculated the AFR with a manifold air temperature of 66.3 C. The AFR ended up at 12.4, so the temperature skew on a hot restart could potentially be causing the AFR to run rich by 1.1 points. This effect should diminish after the engine starts running and bringing in cool ambient air causing the manifold temperature to drop which should cause the AFR to increase. This is an effect that I have observed watching Tuner Studio during hot restarts. If I had planned out my test better, I would have executed a restart on the engine to see how quickly the manifold air temperature dropped. Unfortunately, I did not do this.

It would appear that the sensor location could be contributing to my mixture changing between hot and cold idle conditions. I don’t know that it is the only factor or just a contributing factor. However, I have ordered a GM open element air temperature sensor which I am going to install in the location of the unused cold start injector. Unfortunately, this is going to require that I remove the manifold to drill and tap it for the 3/8” NPT thread on the sensor. Having both sensors will allow me to do some A:B testing of the effect of sensor location and see whether it resolves of improves my mixture issue.

I should note that this issue of the impact of the air temperature sensor location is primarily an issue for idle performance and starting (right now I can tune the Ve table for hot starting or cold starting, getting both perfect is eluding me). I should also note that I may be a little picky since after working through my initial glitches, I have never had an issue of failure to start or really difficult starting (yet). Once the car is moving, I expect that the temperature skew between the D jet sensor location and the actual intake manifold temperature may be a bit of a non issue. At higher engine loads there is probably enough airflow through the intake system to minimize the temperature difference between the inlet and the manifold. Of course, I say that without benefit of actually confirming it by test (I couldn’t do a moving test of intake manifold temperature if I wanted to have brakes!).

I will update after I get my manifold air temperature sensor installed and do some testing.

[cwdodson88]

Have your turned your After Start Enrichments off to see if that fixes it?

[142 Guy]

Both the ASE and warm up enrichment had shut off by the time the intake manifold air temperature reached 28.5 C and I was starting to get more and more EGO correction to bring the AFR back to its target value. This problem with the fuel mix going rich only shows up after the engine is hot enough to cause a rise in air temperature between the stock D jet sensor location and the air in the intake manifold.

The GM air temp sensor should be here next week so I should be able to R&R the intake manifold, install the sensor and do a test to see if things improve with the air temperature sensor mounted in the intake manifold.

[142 Guy]

I had decided that I was going to install the manifold air temperature sensor in the hole where the cold start injector fits. The cold start injector is not used by Megasquirt so I had left it in the hole because it provided a convenient plug. The intake manifold wall is about 6 mm thick there and provides a reasonable thickness for tapping to receive the 3/8 npt thread on the GM air temperature sensor that I had ordered. I removed the manifold and drilled the hole out with a 9/16 drill bit and then tapped it. The one thing that I did not anticipate was that a 3/8 npt tap is not the sort of item that is available at the large chain hardware suppliers. I ended up having to go to an industrial tool supplier – with an attendant industrial sized price!

I had thought about trying to drill and tap the hole with the manifold on the car, perhaps attaching a vacuum to the intake to pull out the aluminum bits as they fell into the hole. That would have been a disaster. There is enough oily residue in the manifold from the crankcase ventilation system that the aluminum shavings stuck to the manifold wall. It took me around 15 wash and rinses with solvent to get to the point where the solvent was washing out of the manifold without any filings.



With the cold start injector removed, I needed to block off the T in the fuel rail that supplied the cold start injector. I used a short section of 5/16” fuel line to connect a barbed to female pipe thread fitting and plugged off the pipe fitting with a recessed pipe plug. This gives me a convenient place to attach a fuel pressure gauge should that be necessary.


I recalibrated the Megasquirt controller for the resistance versus temperature curve for the GM sensor and started the engine up. I had checked the resistance of the GM sensor at an ambient temperature of 19.7 C which gave a resistance of 3450 ohms. The calibration table that I have specifies 3457 ohms at 20 C, so I am reasonably confident that the values I entered into Megasquirt from the calibration table match up with my sensor. After letting it warm up, I had to adjust some of the Ve table entries to achieve my target AFRs. My target idle AFRs at 900 RPM are 13.9-14. These rise to 13.5 in the adjacent 700 RPM bin so my strategy is to try and idle with an AFR of around 14 and if the RPM drops I allow the AFR to richen to help the engine recover speed. The real test as to whether the change in the IAT sensor location has improved things will come after I do a cold start and see if my AFR values are still on target with a cold engine. That will have to wait until tomorrow. The overnight temperatures are supposed to drop to -2 C so I should be able to get a reasonable cold start test tomorrow morning.

One thing I have observed is that with the temperatures dropping, the performance of the starter motor is somewhat marginal, as in slow. The voltage is good (a little less than 10 volts at the starter) and I am running a 5-30 synthetic oil, so battery condition and oil viscosity are about as good as it gets for cold weather conditions. It wasn’t so noticeable when the ambient temperatures were above 20 C; but, it is really quite noticeable now. I may have to investigate a gear drive starter installation.

[142 Guy]

The rather dirty garage queens out catching some late afternoon sunshine.

[142 Guy]

I have had a bit of a hiatus working on the car while waiting for a replacement for my leaking fuel pump and then some emergent house related items that needed to be taken care of quickly before really cold weather set in.

I still had my original 3 port pump and it appears that it developed a leak somewhere around the electrical connector. Rather than fool around with trying to fix it, I ordered a new one from VP auto. The pump that VP supplied is different from what is shown on their web site. It is an Airtex e2315. The pump works, the biggest fitment problem related to the length and diameter of the pump. The pump is longer by about 50 mm and smaller in diameter when compared to the original Bosch pump. Airtex includes a couple of dense rubber straps which you can use to wrap the pump and are supposed to take up the space between the original clamp and the pump body. The problem is that one rubber strap leaves the pump loose and two straps won’t fit under the clamp. I had to use one strap and some compressible closed cell foam to get a good fit of the pump in the clamp. Because of the extra length of the pump, if you mount the clamp in the middle of the pump, the clamp will no longer line up with the stock mounting holes in the 140’s pump holder. I had to drill a couple of new holes about 40 mm over from the existing holes so that the pump head would not bang into the end of the holder. The fittings that come with the pump are 5/16” and ½ “ barbed which works with the stock hose sizes, although the ½” was an incredibly tight fit.

The electrical connections to the pump are by eyed crimps which fit over a couple of lugs on the head end of the pump. Rather than do a purely bolt on connection, I fabricated about a 150 mm long pigtail with a Deutsche connector on one end and the eyed crimps on the other end connected to the pump. I cut the stock Bosch pump connector off and replaced it with a matching Deutsche connector. The Deutsche connectors are weather tight and will make it easier if I need to do maintenance in future. I covered the exposed electrical terminal posts on the pump with some short sections of heat shrink with the internal glue.

I temporarily plugged up the pump overflow line to the tank using the same type of bung as I used to plug off the cold start valve connection on my fuel rail. My plan is to completely pull off the overflow line to the tank and cap the T fitting on the tank with an appropriate npt cap; however, turns out that with a full tank of gas the return line fitting is below the fuel level in the tank and I can't pull the T fitting to measure the thread without having gas flow all over the place. Rather than drain the tank, I will just wait until I am down to about a half tank which should put the fuel level below the fitting.





The pump seems to work just fine and it has about the same level of noise as the original Bosch pump. Airtex says that it is a rolling element pump rather than a turbine pump so the similar noise should be no surprise. One up-side to the new pump is that restarts are faster since the fuel rail pressure does not drop off quickly like it did with the old pump after a shut down. Time will only tell on the long term reliability.

My reverse lights quit working again and investigation confirmed that the reverse light contact (I hesitate to call it a switch) on the transmission was no longer operating. I had trying doing a fix once before by straitening up the bent contact/spring. That clearly didn’t last so I ordered a new contact from High Performance Auto. The photo below shows the clearly mangled contact.



While groveling around under the car getting access to the reverse light contact, I discovered that my transmission mount has fractured. This is a bit irritating as I am sure it was a new mount. That is something that is going to have to wait until I need something else as the postal / courier fees on a single small item are too painful. Also, I don’t feel like groveling around under the car again as the temperatures are starting to drop here.

My brake warning light came on while I was driving around. My initial reaction was that it was the parking brake switch; however, investigation showed that it was the switch on the brake distribution block indicating loss of pressure on one circuit. My heart sank because I thought I had finally put all my brake system agonies behind me when I replaced my brake booster. Turns out that it was just the switch that had failed. I ordered a new switch from High Performance auto at the same time as I got the reverse light contact, installed it and all is well!

The car had been rolling around on tires that had a 1979 date code. The thought of doing any high speed runs on those tires to set up my Ve tables for the fuel injection left me cold. I ended up purchasing some H rated Michelin 185/65 15 all-season tires from Costco. Normally not my first choice for tire vendors; however, their price for the tires was, with the Cdn – US $ exchange rate, less than the price for the same tire from Tire Rack, and that was without adding in the shipping and brokerage costs. I also needed a new spare tire. The 185s will not fit in the spare tire well and the only 165s available in North America are from some no-name source. However, I did find some BF Goodrich radial TAs in a 155 size which has a revolutions per mile that is very close to the 185/65 Michelins. The spare I did source from Tire Rack as nobody in Canada had this particular tire.

With the recent cool weather, I have had a chance to do some tuning on cold start. I started out with cold cranking PW of around 7.5 mSec. I was tweeking it up gradually with hit and miss, but, mainly hit improvements. I finally got impatient and increased it to 16 mSec which has made a significant improvement. At this point the engine would start up pretty quickly and then immediately die so I started cranking up my cold after start enrichment. My cold ASE was originally around 66% and I am now at about 125% which has improved things significantly. I have also increased the cold count up to around 500 cycles to smooth the transition into the regular warm-up enrichment.

When I increased my cold cranking PW I also increased my hot cranking PW up to 4.4 mSec working up to around 4.8 mSec; however, I think I have gone too far and will have to drop it back as I have made my hot restarts more problematic.

