Help! XC90 Struggles to Accelerate

[VikingSpeed]

Alright Swedespeed, I am hoping you can come through and give me help once again!

2007 XC90 3.2 Awd with 122k miles

Back story:
I Replaced the X-pipe (which contains down stream O2 sensors and secondary cats) because the flex pipes were rusted through and mid muffler last weekend. Took it for a test drive and everything was great. My wife drove to work and home on Monday with our little one on board...and the XC90 threw a whole bunch of new issues at me which do not appear to be related to my repairs last weekend.

Current Issue:
I have been trying to diagnose this since Tuesday, the vehicle will accelerate normally with light throttle at low speeds, but as soon as the rpms get above 2500 the vehicle struggles to accelerate. If you jab the throttle to get it to kick down a gear and accelerate faster the transmission will drop a gear but the rpms struggle to climb. You can hear the intake sounds get deeper as it try's to get more air in the engine, but the rpms climb slowly and not smoothly. Feels like a stutter/misfire...I am not sure if one thing is causing and issue or multiple things.

Here are the codes pulled from Vida on Monday


The bottom codes for the manifold runner control (morning code) and misfire's (evening codes) are the new codes, the catalyst efficiency is from before I fixed the exhaust. Here is the timeline info


Here is the freeze frame from when the Intake manifold code was set



Here is the freeze frame for the misfire codes, since those 3 codes were set at the same time they all have the same images captured




I have since tested the operation of the Upper Intake manifold runner control through the activation's in Vida, I could hear and feel it open and close just fine. I could not get it removed to visually see it work. I also removed the coils from cylinder 1 & 3, coils are original and visually look Ok. I also checked the spark plugs for those cylinders and they still look new (replaced a year ago). I did swap cyl 1 & 2 coils to see if the codes would change. I disconnected the battery to reset things, I have gone on several test drives, 10-15 minutes at a time. No codes have popped up but the car still struggles to accelerate.

I took a graph screen shot in Vida of the MAF(mass air flow) and throttle postion. Gentle acceleration the 2 moved in unison on the graph. This picture is when I jab the throttle to kick it down a gear and try to accelerate, you can see the throttle opens and the MAF goes CRAZY! Is this normal to see for a MAF?


So I removed the MAF, clean it and reinstalled it. I received the same results. I unplugged the MAF and the car stalled. I restarted it and it had a very lumpy idle. I drove it and experienced the same struggling of acceleration.

So I ran another graph, this time showing MAF (blue), Throttle position (black), Fuel Pressure (red), Intake manifold pressure(green), and Fuel pump duty cycle(purple)
Here is a graph of very light normal acceleration, everything appears to be good...


This one shows deceleration and then a jab of the throttle again to accelerate. Throttle position goes up, Manifold pressure goes up, MAF is crazy again, fuel pressure didn't really change, the fuel pump duty cycle dropped during deceleration and came back up on acceleration.


Another shot, similar driving scenario, similar results



Anyone have any idea what's going? I have been scouring the internet all week for answers. Everything I have read any of these things could be the issue..bad MAF? Bad Coils? Bad intake manifold runner control? Bad Throttle Body? Vacuum leak? Bad thermostat causing the head to get hot and ruin the coils? Bad Fuel Pressure Sensor? Bad Pem? Bad Fuel pump? Crankshaft position sensor? Cam solenoids?

I will add no additional codes have popped up yet, even though it drives so poor. The Short term and long term fuel trim appear to be within range as do the O2 sensors.

My wife and I have been car pooling all week in the VR, but I need to get the XC90 back on the road ASAP
Thank you for your help!

[bblake12]

I am not an expert but that mileage was about the time I had a coil go bad. Engine would stutter on acceleration. I replaced them all but it damaged a cat and I now have a permanent check engine light. I am now onto 226000 miles on my 07 without issue. Planning on changing my coils again soon.

Sent from my LM-G820 using Tapatalk

[ChitownV]

Great information and presentation in trying to explain things.

It sounds like you are leaning towards a hunch it is the MAF. It could very well be and I am no expert in reading different MAFs and it has been 15 years since I last used an oscilloscope on a MAF. I do remember the erratic nature of bad MAFs, but MAF graphs can also depend on the electronic throttle position programming.

Before ordering a new MAF insert, also change cylinder #3 coil with #6 and see what happens. So, you can also see if you will need any coils.

Problems like this happen all the time when you replace one part. The reason could be as simple as using the vehicle more and parts that are going bad finally break. Your mileage is within the normal range of wear parts to start popping up.

[Hong Kong]

Measure also fuel pressure and when is the last time that you changed fuel filter? Also fuel control module can cause similar problems. Hidden under rear right wheel under splushing material. Maybe different on your car. We talked about this module here will find a post.

