04' S60R new to me. P0234. Overboost.
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    1. #1

      04' S60R new to me. P0234. Overboost.

      Hello. New to the forums. Hopefully this is the right place to post. I bought a 216K mile 04 S60R. It is a fixer upper. I'm a Ford Mustang cobra guy and never owned any Turbo cars I've began to investigate, research and attempt to diagnose the p0234 overboost condition. I bought it last Monday and brought it home seemingly in limp mode since then. I don't have $$$ to start throwing at it right this second so I went to the picknpull yesterday and I swapped in another TCV from a volvo to see if that made a change. Along with a battery reset it began to produce boost upon driving. 5 -10 miles later it started to run poorly again. I brought it to my friends house whom has a little knowledge of Turbo cars and we began to datalog using his obd2 reader and phone app. It works well and shows practically all engine parameters. On repeated test drives we would see the car go from hesitating with low power struggling to produce boost, to boost spikes of 15-30 psi. We began to learn the wastegate adjustment procedure and check vacuum lines. The line to the actuator is free of leaks and holds vacuum. Attempted with an air pressure setup to determine what psi the actuator rod began to move, but my setup was too inconsistent to determine so we "lengthened" the actuator rod in accordance with one of the IPD demo videos to see if this would cure the overboost. I put the adjuster almost all the way to the end of the last threads on the rod. This has made the car perform night and day better but we still saw 30 psi boost spikes according to the details. It feels like it is no longer struggling or going into limp mode, but I'm concerned that this was just a bandaid for a different problem and I don't want to blow the motor. I'd like the engine running 100%. One thing I did notice is that the Red striped line from the TCV that goes to the Turbo allows air to pass when you blow into it. Air can be heard moving in or around the turbo. My question is whether that is supposed to be happening. Could my problem be a bad wastegate actuator? Other turbo component? Boost psi sensor? Maf? Bad ECU? Boost leak in ducting or inter cooler cause this? Ignition? Exhaust? All help is greatly appreciated.

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    3. #2
      Junior Member
      Join Date
      Mar 2015
      Northern Iowa
      Are you using an actual boost gauge? Just an FYI on these cars the number in the ECU is calculated not measured.
      10/04 Volvo V70R, 6spd. 187k. Kaplhenke subframe bushings, Snabb turbo intake, Forge CBV
      '94 BMW 325i Sedan, Arctic Gray: 238k, mid restoration.
      '85 Toyota LandCruiser: Lifted, gas hog. 202k
      '99 Nissan Maxima: 5spd, Rusty but trusty winter beater. 250k

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