While driving around in the evening, I discovered that I did not have any lighting on my heater controls. The heater control lights are now separate from my instrument lighting because the instruments are operated off of an inverter; however, I was sure that I had hooked the heater control lights up to the same supply as for the radio and AFR gauge lighting, which both work. Something more to add to the to-do list!

[142 Guy]

I ordered some front floor mats from Cocomats.com which arrived a couple of weeks ago. After I placed the order, they sent me a note and some templates to check that they were correct for the 142. Placing the templates in the car showed that they were about 4 inches too short and that the cut away for the gas pedal was incorrect. I marked the templates up for the throttle cut away, added about 4 “ into the length, marked the appropriate location for the heel pad and sent them back to Cocomats. The end product they sent back is really nice. They matched the cut up template that I sent them perfectly so they are an excellent fit. The mats have a very heavy rubber backing material with nibs so they don’t move around when you get in and out of the car. In my opinion the black / natural color mix in the mats goes well with the stock brown carpet and black leather upholstery. If there is a down side it is that they are not inexpensive.





I noted in my last post that I had been having problems with my starter motor failing to engage which required me carrying around a hammer to give the starter a tap on occasion. I decided to take a fling with one of the replacement Denso based gear drive starters. Suffice to say it was a bit of a fiasco, did not work out and I ended up putting the SR37X starter back in. I ended up ordering a SR437X starter from RockAuto. RockAuto sells rebuilt SR437X starters from a number of different vendors. I went for the Bosch rebuild which cost somewhere between $150 – 160 Cdn $ delivered to my doorstep.

The installation of the SR437X is slightly different than the SR37X because the 437X has threaded ears. It is meant to be installed by having the bolts inserted from the back of the bell housing and threaded into the threaded ears on the starter, eliminating the need for nuts. The appropriate bolt would be 12 mm, coarse thread (1.75 mm pitch), 85 – 90 mm long. On my 142 two things conspired against using the 12 mm bolts. The first is that the holes in the bell housing are a little too small for 12 mm bolts ( the holes in the block that match up with the bell housing are just fine). This would require drilling the bell housing holes out slightly, which would be an easy thing to do with the engine out of the car. Not so easy with the engine in the car. The second item was that because of the limited clearance between the back of the bell housing and the clutch / transmission tunnel, I don’t think it would be physically possible to insert a 90 mm long bolt from the back of the bell housing forward to thread into the starter.

I decided to improvise. A 10 mm bolt fits through the threaded 12mm ears on the 437X with a snug fit. I purchased some 100 mm long 10 mm bolts and inserted them through the starter mounting ears so that the retaining bolts are on the back side of the bell housing. The 100 mm bolt length is marginal, necessitating the use of a low profile nut with a nyloc locking insert. The bolt is just long enough to engage the insert with a complete thread pitch extending beyond the end of the insert. A better bolt length would be 105 – 110 mm which would allow a conventional bolt with lock washer and flat washer. However, the bolt vendor’s next size up was 130 mm which was way too long and I wasn’t inclined to do any cutting.

The only other minor installation issue is that the SR437X solenoid has two male spade connectors on it instead of just one as per the SR37X. I suspect that this second connector is to provide a starter engaged signal to the fuel injections system or a cold start injector. You can determine the correct terminal for the wire from the ignition switch by using an ohmmeter to measure the resistance between the terminal and the frame of the starter. The correct terminal will have some resistance (the solenoid coil) and the incorrect terminal will have infinite resistance.

Other than the bolt issues and the terminal for the starter switch, the SR437X is a direct replacement for the SR37X. In fact, because it is so much smaller and lighter (it weighed in at 8 lbs on my uncertified bathroom scale!) than the SR37X, it is much easier to install than the 37X. The SR437X starter is a nice upgrade relative to the SR37X starter. It spins the motor faster than the SR37X does and based upon the fact that the voltage as measured by my dash voltmeter is not dropping as much as it did with the SR37X, I expect that it is drawing less current during cranking (which it should since it has permanent magnets as opposed to wound field windings).



With the new starter in place, I have been doing some more testing of my cold start with Megasquirt. The weather here has conspired to facilitate this! The engine generally fires quickly after about two crank rotations and then promptly dies. This suggests to me that the cold cranking pulses are OK and that I need to further increase the -40 C after start enrichment setting in Megasquirt. This is a bit of a protracted process as each time you do one of these failed starts it does warm the engine up slightly which then influences the after start enrichment setting so you have to let the engine cool before attempting your next start, even with an unsuccessful start. The hot restarts have been excellent.

I did have a bit of an unusual issue when I did my first start after I replaced the starter. The car hadn’t been run for about 3 weeks and when I got the engine going it idled at about 2700 RPM cold before dropping to about 1700 – 1800 RPM hot. Previously it had been idling at 900 RPM when hot. I checked to make sure that the throttle was closing on its stop and it was. I had to screw in the aux air adjustment screw to get the idle down. I am not sure what was going on, it almost seems like the Aux air regulator started opening more and admitting more air (or I have a new air leak in the manifold!). I have dropped the hot idle to 900 RPM and will see where the idle ends up when I attempt my next cold start.

[142 Guy]

I did a little more testing of the cold start today. With outside ambient air temperature of -7 C (garage air temp was around -4 C according to the IAT at start up), increasing the -40 C after start enrichment setting to 155% provided a quick start with no subsequent stumbling. I will have to wait for some colder temperatures to do some more testing.

I discovered the source of my mystery 2700 RPM cold idle. While installing the new SR437X starter, I must have accidently pulled the vacuum line off of the distributor resulting in an unplanned source of idle air. What was particularly satisfying was sticking the hose back on distributor (after the engine had warmed up) and having the idle drop from around 925 RPM down to around 700 - 750 RPM without stalling. It wasn't particularly smooth (perhaps because 700 RPM is at the edge of my fuel maps); but, I was impressed that it did not die.

[LloydDobler]

Awesome work, awesome car.

I'm sure once it's working perfect MS will be awesome but it seems like such a huge learning curve to figure out all the details, it's the one thing that really scares me off of it.

[142 Guy]

Awesome work, awesome car.

I'm sure once it's working perfect MS will be awesome but it seems like such a huge learning curve to figure out all the details, it's the one thing that really scares me off of it.

Thanks!

It has been interesting and this thing is a hobby and hobbies are for wasting time - right? Going through what is essentially a development process engenders a certain amount of respect for the automotive engineers who do this for every totally new engine design, and do it with the accelerated development cycles associated with new cars.

As an aside, once you do a little reading, I think tuning with MS is probably easier than tuning with SUs or Webers. Its really easy to change a few data entries, burn them, do a test run and then make a decision. I fiddled with Khein carbs on 4 cylinder Honda bikes. Changing main jets or adjusting needles was about as much fun as a root canal (I think the root canal was better because it took less time!). I think a lot of problems with MS installations result from hashed implementations. There is a lot of effort involved in planning out a good installation that will be reliable.

[cwdodson88]

I'm with you 142Guy, MS is pretty dang user friendly if proper steps are followed. TONS of reading, but in the end its nice to not have to open the hood to make changes.

[142 Guy]

This falls into the category of new is not always better or perhaps, know what you are doing when you mix your technologies!

In an earlier post, I noted that I had been having some problems with my voltage regulator. Every once in a while, I think it must have been sticking on the upper regulating contact on start up as the voltage would jump to between 16 and 17 volts and stay there. If I turned the car off and started it up again, it would always return to a normal operating range, so I was never able to actually test and confirm the problem.

I decided to try and address the issue by installing a new voltage regulator. I opted for one of the solid state adjustable regulators that Dave Barton sells. When I installed the new regulator and started the car up, the charge warning light came on and the dash voltmeter remained at the battery voltage, so the alternator was not producing any voltage. I checked for bad connections between the regulator and alternator and couldn’t find any problems. I switched the old regulator back in and things started working again. I went back and forth a couple of times between the new and old regulator to confirm that the problem seemed to be with the new regulator.

I emailed Dave Barton. After describing the problem and confirming that his regulator was a suitable replacement for my model # Bosch regulator, he mailed me a replacement regulator gratis and without any hassle. However, I decided to do one more test on the new regulator that I had. I hooked the regulator up with jumpers so that I could measure the voltage on the D+ and D field terminals and then started up the engine. I was measuring 1.5 volts on the D+ terminal and between 0 and 0.5 volts on the D field terminal depending on the setting of the regulator voltage adjustment. So, the regulator looked like it was working, sort of. I did a little investigation on the Bosch alternator. Apparently, it does not retain enough residual magnetism in the field to self-generate voltage and needs to be flashed to generate some initial voltage which it then uses to supply field current and ‘pick itself up by the bootstraps’ so to speak. Normally, it gets the flashing current through the charge indicator light on the dash which is connected between the battery and the D+ terminal. When I fabricated my new instrument cluster, I used LEDs for all of the warning lights. Unfortunately, the LED charge indicator light limits the current flow to the D+ terminal to about 0.02 amps. With the original electro mechanical regulator, which probably has a lower internal resistance than the electronic regulator, this was probably just enough to allow the field flashing; however, it might explain some of the initial issues I had with getting my rebuilt alternator to work. To confirm that the LED was the source of my field flashing problem, I connected a #37 dash indicator light to +12v and momentarily touched it to the D+ terminal on the regulator with the engine running. The voltage almost instantly jumped up to around 13.5 volts and I was able to adjust the idle voltage to 13.2 volts without any problem.

Clearly the LED charge indicator light does not provide reliable field flashing. To solve the problem, I will have to pull my instrument cluster out and install a #37 dash indicator light in parallel with the LED indicator light in the cluster. The mounting for the LED is semi-permanent so installing a parallel light bulb is easier than replacing the LED with an incandescent light bulb.

Mr. Barton will be getting his replacement regulator back with apologies!