1. Change fuel filter first if never changed than we see if change something.
2. i have almost 14 years coils original and changed only 1.

This problem can be also bad harness connectors Pin oxidation on coils - i changed all cables last year and solved.

Now its time for O2 sensors. Both.

Please try first with fuel filter and report. 10 min you need to change it. 10-15 min max.


Sent from my SM-G950F using Tapatalk

[Hong Kong]

Cam VVT solenoids dont made such a problem.

I had bad connector pins on new cables afyer i changed all harness they simply pop out wire from bad crimped pins and car pulling normally.

Sent from my SM-G950F using Tapatalk

[bblake12]

Measure also fuel pressure and when is the last time that you changed fuel filter? Also fuel control module can cause similar problems. Hidden under rear right wheel under splushing material. Maybe different on your car. We talked about this module here will find a post.

1. Change fuel filter first if never changed than we see if change something.
2. i have almost 14 years coils original and changed only 1.

This problem can be also bad harness connectors Pin oxidation on coils - i changed all cables last year and solved.

Now its time for O2 sensors. Both.

Please try first with fuel filter and report. 10 min you need to change it. 10-15 min max.


Sent from my SM-G950F using Tapatalk

Agree on fuel filter literally took 10 minutes and didn't have to lift car. Fuel will spill though so watch the videos.


Sent from my LM-G820 using Tapatalk

[Hong Kong]

I will suggest fuel filter first. Repeat many people forget years to change it. Years litteraly over 5 and more...last one that i know the guy get so funny offers from mehanics to even change sparks ignition coils ect ect 1200 euro and was only cloddged never changed 8 years fuel petrol filter. In some countries as Serbia they sell crap bad dirty mixture of oils water un petrol ect ect...

Sent from my SM-G950F using Tapatalk

[Hong Kong]

1 bolt 10mm and push 2 clips button on hoses but before you do push valve to release pressure. use and cover with cloth to not spill petrol in face or floor.
Bear of direction arrow.

The small filter is used in line just to show how dirty is petrol here. This was accumulated in less than 3 months. Of course fuel tank can be after years also full of dirt but anyway this is prove. Many old petrol stations have rusted inside and brings dirts directly to our tanks.

Sent from my SM-G950F using Tapatalk

[Capndirk]

The fuel filter on my car hadn't been changed, so I did it for PM at 90k. I was surprised at the instructions in VIDA, which I checked for grins. It said to run the engine and then pull the fuel pump fuse until it dies! Then change the filter as Hong Kong says above. Then, refit the fuse and you're done. I don't know for sure, but it may have made the job cleaner. I was a little disppointed that there wasn't some kind of reset in VIDA for the job
Then, when draining the filter from the inlet, there was some real serious dreck coming out. That surprised me for a US operated car. I thought all US fuel stations would filter their delivery stream.
Also, my average mpg improved immediately, and the cat converter stink going up hill abated, too. That was actually one reason I changed it, as another poster had said that the stink went away after changing the fuel filter. I was definitely skeptical about that, before.

[Hong Kong]

No body filter on petrol stations fuel. No one. There is NO huge filtration system at all.
Second I change filter regularly as I also first time feel huge difference in pressure of course.

As you mention dont worry about few drops of petrol when you removing filter. Just push valve
to release pressure. Its there for this reason. Few drops of petrol from hose and if you use
cloth around and with finger close both sides of old filter very small petrol will pop out.

So simple to change. Im glad to read also your experience with. Forget Vida for such a simple job.

[VikingSpeed]

I replaced the original fuel filter about 4 years ago. Yes it is easy to do, however I don't think it is the issue. I did order a new MAF and 6 new ignition coils and have installed them. My MAF reading with the old one was lower at idle from what VIDA said they should have been. I can say with the new MAF that my readings at idle are now where the should be.

I was finally able to remove the upper intake manifold runner control actuator and confirm that it is working properly (no binding, grinding, or weird noises). I also tested the throttle body actuation through VIDA, the ouputs said it was working and the values were matching, but it was really noisy while moving. It was making high pitched electronic motor noises, not sure if that's normal???

So with the new MAF and 6 new coils installed......I went for a drive and still have the hesitation to accelerate. So when accelerating the intake makes some very deep noises like its trying to suck a watermelon through a straw....Currently I am leaning toward there being a vacuum leak somewhere in the intake. Good news is there aren't too many hoses or connection points to check, but I don't have a smoke machine to test with.

Here is a link to the Intake Manifold https://www.volvopartswebstore.com/s...rimLevel=24666
Anyone know if #14 is a common failure item? It is listed as a Vapor Canister Purge Solenoid https://www.fcpeuro.com/products/vol...60-s80-8653857

[ChitownV]

Good work! This could be more than just one part, but a collection of parts that have worn over time. Just for sh**s and giggles, did you try to remove the dipstick while the engine is on to see if you could hear any vacuum noise...indicating the PCV needs replacement? At 122k miles, it could very well need replacement whether it is causing major issues with the acceleration or not.