[142 Guy]

The weather has turned decidedly warmer here in the last two weeks and just about all of the snow has disappeared, so I thought it was time to take the 142 out of hibernation. After removing the car storage bag and car cover, I had a look under the car and in the engine bay for any wet spots. Everything looked dry which was good. I confirmed the oil level was correct and the coolant in the overflow bottle was at half so that was good to go. I reconnected the ground on the battery. No sparks which was good and the headlights were nice and bright when switched on so the battery had retained its charge during storage. I pulled the primary fuse to the Megasquirt so that the fuel pump would be disabled and then engaged the starter for a few seconds until the oil pressure gauge was reading over 60 psi. I reinstalled the primary fuse and then engaged the starter for real. I turned the key to run, let the fuel system prime and cranked the engine for about 4 -5 seconds without any firing occurring. I tried a second time and after about 3 seconds of cranking, the engine fired and ran for about 10 seconds and quit. I tried a third time and the engine fired almost immediately and continued to run. I was feeling pretty smug about how quickly the successful start occurred after having been in storage for 5+ months. If I had the timer extended on the after start enrichment it might have stayed running after the second attempt.

Turns out the Norse God of Volvo doesn't like smug! After backing the car out of the garage so I could gather up the storage bag, I jumped back into the car to pull it forward and immediately noticed the red warning light on the temperature gauge with the gauge showing about 90C after running for only about 5 minutes. I turned on the interior heater; but, it was only blowing lukewarm air. I pulled the car into the garage, shut it off, popped the hood and had a look. Nothing was steaming or leaking, the overflow bottle level remained unchanged from the pre start check and the rad hoses were only slightly warm to the touch. I pulled off the rad cap and sure enough, the coolant was down about 30 mm from the neck. I wasn't liking where this was going. There was coolant missing. There was no leaked coolant outside of the car which meant that it had to be inside the car. Sure enough! Pulling the drivers floor mat out revealed soggy sticky carpet on the driver’s side. The passenger’s side was dry. My initial reaction was that the heater core had developed a leak. This was frustrating since I had the heater core out for cleaning and pressure testing while the car was being restored.

I pulled the carpet out of the car as I did not want to be lying on a soggy carpet while I investigated the problem. Also, the carpet was soaked through with coolant and removal would facilitate cleaning of the bottom and top side with one of those carpet shampooers. After wiping up the remaining coolant in the footwell, I reached up into the bottom of the heater to feel the core. All the areas that I could touch were dry and there was no sign of coolant draining out of the bottom of the heater. I reached around to the back of the heater and checked where the hoses fit over the barbed fittings on the back of the heater core. These were definitely wet indicating leakage at the hoses or a problem with the tubing on the heater. I grabbed my ¼” ratchet with an extension and checked the clamp tension on the heater hoses. They were not loose; but, not super tight either. I tightened the clamps as much as I dared.

I did not want to top up the coolant without first pressure testing the cooling system. I did not want to ante up the $ for a proper pressure tester so I rigged up the assembly in the photo below using my portable air compressor, fuel injection pressure tester and some brass fittings that I had.



I pressurized the system to about 15 psi and immediately heard hissing from my radiator cap. More frustration as the cap was on tight and this was a new cap. I grabbed my old cap from my junk box (this sort of thing is reenforcing my tendency to retain junk!) and installed it. On re pressurizing the system the old cap stopped the leaking at the cap; but, I now discovered that I was leaking coolant on the top and bottom radiator hoses and on one of the hoses on the heater valve. The up side was that there did not appear to be any leakage from the hose connections on the back of the heater. I tightened all the clamps on all the hoses and then pressurized the system to 15 psi with no visible leakage. I then increased the pressure to 20 psi and let it sit overnight with no wet spots showing up after 12 hours.

I know that I tightened all the clamps when I assembled the car. When I did the initial start of the engine last year, after a couple of hours of on and off operation, I had some leakage on the lower rad hose and one of the heater valve hoses. At the time I checked the back of the heater because I was paranoid about getting coolant in the interior and all was dry. I can only surmise that with the applied pressure of the hose clamps and some heat cycling, the rubber under the hose clamps is creeping and relaxing the pressure that the clamp applies on the hose allowing the subsequent leakage. The relaxation in the clamping pressure must have been significant as approximately 0.7 l of coolant leaked from the heater hose connections with no pressure on the system during the 5 months the car was in storage (the carpets were dry when I put the car into storage). Whatever the problem, I am now suitably paranoid and will be checking all the hoses for signs of leakage regularly, at least for a while.

The brand new leaking rad cap was a bit of a mystery. Comparing the new and old caps, the old cap required a fair amount more force to twist it into the locked position. This suggested that the dimension from the locking ears to the rubber liner in the cap may be too large to get a tight fit. While my original cap appeared to be sealing, its rubber liner is close to 45 years in age so I was reluctant to continue using it, plus the decal on the top had disappeared and it generally looked beaten up. I thought that perhaps I could put a shim under the rubber on the new cap to create a tighter fit so I pried out the rubber liner and discovered that there already was a brass shim under the liner. Unless the shim is there to allow the cap to rotate while the rubber liner stays in one place, I can’t think of any reason for the shim unless the manufacture knew that there was a spacing issue with the retaining ears. Anyway, I cut a couple of shims from some 0.005” brass sheet that I had and added them under the rubber liner with the existing shim. So far, that has solved the problem of the leakage from the new cap. Something to keep an eye on if you purchase a new cap for you radiator!

[Lesky]

I've experienced the exact same issue with radiators caps on my 164!

If you need specialty tool items in the future, I like MSC industrial supply. MSC, in my opinion, is usually pretty reasonable. Here is a link to a 3/8 npt hand tap: http://www.mscdirect.com/browse/tn/T...navid=12106056. I expect that MSC does business in Canada, but I don't know for sure. Also, Grainger is another good source for those things.

Your troubleshooting is very thorough. I like how you really get to the root cause. Keep up the great work!

[142 Guy]

I have been picking away at a few items on the car in the last couple of months. First off, to what may the most useful item for some owners, more driver leg room! I am just a hair under 6’ tall with 33- 34” inseam, pretty normal. I found that even with my small Moto Lita steering wheel, operation of the clutch and brake pedals required that I splay my legs out to the side to avoid them hitting the bottom of the steering wheel. I imagine it must be a real pain if you have the stock steering wheel. The owner’s manual describes the adjustments at the front and back of the seat which can be used to raise / lower and tilt the seat base. Fiddling with these did not yield much of an improvement. I decided to look at the seat base to determine if there was some way that I could drill some holes to allow me to mount the base further back on the adjustment mechanism. I popped the cushion off and discovered that the seat base already has an extra set of holes drilled in the mounts, both at the front and the back. The photo below shows the extra set of mounting holes.



The red arrow shows the mounting hole that the seat used from the factory. The yellow arrow shows the second mounting hole. Its an easy 15 minute job to remove the four mounting bolts, slide the seat base back and reinstall them. The second set of holes allow you to position the seat base back slightly more than 30 mm. This may not seem like much; but, it does make a remarkable difference in leg room. If you needed more leg room, by removing the seat you might be able to drill another hole in front of the hole marked by the yellow arrow. However, you are not going to gain a lot. The piece of steel that forms the mounting base starts to curve upward to the point where it is welded to the tube around the periphery of the seat base. You might be able to get an additional 10 mm or so before running into this curve. My only concern with doing this might be that the holes would be very close together which could weaken the mounting point.

If this adjustment is common knowledge, I apologize for making a big deal. It certainly wasn’t common knowledge for me otherwise I would have done it a long time ago!

[True142]

That's definitely good to know since I feel the same way sitting in my 140. Do you have an adjustable rod at the center/front of the seat or a hand lever?

[142 Guy]

Adjustable rod. All seat adjustments definitely require breaking out the tools!. Is there a lever adjustment mechanism on later cars?

[True142]

I think so. I started a new thread on it, because I didn't want to put pics into your thread.

Sent from my SGH-M919 using Tapatalk

[Lesky]

This is going back a ways, but what is Prussian Blue (used on your valve seats)? Is it the blue dye that is used to mark up sheet metal?

Also, did you or someone else paint your engine? Any recommendations on a good spray can product?

[142 Guy]

This is going back a ways, but what is Prussian Blue (used on your valve seats)? Is it the blue dye that is used to mark up sheet metal?

Also, did you or someone else paint your engine? Any recommendations on a good spray can product?

Yes, Prussian Blue is another name for that blue layout dye used be machinists.

I painted the engine.

The valve cover is definitely painted with VHT silver caliper paint. I believe the intake manifold and other cast alloy parts were also painted with VHT silver caliper paint. However, I might have used VHT aluminum high heat manifold paint on those parts. I am inclined to believe that I probably used the caliper paint on all the parts because the caliper paint has a slight gloss and the manifold paint has a flat finish. Its hard to tell on castings; however, they do look like they have a bit of a gloss. The VHT silver caliper paint has been durable so far.

The block is painted with either Dupli Color High Heat Ceramic in DH1608 red or Dupli Color Engine Paint in the Ford Red. I had a little bit of the DH1608 left and I went out to the car to compare the cap color with the block. It looks like I used the DH1608; but, cannot be absolutely sure. The bad news is that the DH1608 appears to be out of production. If you can find it, it is a durable paint and when cured is rated at 649 deg C.

Prep is key to using a spray bomb. After sandblasting the head and block, I degreased them with a 20% acetone in water solution and then after drying, sprayed them down with POR Metal Ready. The alloy parts were just degreased with the acetone / water mix. To get a good finish, I had to spray slow and steady. You want the spray to be heavy enough to wet the surface so that you get a reasonably glossy finish. If you move the spray bomb to fast you don't get enough paint on the surface and it does not flow out nicely leaving you with a slightly textured surface. Too slow and you end up with runs.

Sorry that I can't be more specific on the colors.

[142 Guy]

I think I noted in a response to some questions in the 1800 forum that I have been chasing some problems with my O2 sensor and the Megasquirt. This spring, I noticed that while driving around, the AFR meter on my dash would on occassion hang-up, sticking at random AFR values. What was interesting was that the meter always started operating again if I stopped the engine and then did a restart (the AFRs seemed reasonable ; but, I cannot be sure they were accurate). After this repeated a couple of times, I hooked my laptop up to the MS and confirmed that the AFRs as they were being input to Megasquirt were also hanging up so the problem wasn’t just a failing AFR meter. Both analog outputs from the LC1 O2 controller appeared to be going south. While the laptop was hooked up to MS, I also started to experience a lot of serial port communication failures to MS and noticed that I was getting a fair number of resets on the MS.

I decided to work on the LC1 controller issues first. The monitoring LED for the LC1 was not flashing any error codes when these lock-ups occurred so I connected the laptop up to the LC1 serial port to log the LC1’s output and see if the serial data was freezing up at the same time as the analog outputs. After a couple of events where the analog outputs froze up, the serial data also froze up. Finally, on one occasion the analog data froze up; but, the serial port remained active. The serial port stopped transmitting AFR values to the laptop; but, did generate an error message indicating error 2 – open heater circuit in the sensor. I fiddled with the sensor cable connector at the controller to see if it was just a bad connection; however, this did not resolve the problem. I ordered a new O2 sensor and installed it. The #2 error code did not re emerge; however, the controller continued to lock up. I put the original sensor back in and same thing, no error code and hit and miss operation so I think the error code was false.

The LC1 installation manual is a bit vague about the sensitivity of the controller to heat. It just says to mount it as far away from heat sources as the cable allows. The cable from the sensor to the controller is not very long so I ended up mounting the controller on the firewall just above the inside fender. The photo below shows the location where the controller use to be – approximately where that grey 6 pin Deutsche connector is located.



The location does get radiant heat from the header and I was starting to wonder whether the heating was causing the internal components in the LC1 to go out of tolerance leading to an operational failure of the controller. I decided to relocate the controller into the interior of the car where temperatures were a little more moderate and the controller would not be subject to the radiant heat from the header. I fabricated a clamp and mounted the controller on the glove box supporting bar that is located just behind the glovebox. This precipitated some rewiring and also required an extension cable to the O2 sensor. I got some nice 120 deg C rated wire from a local specialty shop and enclosed it in a woven high temperature jacket. I cut the original terminator off of the O2 sensor, soldered this on to the end of my extension cable and added a Deutsche 6 pin connector on to the end of the extension cable. I connected the matching Deutsche connector on to the end of the O2 sensor cable.



Relocation of the LC1 controller into a cooler environment seemed to resolve this operating problem.

While this was going on, I got into a discussion on the 122 forum about the impact of the Pertronix ignition module on ignition performance, particularly when the battery voltage was low. It was noted by another poster that the switched on-state voltage of the Pertronix was around 1 volt which could reduce the peak current to the coil during the dwell period. This rather high voltage intrigued me so I hooked my scope up to the coil negative terminal to verify this voltage. While standing by the car with the hood running with the scope connected up (confirming that the switched voltage was in fact right around 1 volt) I heard an occasional snapping sound corresponding to an engine misfire. These were irregular. The B20E is not exactly a quiet engine; but, as far as I could tell they were coming from the ignition coil tower. Unfortunately it was bright sunlight so I couldn’t see if there were any visible flashovers.

I shut the engine down and pulled the cable from the coil to the center of the distributor. I carefully examined the terminal and boot for signs of tracking and made sure that both metal terminals were secure. For good measure I took some brake cleaner and cleaned both cable terminals and the coil tower insulator, reapplied some dielectric grease to the cable ends and then reinstalled the cable. I restarted the car and the snapping noise did not reappear. Since the cable ends appeared to be OK and there did not appear to be any tracking on the cable or the coil tower, I am wondering if the cable was not pushed into the coil tower completely; however, if that was the case, I would have expected the snapping and the misfires to be more regular. Anyway, the random flashover / misfire problem has not reappeared. What is also interesting is that coincident with this little fix, the resets on the MS and problems with the MS serial line communication failures to the laptop have completely disappeared (at least for the last 3+ weeks).

Voltage transients on the +12 v DC supply to Megasquirt can initiate resets and screw up the serial data line. When I had the apparent coil flashovers events, these events were not showing up on the 12v supply to the MS and the LC1 when I checked with my scope. The 12v supply to the MS and LC1 come directly off of the 12v distribution block so there is not a lot of common coupling to other stuff on the car (I was checking to see whether things like radiator fan switching or other electrical items switching were causing transients). Both the MS and LC1 have all their ground points brought out to a common connection point on the intake manifold, so I don’t think anything was getting coupled back through the grounds. If the coil was flashing over to the negative terminal of the coil, then these voltage transients could have been coupled back into the MS on the line that provides the tach signal to the MS (the MS currently gets its tach signal off of the negative coil terminal). However, I am still at a bit of a loss as to exactly what the problem was.

Following the coil flashover event, I am also left wondering whether my LC1 issues were temperature related or whether they were also caused by the voltage transients. This might explain why the LC1 would start working immediately after an engine restart even though it was still hot. If the problem was heat related I would not expect it to become operational until it had cooled off. If the transients were being coupled into the common +12v supply to both the MS and LC1, I could see this as a possibility. However, I didn’t see any evidence of that and my current best guess is that the transients were getting into the MS via its tach signal. How this would screw up the LC1 is a bit of a mystery. That said, things have been stable for the last three weeks or so MS and LC1 wise. The relocation of the LC1 from the engine compartment to the car interior was probably not a bad thing. Heat is not a friend of electronic devices.

[142 Guy]

I was driving around in the 142 on the weekend and noticed that when I came to a stop at any reasonably long traffic light, the engine temperature would start to rise fairly quickly and on one occasion it caused the warning light to come on which is set at 100 C. The temperature would immediately start to drop as soon as the car started moving. At a convenient stop I opened up the driver’s window and could not hear the electric rad fan running, so I switched on the interior fan, opened the vents and set the heater control to hot. This eliminated the warning light coming on when the car was stopped and I was able to get home without incident and importantly, no boil-over. It wasn’t pleasant as the ambient air temperatures were in the low 30s and it was a cloudless day with a very bright sun. Not a good mix with a black leather interior at the best of times. Turn on the heater and I think I had the interior temperature up into the low 40s even with the windows open.

The first thing I checked was the fan fuse which turned out to be open. I put a replacement in and turned the ignition to run; however, the fan did not switch on. Since the fuse had blown, I was suspicious about the fan motor so I used a multimeter to check for an internal short. The motor resistance tested out to a reasonable value so I connected it directly to the 12v supply and it appeared to run fine. Since the fan relay is switched by Megasquirt applying a ground to the relay coil 86 terminal, I thought perhaps there might be something amiss with the switching circuit from the Megasquirt. I grounded out the 86 terminal of the relay coil with a jumper and could hear the relay switching. I connected the fan back up to the relay and then switched the relay again using the jumper. I could hear the relay clicking; but, the fan did not operate. This was a mystery! I connected the multimeter to the relay 87 terminal that supplied the fan and used the jumper to switch the relay. No voltage on the 87 terminal even though there was 12v on the relay 30 terminal and the relay was clicking. The relay appeared to have failed, something I have never experienced unless the relay was undersized for the application (it was a 30 amp relay switching a DC motor load of slightly less than 10 amps). I replaced the relay and everything is now working fine.

Curious about the relay failure, I pried the cover off the failed relay expecting to see a damaged moving contact or something similar. However, the relay internals appeared to be as new. I did notice that on the base of the relay around the 87 terminal, it appears as if the plastic has melted slightly. You can see that in the photo below. There is also evidence of slight melting on the side of the relay base suggesting that the terminal got hot. I though perhaps the push on crimp connector to the fan was loose which had resulted in a high resistance connection on the terminal causing the heat. However testing the connector showed that it was a good tight fit and there was no evidence of overheating on the connector itself. Although it’s hard to tell from the photograph, the exposed portion of the relay 87 terminal that the connector pushes on to shows no sign of heating or damage so I think the problem is internal to the relay. I may have to saw open the plastic base of the relay if I want to figure out what happened.



As I noted, it has been quite hot here lately. With the + 30C temperatures, I have noticed that when I come to a traffic stop, the engine temperature gauge will start climbing from its normal operating point of around the high eighties into the low nineties fairly quickly even with the rad fan operating. Once the car starts moving, the temperature drops right back to the high eighties. This temperature behaviour is probably precipitated by a couple of things. First I am using a digitally controlled gauge which has an analogue movement driven by a stepper motor. As a result, the gauge probably has a very fast response to temperature changes, certainly compared to the bimetallic gauge mechanism that Volvo uses which probably has a time response in the seconds to tens of seconds. The second is that I am using a 12 in pusher fan arrangement. The heat transfer performance of the pusher arrangement is suboptimal compared to the pull arrangement even without consideration of the fact that the pusher precludes the use of a fan shroud. This subpar performance is exacerbated by the fact that because of the mounting method I used, the surface of the fan is probably 2 cm back from the front surface of the rad reducing the effectiveness of the shroud on the blade tips. I do get a fair amount of backwash from the fan when the car is just sitting idling.

The temperature swings when the car comes to a traffic stop may or may not be an issue. They may not be noticeable with the OEM temperature gauge and I am wondering if anybody that is using a digital gauge or non digital gauge with a faster galvanometric movement has noticed similar temperature swings when coming to a stop. My second question is that assuming I do have marginal cooling, it looks like the largest fan that I could install in the pusher configuration would be a 15” diameter unit. Does anybody have experience with mounting a 15 “ fan in the pusher configuration on the later cross flow radiator? If so, what was the make of the fan?

Just to address the obvious questions, the rad was acid cleaned and pressure tested prior to the car being put back into service and the thermostat is new. When the car is moving the engine temp is a non-issue so I expect that any idle temperature issues that I have are due to a lack of air movement rather than a radiator or thermostat problem.

[142 Guy]

Fuel pump agony!

The 142 took some damage from a hail storm back in June which required that I take it to the adjuster. It was a large crowd. They had set up the adjusters in a very large building and were processing what looked like 40 to 50 vehicles every 30 minutes running from 08:00 to 20:00 for several days. I came out relatively OK, a few dents, perhaps 30 that paintless dent repair will fix no problem. The nasty part is the dents to the trim around the front and rear windows and the polished part around the front grill and headlights. Getting those fixed up and repolished is going to be a little more hassle.