Having worked with other electronic throttle bodies, they can make that electric noise. The variable intake runners could contribute to the issue if they are not fully open or closed. If you slowly accelerate to a higher rpm, does it become smoother?

[VikingSpeed]

Good work! This could be more than just one part, but a collection of parts that have worn over time. Just for sh**s and giggles, did you try to remove the dipstick while the engine is on to see if you could hear any vacuum noise...indicating the PCV needs replacement? At 122k miles, it could very well need replacement whether it is causing major issues with the acceleration or not.

Having worked with other electronic throttle bodies, they can make that electric noise. The variable intake runners could contribute to the issue if they are not fully open or closed. If you slowly accelerate to a higher rpm, does it become smoother?

I replaced the PCV box on top of the engine last year along with 6 new Volvo Spark Plugs. The old pcv box was nasty and it solved some of my oil consumption issues I had. I will say that with the actuator removed the inside of the intake manifold that I could see looked fairly clean, no signs of excessive carbon build up.

Thanks for the info on electronic throttle bodies making noise. I will have to try slowly accelerating to higher rpms (this will require using manual mode on the transmission to hold the gear long enough), that would be a good test for the intake actuators.

[kiwiV8]

you've ruled out fuel, I'd check air next... also I thought the car with absence of MAF signal would fall back to some default profile so it'd run slightly rich.
When I do my ATF fluid exchange I often disconnect the air filter box, and if I leave the MAF connected it would stall, so I'd disconnect it.. and just wrap some cloths around intake so it's not sucking random crap into the engine.. hope your issue's resolved soon!

[VikingSpeed]

So I gave up on having the time and energy to look into this and took it to the dealership for repair. I shared with them all the information I have posted on here. I just got the call back from them and after 4 hours to diagnose it, they are leaning toward it being clogged/fail catalytic converters....which from Volvo are $2k each, and it would need 2 of them...Honestly I don't feel it is a failed catalytic converter, but I'm not sure what else to look at.

The mechanic tested compression and it was good.
He inspected the new exhaust I installed and put a scope through the new x-pipe to make sure no packing was stuck inside.
He tested the throttle body and it came back good.
They test ground wires, and the O2 sensor wires. All good.
They said I am getting fuel, spark and air...so that leads them to believe the the Catalytic converts have clogged
They also said it was throwing misfire codes and a code for the camshaft profile control, performance bank 1, intake A.....I will have to get a copy of the codes from them when I go pick up the vehicle

So I am not sure where this leaves me....find a second opinion? install new catalytic converters? (I can get them off rockauto for $280ea...replacing them would not be a fun job, I see broken bolts with that), sell the car?

[kiwiV8]

that sounds simple enough to verify right? disconnect the cat and it should at least accelerate fine(while polluting the earth)? If that's the case I'd just replace the cat and all it a day?

[John C]

They should be able to measure the back pressure in the exhaust system before the converters.

Probably totally unrelated, but mine would act like the throttle was disconnected (I know, it's electronic, but try to imagine it isn't) or would only open about 10% at random times on th first start of the day. When I replaced the steering angle sensor, the problem went away. (Actually, it's done it once in the last 2 years. Not loosing sleep over that.)

[ChitownV]

So, the one time I encountered a clogged cat in one of my cars, the car wouldn't just hesitate, it would sputter, mainly dependent on engine load, which was also related to rpms. If you blip the throttle in lower rpms or try to accelerate hard, does it sputter or hesitate? There is a difference, but the 3.2 has two banks of cats which could give a combined sputter/hesitation feeling if one cat is clogged.

However, now looking at all the information you provided in this thread, the only thing that changed before the running problem is the post-installation of pipes and center resonator. The original secondary cats/downpipe system does not have an X-pipe. It is a 2 pipe into the center resonator and then resonator goes into one.

Did you replace these all with aftermarket universal parts or an aftermarket bolt-on replacement? Seeing how your entire exhaust system was completely rusted, it isn't terribly out of question this could be a result of one bad primary/pre cats. If there was any restriction in the old exhaust and then you freed up flow, again, it wouldn't be out of the ordinary for the primary/pre cats on the manifolds to loosen up or fail internally.

[ChitownV]

that sounds simple enough to verify right? disconnect the cat and it should at least accelerate fine(while polluting the earth)? If that's the case I'd just replace the cat and all it a day?

The cat he is talking about is part of the exhaust manifold. It is one unit so it cannot just be disconnected and tested on a drive. Well, unless you want a no header engine spitting some fire into the firewall.