The reason why any of the above is relevant is that it was a fairly hot day when I made the visit to the adjuster. After the inspection, I went to start the car and I noticed that the fuel pump seemed rather noisy. It then turned out to be quite difficult to get the car started and running. It took three tries before it would sustain operation and it initially ran quite rough. However, I was able to get it home without incident. I did notice that immediately following the third, successful try, the AFRs seemed to be jumping quite high. This persisted for a minute or two and then they seemed to return to their normal operating range.

The next day, I went out to do a little investigation as to what was going on with the car. I did a cold start and let the engine run through the after start and warm up enrichment. I again noticed that the pump seemed really noisey. Once the FI was off of the enrichments, I noticed that the AFRs again seemed abnormally high and then returned to more normal values. I connected up my laptop and found that immediately after start up, I was running very high AFRs and that as soon as the conditions were right to go into closed loop operation, I would get large amounts of EGO correction and the AFRs would come close to their target values. I hooked up my fuel pressure gauge and found that my static pressure was only about 24 psi (I have it set up for 28 psi) and when I started the car up I could see the fuel pressure fluctuating +/– 4 psi as the injectors were opening and closing. Since I had installed a new Airtex pump from VP Auto last fall, my initial reaction was that my fuel filter or the suction filter must be plugged up. I was quite concerned as I has coated my tank as part of the restoration process and was concerned that the coating had failed and was clogging the filters. However, skipping through the details, both of the filters were just fine and all my fuel lines were clear. The problem appeared to be the Airtex pump.

I replaced my original Bosch pump last fall because it had developed a leak around the electrical connector. However, as luck would have it, it was still sitting on a shelf in the garage. I got some epoxy sealant and filled the area the connector. After the epoxy set up, I did a temporary hook-up of the pump and started the car up. No problem, much less noise and the fuel pressure measured at the rail was rock solid (no fluctuations due to the operation of the injectors). Clearly, my Airtex pump had bought the farm. I don’t know whether my Airtex was faulty from the get go or they are not a correct application for the D Jet. Anyway, I decided that I did not want to try again with a second Airtex pump.

I looked around for alternatives. The Walbro pumps seem to be fairly popular, however, they have straight through end fittings with m10 threads. You can get an m10 to 5/16 barbed straight adapter for the outlet; but, I needed a 90 deg bend at the outlet so I was going to have to do a m10 to NPT adapter followed by a NPT to 5/16” barbed fitting. Same thing on the inlet. I could not find a m10 to 12 mm barbed fitting (or ½” - close enough!) for the inlet. I was going to have to do another m10 to NPT and NPT to ½” barb which was going to result in a really long pump. The Aeromotive and similar pumps had the same problem. The common in-line designs don’t work very well if you want to retain the stock mounting arrangement on the 142.

I did a search on the Bosch application guide for replacements for the original 3 and 2 port pumps. Bosch lists a superseded part number for these pumps, which has a subsequent superseded number ..... I could not find anybody offering any of these subsequent Bosch part numbers for sale. However, a search on one of the part numbers led me to a classic Mercedes owners forum where there was a thread discussing problems getting replacement pumps (some of the early 70s MBs used the D jet. By luck, one of the posts mentioned that the fuel pump used on the late seventies early eighties 280 ZX was a direct fit for the pump used on the early MBs. I did a search on Rock Auto for a 1979 280 ZX fuel pump and up pops a Beck Arnley fuel pump which looks to be a dead ringer for the 2 port Bosch pump used on the later D jet systems. I check the application guide listed for the pump and it shows that it indeed fits the early Mercedes cars with D jet. Close examination of the fuel pump photo showed that it sure looked like it had a 5/16” barbed outlet and a ½” barbed inlet. The only obvious difference was that the electrical terminations are by bolt on connections (the more common current connection method) rather than the push on plug used by Bosch. Also, the electrical connector and the outlet port are on opposite sides of the pump body whereas on the Bosch pump, they are on the same side. The down side is that the Beck Arnley pump was a little pricey, in the $400 range with shipping as I recall. I view the Beck Arnley stuff as being pretty good quality; but, wanted to see if I could do better on the price. I did a little web search on 1980 Datsun 280 ZX fuel pumps and found a bunch of listings on Ebay. By luck, I found a vendor who appeared to be clearing out their stock of OEM pumps for the 280 ZX for $240 US so I grabbed it. If it is OEM Nissan, I figured it would not be junk.

The pump arrived today. The photo below shows the part number. From the date code on the box, it is either 9 or 10 years old (is it mo/yr or yr/mo?) which was a bit of a concern initially. However, the pump was tripled bagged and the ports were well sealed and when I pried the seals off, oil drained out so deterioration probably is not an issue. Based on the production date, I am guessing that the vendor was probably clearing out inventory that wasn’t moving.



Opening up the box to look at it, I almost expected to see a Bosch stamp on the back of the pump. Other than the terminal arrangement and 180 deg orientation of the discharge ports, it is a dead ringer for the early Bosch pump. The pump body diameter is identical, the little locator pins on the sides of the body are identical, the bolt centers for the pump head are identical, even the webbing on the end casting looks identical. It is, however, about 5 mm shorter in total length. It almost looks like Datsun / Nissan licensed (or borrowed) the design from Bosch.





Since the pump is virtually identical to the original Bosch pump, installation is a relative breeze (after undoing the modifications required to fit the Airtex pump). Most of the effort went into modifying the electrical hook-up. One thing to note, since this is an OEM replacement as opposed to a universal fit pump, it does not come with any electrical connectors. The studs for mounting the electrical connectors are metric and the + and – stud sizes are different diameters requiring different lug sizes. I guess that is how Datsun made sure that pumps were not installed with the polarities reversed.

Following installation, I proceeded to prime the fuel system by manually operating the fuel pump relay. I was initially concerned because I could hear the relay click; but, I didn’t hear any pump operation; however, after actuating the relay a couple of times, the gauge connected to the fuel rail started to move. The gauge indicated that the regulator was set slightly high so I shut the pump off and adjusted the pressure down to 28 psi. I then clamped the pressure reference line to the regulator and started the engine. With the reference line clamped and the engine running the fuel pressure held steady at 28 psi so I removed the clamp on the reference line and the fuel pressure dropped to about 22 psi which is about correct for the manifold vacuum at the time. The pressure gauge did not exhibit any of the significant pressure fluctuations that the Airtex pump was showing. This is a symptom that the Airtex pump had demonstrated from day 1; but, had started out as very small fluctuations before evolving to the large pressure swings I had witnessed. Because I was curious, I walked to the back of the car and bent over to see if I could hear the pump running. With the sound from the exhaust, it was not possible to hear any noise from the pump.

Only time will tell if the Nissan pump turns out to be as or more reliable than the original Bosch pump. I don’t think meeting the bar of being more reliable than the Airtex pump will be too hard to achieve. That said, if you are looking for an almost exact fit replacement for the original 2 or 3 port Bosch pump, the Datsun / Nissan pump looks to be an excellent candidate. I will update with any reliability issues.

One of the consequences of this pump problem is that I will likely have to redo some of my fuel map. After finally getting my fuel maps in sort of reasonable shape, I had recently purchased a copy of Tuner Studio with the auto tuning feature to do the fine tuning of the Ve tables. I had been driving around for a couple of weeks with the auto tune feature enabled allowing it to update the Ve table; however, it was likely updating the tables based on the AFR values it was getting from the O2 sensor with fuel pressures that may have been all over the place. I get to start that process all over again!

[LloydDobler]

Excellent detail in your posts, and that sucks about the hail! Those aluminum grilles are so delicate and once bent it's hard to get them to look right ever again. I hope you have a good metal guy (or are one).

[142 Guy]

I will characterize my latest update as 80% activity and maybe 20% progress.

Prior to my last round of fiddling with the fuel pump, I noticed that the discharge line coming out of the bottom of the fuel pressure regulator was kinking a bit. Thinking that this kink might be restricting the discharge flow and affecting pressure regulation, I acquired a 90 ° barbed fitting which allowed me to run an almost straight section of rubber gas line over to the start of the hard line back to the tank.



After I replaced the fuel pump, I noticed that even though my fuel pressure was pretty consistent, I was getting a lot of howling noise from the FPR. Being solidly mounted to the firewall it has a pretty good sounding board. The howling is not continuous; but, particularly noticeable during throttle transitions when you are lifting off or pressing down on the throttle. I did some searching on the web and about the only relevant discussion I could find was some opinions that FPRs do not ‘like’ sharp transitions on the attached lines, particularly on the discharge line. Since I was not having any other success in explaining the noisy regulator, I removed the 90 ° barbed fitting and replaced it with a straight barbed fitting. In order to get a larger radius bend on the discharge hose, I relocated the FPR mount in the other OEM mounting hole which placed the regulator about 30 mm to the right side of the car. This plus adding a P clamp on the throttle cable mount to support and keep the discharge hose in one location allowed me to execute the larger radius bend.



The larger radius bend on the discharge line has greatly reduced; but, not totally eliminated the noise during throttle transitions. Aeromotive recommends a 3/8” discharge line and the OEM Volvo uses a 5/16” discharge. Both the Volvo B20E and the Datsun 280 ZX whose pump I am now using seemed to work fine with a 5/16” discharge line; however, it may be that the Aeromotive regulator is acutely sensitive to back pressure on the discharge line. It is worth noting that both the OEM FPR and the Datsun 280 ZX FPR (which I briefly experimented with but ditched because of its higher regulating pressure) had large radius bends in the section of steel line connected to their discharge ports, so the sharp 90 ° barbed fitting that I was using was probably a bad idea. I might at some point reconsider the 280 ZX FPR which would require slight reprogramming to deal with the higher flow rates associated its 36 psi regulating pressure. I had rejected the higher operating pressure because of the higher flow rates it gave to the already generously sized OEM injectors.

If you have been following my posts, you will be aware that I have been chasing a marginal hot running problem with the car which has emerged with the quite warm weather that we have been experiencing this summer (day time highs in the 30 – 35° C range with lots of sun. The solar gain in a Volvo 142 green house / suana with black leather interior and no AC is pretty much unbearable! I now pretty much have to do my test driving in the morning or evening.

I think I had noted that my 12” pusher fan arrangement was probably marginal, so I ended up ordering a Speedway Motors 15” house brand electric fan. With the plastic mounting shroud around the fan, 15” is the largest fan that you can fit in a pusher configuration. Installed, I only have about 1/8” clearance from the front edge of the shroud to the sheetmetal in front of the radiator. You could fit a larger diameter fan in the pull configuration; however, I was not able to find any electric fan shallow enough to fit between the radiator and the snout of the water pump.



The 15 “ fan did seem to reduce the running hot problem. However, while running my hand along the back of the radiator to check the airflow, I determined that the temperature of the air exiting the lower right side of the rad below the radiator discharge connection was barely above ambient. Touching my hands to the fins showed that they were cool. I ran my hand over to the inlet side tank which was pretty uniformly hot. I then ran my fingers along the fins on the bottom part of the rad from the inlet side to the discharge side and there was an abrupt transition in temperature about midway across the rad. Clearly there was a blockage in the lower part of the rad. Based upon the finger temperature measurement, this blockage only existed in the tubes located below the radiator outlet. The approximate location of the blockage is marked by tape in the following photo:



While getting things ready for restoring the car, I had the rad cleaned and pressure tested by a radiator shop about 5 years ago. Clearly their cleaning was a little faulty. I pulled the radiator and took it to a different shop for repair. After getting it back from the shop, I stuck a garden hose in the radiator outlet, turned on the water and looked down the filler opening to confirm that I was getting water flow through the lower tubes. Seemed to be OK.

I reassembled everything and started up the engine and let the cooling system go through the purging process. After cool down and a top up, I restarted and let the car just sit and idle. With an ambient temperature of around 31 ° C, the dash temperature gauge which uses the sensor location at the back of the head climbed up and parked perhaps just below 95 ° C. I had the laptop connected up to the Megasquirt and could see the temperature measurement on the old Djet temperature sensor located at the front of the block. It was hovering right around 82 – 83 ° C. I took the car for a spin and after about 3 minutes driving I noticed that the dash temp gauge had dropped to about 85 ° C with the front mounted sensor still giving 82° C. Relatively steady driving at 50 kph caused the dash gauge to pretty much flatten out at around 84 – 85° C. I brought the car home, parked it; but, let it idle so that the dash gauge rose up to somewhere close to 95° C with the Megasquirt temperature measurement holding steady at 82° C. I then pressed the gas pedal down to increase the engine speed to a little over 2000 RPM and the dash temperature gauge immediately started to drop; however, I didn’t continue this to see how far I could get it to drop. Since the temperatures as measured by the Megasquirt are rock steady around 82 ° C, my conclusion is that any ‘running hot’ issue I may or may not have is now no longer a radiator or cooling fan issue. The thermostat is able to regulate the cooling loop temperature without any problem.

There could be a number of answers to the hotter running dash gauge. It may be possible that the B20 block has a natural temperature skew from the front to the back with the back running hotter; however, this skew pretty much disappears at higher engine speeds. It is possible that the internal water distribution pipe in my head is out of position which is compromising the cooling of the back part of the head. If so, it is only a problem after extended idling. The aftermarket water pump I have may have a flow rate at idle which isn’t quite what the OEM water pump has. Again this problem only manifests itself at idle engine speeds. Finally, my dash gauge uses a non OEM sensor which required an adapter to fit in the hole at the back of the block. As a result, the sensor sits high and may be out of the path of the coolant flow. At low engine speeds the coolant flow may not be providing good circulation around the sensor causing it to read a locally hotter temperature. Whatever the reason for my temperature bias, it only manifests itself after protracted idling and with the larger rad fan and radiator cleaning job, my back of block temperature is not approaching boil over and my front of block temperature is pretty much right at the thermostats set point.

I will continue to monitor the dash gauge; but, stop obsessing when it climbs a little bit when I am stopped.

[142 Guy]

A little more activity and I think some progress.

I had been having a slight misfire issue which was noticeable at idle as the odd shake in the engine. At idle I am running around a 13.5 – 13.7 AFR so I was pretty sure it was not lean misfire. I hooked up my scope to one of the analog outputs of the LC1 wideband controller and sure enough you could see the output voltage doing the occasional transient drop. I would have used the logworks data logging and included a copy of the log here to show the dips; but, the LC1 seemed to be having one of its serial port incommunicado episodes and I didn’t have the patience to play with it. I got my inductive timing light out and connected it to the four plug leads successively to see if I could isolate the misfire to one cylinder based on erratic flashing of the timing light; however, erratic operation showed up on all 4 leads. I then proceeded to clip the pick-up to the coil tower lead and received a taser jolt when my finger touched the coil wire insulation. I had just discovered the source of the misfire! In a way this did not surprise me as a couple of posts ago, while trying to track done the cause of repeated Megasquirt resets, I mentioned that I had heard what sounded like spark snaps around the coil terminal; however, investigation at that time showed no insulation failure and the problem seemed to go away.

I pulled the coil wire out and looked at it. It still did not show any external signs of tracking. However, after pulling the boot back, it was possible to see a very slight track in the insulation jacket leading to the edge of the boot. In the following photo, you can see that they have crimped a section of the plug wire core (black stuff) under the terminal and that this core extends from under the end of the terminal by about 2 – 3 mm. From the end of the plug core you can just see the faint track on the surface of the insulation.



The spark plug wire set was a new custom set from IPD so I was not expecting this. I went down to the local hot rod shop and got them to make up a replacement for the coil wire which resulted in much improved operation! However, I now have a level of mistrust with the IPD wires. While trolling the RockAuto site I discovered that they had a set of the Bosch plug wires for the B20 and were clearing them out for $11.99 Cdn $. There was only one set left so I snapped it up.

While trying to trace the source of the misfire, I noticed that my ignition timing seemed to be retarded by about 5-6 deg. This surprised me as I had done a static check last year when I checked the valves. Perhaps the advance mechanism had been stuck, anyway I went through the whole process of resetting the timing on a running engine as per the service manual. I was having problems getting the idle speed down to the required 800 RPM. Checking the aux air valve from the top indicated that it was closed; however, on reconnection of the hoses you could feel that there was a slight leak through the valve even though the engine was fully up to operating temperature. I had to block off the inlet to the valve to get the idle speed down to 800 RPM. I did recheck the aux air valve after driving around a bit because my newly reset idle speed (after checking the timing) seemed low. I discovered that the valve was now fully closed messing up my idle speed setting. The valve movement must be sticking a bit in the close to closed position. The writing may be on the wall for the aux air valve and I may have to consider installing an idle air valve controlled by Megasquirt. I was thinking about either the 2 wire Bosch idle air valve form the early 90s B230F engine (less expensive) or the later 3 wire Bosch valve which I think was used on the 850 Volvos (more expensive). Does anybody have experience with using these idle air valves with Megasquirt?

With my ignition issues sort of resolved, I wanted to get back to addressing my fueling issues. I had noticed that when I was using the tune analyze live function in Tuner Studio, sometimes it would plug in very low Ve values in the cells around 30 – 40 kPa and 3000 RPM which seems to correspond to an urban cruising speed. If I accepted the Ve values, sometimes the AFRs would be OK when operating out of those cells and then sometimes the AFR would go way off target and I would be maxing out on the EGO correction when operating out of the cells. Either my wideband O2 controller was giving flaky results or something was happening with the fuel delivery. Since my AFRs held pretty steady at idle I was thinking that the controller was probably OK and that I had a fueling problem, leading me back to the fuel pressure regulator. The FPR is supposed to have a 1:1 compensation that drops the fuel pressure as the manifold pressure drops. With a base fuel pressure of 28 psi the rail pressure should drop to 19 psi at a manifold pressure of 40 kPa. To test the fuel pressure while I was driving, I hooked an old oil pressure gauge up to about 10 ‘ of 1/8 tubing, placed the gauge in the interior of the car and plumbed it into the port on the fuel rail that I use for pressure checking. I primed the fuel system, started the car and tested the gauge pressure with the regulator vacuum line disconnected to confirm that it was giving me 28 psi. I then did a little driving around. Little was the operative word as it only took about 1 block to discover that with a manifold pressure of 40 kPa the fuel rail pressure was around 23- 23.5 psi rather than the 19 psi it should have been at. This will result in about an 8% higher flow rate through the injectors than what MS is programmed for.

The Aeromotive FPR that I have is supposed to have a 1:1 compensation and a base pressure that is adjustable from 20 to 60 psi. If it is possible to set the base pressure at 20 psi this would imply to me that the regulator should be capable of regulating down to about 5.3 psi if the reference manifold pressure is 0 kPa (I know – impossible from a practical perspective). Based upon the pressure measurements that I was getting at low manifold pressures, I was somewhat suspect about the ability of the regulator to control fuel pressure at low pressures. As an experiment, I decided to try the regulator with a base pressure set at 36 psi (the base pressure of the Datsun 280 ZX regulator). This required that I adjust the fuel flow rates programmed in Megasquirt for the higher operating pressure (fuel flow goes up as the square root of the new pressure divided by the old pressure). I started the engine and with the pressure reference disconnected, adjusted the FPR to provide 36 psi. I then reconnected the reference line and when for a spin while monitoring the fuel pressure and the manifold pressure. I printed out a little table of the fuel rail pressure versus manifold pressure for a 1:1 correction.



This table was calculated using the atmospheric pressure on the day I did the tests which happened to be just slightly over 102 kPa.
The test showed that with the base pressure set to 36 psi, the FPR seemed to be able to accurately correct the rail pressure for the change in manifold pressure, at least down to about 30 kPa which was as low as I could go for manifold pressure while driving around. At 30 kPa the fuel pressure was reading somewhere around 25 – 26 psi and the theoretical value is 25.56 psi. The transient performance of the FPR is a bit slow when dropping pressure which causes the AFRs to drop below target; but, I can live with that. The higher operating pressure also seems to have completely eliminated any of the chatter that the regulator was making before. The take away is that after some money and a whole bunch of time and frustration, I am now back to where I was about 14 months ago with the Datsun 280 ZX FPR! I do have a slight bit more knowledge about FPRs that I will probably never have to use again.

When I ditched the Datsun regulator last year, I was concerned that the higher fuel pressure and flow rates might make the injector pulse widths too short at idle, leading to unstable idle problems. When the fuel pressure was at 28 psi, my idle injector pulse widths were around 2.9 mSec. With the base pressure set at 36 psi they have dropped to around 2.6 ish mSec which should not be a problem. Right now, I am using an assumed time of 1 mSec for the injector turn on time. At some point, I may have to do a little test to see if I can measure the actual turn on time for the Bosch injectors.

I have noticed that I have always had a slight bias in terms of reported AFRs between what Tuner Studio was showing and what my dash gauge was reporting. The default analog outputs in the Innovate LC1 O2 controller are 0 v – 7.35 AFR and 5 v - 22.39 AFR Which matches the set up of the Innovate dash gauge that I have.. However, the default setting for the LC1 in Tuner Studio seems to be 5 volts – 22 AFR. This isn’t a huge difference; however, I did reprogram Megasquirt with custom settings using the numbers from Innovate which seems to have brought the dash gauge and Tuner Studio closer to the same AFRs. However, this now means that O2 correction has increased because the Ve tables were set up with the default LC1 settings.

With the new fuel pressure settings and revised O2 controller curve, I am going to have to spend some time driving around with Tuner Studio on. I am going to use the auto analyse feature; but, not let it update the controller. Rather I will manually transfer the Ve settings that Tuner Studio generates that look reasonable.

[142 Guy]

I was in contact with Aeromotive's tech support about my fuel pressure regulator issues. Their opinion was that the failure of the regulator to track the manifold pressure at the lower 28 psi base pressure was due to the back pressure on the regulator caused by the use of a 5/16" return line. Their recommendation for the minimum return line size is 3/8". Increasing the base pressure to 36 psi moved the regulating range up far enough that the back pressure on the return line had less effect on the regulator operation.

Given that the D jet and Datsun 280 ZX both used 5/16" return lines, I wasn't really expecting back pressure to be an issue; however, given the noisiness of the Aeromotive regulator caused by using a sharp 90 deg elbow on the discharge, my conclusion is that the FPR is quite sensitive to back pressure. I am going to stick with the higher operating pressure and 5?16 " line for now since it seems to be working OK. If I get desperate for things to do, I may change the line size. Perhaps it might improve the transient response of the FPR.

[142 Guy]

Just when I thought I was pretty much past my fuel pressure control issues, I noticed that I was again starting to get some howling noises from my FPR on occasion and my AFRs would briefly wander around a bit. Aeromotive recommends a minimum return line size of 3/8” for the regulator I am using and it was apparent that the regulator is sensitive to back pressure on the return line. I thought that jacking the base pressure up to 36 psi had minimized the effect of the back pressure; but, apparently not. I am still not sure why this problem with the regulator only shows up sporadically. I gave consideration to plumbing in a new 3/8 “ or larger return line to see if that would address the problem, which was going to be a fair amount of work. Instead, I decided to retry the Datsun 280 ZX FPR that I originally started out with; but, abandoned because I didn’t like its high operating pressure of 36 psi. However, I figured if Nissan could make the FPR work on the 280 ZX with the same 5/16” supply and return lines that the D jet had, it should work on the Volvo.

I reinstalled the FPR with a slightly more sanitary mounting than I previously had, attempting to minimize any sharp bends in the supply and return lines. I checked the pressure and determined that the base pressure was actually more like 38 psi according to my gauge rather than the 36 psi which I believe is the design value for the 280 ZX . I reprogrammed Megasquirt to work with the higher injector flow rates associated with 38 psi versus the 36 psi that I had moved to back in August with the Aeromotive regulator. I also checked the compensation of the regulator for manifold pressure. With the fuel pressure gauge hooked up and the engine running I was able to get fuel pressure measurements at three different manifold pressures. They were:

MAP / Fuel pressure
100 kPa / 38 psi (engine off)
72 kPa / 34 psi
40 kPa / 30 psi
35 kPa / 29 psi

The compensation is off a bit, running about 0.5 psi higher than the theoretical values. Probably well within the ability of the EGO to correct. I also have no sense as to whether this is normal or subpar performance for compensation control on FPRs. I wasn’t able to measure the transient response of the FPR which would be interesting.

I have been planning to implement spark control and make the move to sequential fuel injection, primarily in the interest of improving idle and transient performance, and also, ‘just because’. To this end, I have ordered a Yoshifab adaptor drive for a Mitsubishi style cam angle sensor which will provide both the #1 TDC position signal and the engine speed signal. I also ‘pick and pulled’ some COPs off of a wrecked 2003 Corolla for the ignition. The Toyota COPs are nice because they have the driver and dwell control built right into the coil. The coils are controlled by logic level signals out of the Megasquirt. I picked up the four of them and the associated wiring harness for $35. I had consider using some of the GM LS series coil near plug coils which also have built in drivers and dwell control; however, the only GM late model truck in the yard was pretty well stripped out so Toyota it was.

As an interesting side note, while I was wandering the import car section of the pick and pull looking for parts, I noticed that most of the cars had there fuse box covers pulled and the fuses removed. Not relays, just the fuses. I asked the guy at the checkout about it and he said that there were one or two guys who regularly came in every few weeks and harvested the fuses out of the cars. He had no idea what these guys were doing with all the fuses they collected. Talk about a low value item to collect!

If you have followed this thread from the start, you may recall that I have a mix of injectors on my car. Two of the original Bosch 280 150-036 injectors and two of the Beck Arnley 158-0438 Which B A sells as a replacement for the Bosch. I decided that it would probably be good to have a set of four matched injectors if I was going to try sequential fuel injection so I ordered another two of the B A injectors from Rock Auto (at about 1/3 the cost of the replacement Bosch parts).

I also decided that I should probably attempt to verify the flow rates on the B A injectors and attempt to estimate the injector dead time and the sensitivity of the dead time to the supply voltage. To this end, I set up a test rig connected to the car. I fabricated (more like nailed two pieces of wood together) a jig to hold one of the new injectors in place over a graduated cylinder for measurement. I attached my fuel pressure gauge to a T directly above the injector. All of this sat on the ground in front of the car and was connected to the old cold start injector port on the fuel rail with 5 ft of 5/16 fuel line. For the short pulse width tests, I used a 25 cc graduated cylinder for the flow measurements (improved the low volume accuracy) and a 50 cc graduated cylinder for the longer pulse widths.



I connected the injector electrical terminals back to one of the injector plugs with about 5 feet of 16 awg zip cord. All of the injectors on the car were unplugged. I also unplugged the O2 sensor and disconnected the ignition coil. I used the Megasquirt fuel injection controller in injector test mode to deliver a series of 400 test squirts on the injector using the cars fuel supply system running off of the car battery with a battery charger connected. However, I did not run the test injector off of the car battery. I ran the injector off of a separate regulated DC power supply. This allowed me to hold the injector supply voltage steady during the tests and also allowed me to do the tests with different injector voltages so that I could characterize the voltage sensitivity of the injectors. I connected a digital voltmeter directly to the supply resistors for the injectors so that I could confirm the supply voltage at the point where Megasquirt would measure the supply voltage.





I did the most extensive test sets with the injectors operating at 12 v and 14 v taking samples over a range of pulse widths varying from 0.75 ms up to 14 ms with more data points collected in the 2 – 7 ms range because that is where the B20E (at least mine) operates. I did a few tests with injector voltages of 10 volts and 16 volts just so I could confirm the voltage sensitivity of the injectors. All of my tests were done using the cars fuel pump and supply / return piping with a fuel pressure of 38 psi as the 280 ZX FPR has no provision for adjustment. The injectors were fired through the 6 ohm , 1%, 50 W current limiting resistors I use with the Megasquirt (same resistance as used in the Bosch Djet controller) plus the associated resistance of the cars wiring harness. Since the injectors were characterized ‘on the car’ as opposed to a standardized test rig, the results may not be exactly the same as a standardized test set up. The fact that I am using resistors that may be on the smallish size (ohm wise) may result in fairly high peak injector currents which might explain the rather short opening times that I got (more on that later). I did the tests with an ambient air temperature of around 6 C. I make a point of noting the resistance, resistor wattage rating and ambient temperature because the test results indicate that the injector opening times are quite sensitive to operating voltage. If you are using different resistors or the resistors are heating up during the test, it will alter the opening times and the results, particularly at the smaller injector pulse widths that I was interested in. If all you were doing was a gross estimate of the average injector flow rate over a period of perhaps 5 or 10 seconds, then this would not be an issue.

For the Beck injectors, I did 3 or 4 tests at each pulse width. The measurement results showed excellent reproducibility between the test results with most of the variance probably resulting from the ability of my eyes to determine the fuel level of each sample in the graduated cylinder. It also turns out that my garage floor is no longer level which complicated reading the graduated cylinders when I put them on a table. The Bosch Motorsport injector data sheet claims a flow rate of 48.19 lb/hr or about 492 cc/ min at a test pressure of 43.5 psi. Correcting for my 38 psi test pressure I expected that the flow rates should be around 460 cc/min. I was expecting something similar for the Beck injectors; however, a preliminary check of the gross flow based on some of the longer duration pulse widths showed that the injector flow rates were more like 480 – 500 cc/min without consideration of the injector opening time.

One of the things I noted during the test was that the pressure gauge was fluctuating slightly between about 36 and 38 psi. This was not obvious on the short duration tests; but, materialized with the longer pulse widths. This had not been particularly noticeable when the pressure gauge was connected directly to the fuel rail and the engine was operating at idle (2 squirts alternating). However, at idle the pulse widths are short so it may have been present; but, not visible. It might also be the result of the 5 feet of fuel line that I used to connect the test rig to the cold injector port on the fuel rail. So, a word of caution, my test results may be for a fuel pressure of 36 psi instead of 38 psi or something in that range. While we are on the question of fuel supply, if you are using the Megasquirt injector test mode for doing the tests, do not rely on the Megasquirt to energize the pump during the test. I found that with my regulator and pump arrangement, there is enough relaxation in the fuel pressure when the pump turns off that I would not get consistent test results on short duration injector operation unless I manually started the pump before doing the test. If you were doing a long duration flow test this would probably not be an issue.

When I completed the test on the new Beck injector, I then removed the two remaining Bosch injectors on the car and replaced them with the new Beck injectors. Since I had a little time, I decided to try doing a quick test to characterize the flow on the Bosch injector. Because the remaining time was limited, I only did a 14 volt curve and I only did a single sample for each injector pulse width. Because the Bosch 14 V test was done after I completed the Beck 12 V test, the DC power supply had been adjusted and may not be at exactly the same voltage as the Beck 14 V test; however, it would be within +/- 0.1 volt of the Beck test voltage.

First off, I have attached the raw test measurements for both injectors for anyone who is interested. The columns on the far right are the gross fuel measurements for each injector test (the sum of 400 squirts). In the case of the Beck injectors they are the average of the 3 or 4 test measurements. For the Bosch injector they are the single test result. The columns on the left are the calculated values of flow per injector pulse (essentially the gross flow divided by 400). Note that the values are 10-3 ml. So, as an example the Beck injector delivered 0.080 ml for a 10 ms pulse which averages to (60s/min x 0.080 ml/0.010s) 480 ml/min (without consideration of injector opening time).





I plotted the gross fuel delivery measurements for the Bosch and Beck injectors for the 14 volt test results for pulse widths up to 6 ms. I have attached the curve. The test results show that between 2 and 6 ms, the Bosch and Beck flow data lie on pretty much the same curve. The flow on both injectors becomes non-linear at pulse widths below 2 ms with the Beck dropping off marginally slower than the Bosch. This latter effect could be the result of the fact that the Beck was brand new and the Bosch was 30 + years old rather than a characteristic of the injector itself. The injectors display good linearity over the 2 – 6 ms range and could probably operate acceptably down to pulse widths of 1.5 ms. I estimated the average flow rates of both injectors based upon the slope of the flow curve between 2 and 6 ms. Rather than do something like a least squares fit, I just used the actual data points for 2 and 6 ms since the ‘curve’ data points don’t have a lot of scatter. For the Bosch injector the flow rate is 519 ml/min and for the Beck it is 514 ml/min. Significantly higher than the expected flow rates of 460 cc/min (Bosch published data corrected to 38 psi operation). Back in 2011, a member on the Turbobricks forum reported that his cleaned and tested Bosch 280-150-036 injectors came back at 570 ml/min @ 43.5 psi. Adjusting the 519 ml/min 38 psi flow rate for a pressure of 43.5 psi would give a flow rate of 555 ml/min. If in fact my test pressures were 36 psi (referring back to my notes on the pressure gauge fluctuations), then the adjusted flow rate for my test would be 570.5 ml/min, jiving exactly with the previous results posted by the forum member. Clearly the injectors flow much more than Bosch’s published data.

What is really interesting is that if you visually extend the flow curves in a straight line to find where it intercepts the X axis, you will get crossings somewhere below 0.2 ms, which would be the nominal opening time for the injectors using a linear flow curve. If you use the slopes I calculated and the data point at the 2 ms pulse width, you can back calculate where that line intersects the X axis which would also provide an estimate of the injector opening time for the injectors linear operating range. The Beck intersects the line at a calculated value of 0.0152 ms and the Bosch at 0.0150 ms. 0.15 ms would be a good estimate of the opening time for the injectors at an operating voltage of 14 volts.



Megasquirt is programmed on the basis that the injector opening time is defined at 13.2 volts so you need to adjust the opening time for an operating voltage on 13.2 volts. In order to do that, you need the sensitivity of the injector opening time versus operating voltage. That is what I used the Beck Arnley test data at 10 V, 12 V and 16 V for. My calculations were based on the test data at 2 ms and 10 ms because those are the only points I had for 10 V and 16 V operation. I calculated slopes and Y intercepts for the 10 V and 16 V data using the 2 data points that I had and did a least squares fit for the data range of 2 ms to 10 ms for the 12 V and 14 V data set to get the equivalent slopes and Y intercepts. Using these curves I calculated where the curves would intersect the X axis (zero flow)

10 volts 0.606 ms
12 volts -0.22 ms
14 volts -0.01 ms
16 volts -0.076 ms

Note that the 14 V X intercept calculated here does not match the values I calculated previously. That is because the slope for a least squares fit on the 2 – 6 ms data set is not the same as the slope for the least squares fit between 2 – 10 ms. The flow curves are close to linear but not quite linear and small changes in the slope can make a big difference in where the X intercept lies. Since you are attempting to linearize what appears to be a non-linear curve, it is important to linearize it over the expected operating range of the engine. If these injectors were operating at much larger pulse widths than what I am using on my B20E, I expect that the derived injector dead times would be different.

Using the preceding data, the voltage sensitivity of the injector opening time is as follows:

12-10 volts 0.19 ms/volt
14-12 volts 0.12 ms/volt
16-14 volts 0.03 ms/volt

The sensitivities are positive values since they add to the opening time as the injector voltage drops. As you can see and as many other sources report, the opening time versus voltage relationship is highly non-linear. I redid the calculation and calculated the injector opening times that would correspond to a flow of 20 ml/ms for the four different operating voltages. These values for voltage sensitivity came out at:

12-10 volts 0.19 ms/volt
14-12 volts 0.12 ms/volt
16-14 volts 0.02 ms/volt

If you change the data sets to calculate the least squares fits using the data set from 6 – 2 ms for the 12 V and 14 V tests, you will again get slightly different results. At a flow rate of 20 ml/ms, the calculated 12 – 10 V and 14 – 12 V sensitivity range is very close to the preceding results (0.20 ms/volt and 0.11 ms/volt); however, the 16 – 14 volt value is significantly different. Since Megasquirt only has provision for a single value for voltage sensitivity, I am going to use the sensitivities that correspond to the 14 -12 volt operating range which is where my car is usually running. All the calculated values suggest that 0.12 ms/volt is a reasonable value to use for this operating range. As a note, this applies only to the Beck Arnley injector since I did not do any voltage sensitivity measurements for the Bosch injector.

With a value for the voltage sensitivity, you can calculate the expected opening time for the injectors at 13.2 volts. Given that the inferred opening time at 14 volts is 0.15 ms, the inferred opening time at 13.2 volts would be:

0.15 ms + (14V – 13.2V)x 0.12 ms/volt = 0.25 ms (rounding up)

I concentrated my work primarily on the injector operating range below pulse widths of 8 ms. I did take some measurements up to 14 ms pulse widths. The Bosch seems to maintain a relatively linear flow relationship over the whole 2 – 14 ms range. However, the Beck Arnley measurements at 12 V suggest that the flow curve is turning upwards around 10 ms. I only have two values at these larger pulse widths and nothing for 14 V operation to allow a direct comparison to the Bosch. The caution here is that if the Beck injector is showing significant non-linear behaviour above 10 ms pulse widths, the flow rate, dead time and voltage sensitivity values that I have calculated would all be out to lunch. If you are thinking about using the Beck injector at pulse widths above the 8 – 10 ms range, you would certainly do well to characterize it in this higher flow range to confirm or refute the results that I got.

[tmtalpey]

Wow, I'm going to have to plan some time to come back and read this. But I have one quick question, with all this precision, do you see any effect of lower fuel temperature, this time of year? It's my understanding that modern injection systems pay quite a bit of attention to it.

[142 Guy]

To paraphrase my statistical methods instructor, there may be a lot of precision; however, I don't know how much accuracy !

In terms of temperature effect, are you talking about the effect of fuel temperature on the flow rate of the injectors? I didn't measure the flow rates at different fuel temperatures so I can't advise. However, from what data I could find, the viscosity of gasoline does not go through a huge change over the typical operating range, so that might not be an issue.

I do know that the density can have a significant change. The same volume of gas weighs about 7.5% more at -30 C than it does at +30 C. If you had set up your fuel injection system to run at +30C, you would be delivering about 7.5% more fuel (mass wise) at -30 C because the fuel injection system is metering fuel volume, not fuel mass. Once the engine is running and up to temperature and goes into closed loop operation with the O2 sensor, I would think that fuel trim would be able to fix that and bring operation back to 14.7:1. However, a full load or when cold the engines are typically open loop. If the emission standards are tightening up, the vehicle manufactures may be doing some fuel temp compensation to allow them to get more accurate metering during those transient operating periods. That is all a guess on my part since Megasquirt does no fuel temp compensation and I am not aware of any systems that do it.

[142 Guy]

A little bit of tuning and I have had to really increase the values in the Ve table to deal with the higher flow rate data that I have entered for the injectors. I will post a before and after Ve table when I get some more cells populated with numbers based upon actual operation.

An interesting effect of the 0.25 ms offset is that when lifting off the throttle at the end of an acceleration run, I was getting into super jerky operation and seeing wild swings on the AFR. This problem did not show up when I was using an injector offset of 1 ms. I had my deceleration fuel cut set at 25 % and a log showed that the PW was dropping to 0.70 ms or less on lifting the throttle. With the .25 ms injector offset, the sum of the offset and the calculated PW would be around 1 ms and the injector is definitely running into the non linear area of operation (fuel was probably getting close to completely shutting off if the applied PW were dropping into the 0.7 ms range). I cranked the fuel cut to 50% and then 60% and that seems to have fixed the problem.

The ideal situation would be to reduce my fuel pressure down to something like 30 psi which would increase my pulse widths and hopefully keep the injectors out of that nasty non linear region. However, until I can get an FPR that works with a lower base pressure I am stuck with the Nissan FPR at 38 psi.