gdavenport Posted August 12, 2014 Report Share Posted August 12, 2014 All, I've been working through a bug that has my 2010 running rough. According to the codes, it had low starting fuel rail pressure (lift pump) and a cylinder misfire. I changed the plugs, and cleaned the injectors. The car is still running rough(rich?) and is showing 10"Hg (PID through the OBDII scan read). It smokes copiously, especially underload. I pulled the upstream O2s to check function in Open Loop and the car runs better, but still smokes. In closed loop, the fuel trims quickly run to -30 (maximum allowed) on both banks. What could be causing this? The OBDII ports show full function (sensors vary based on conditions) for: Throttle position(all sensors) MAP - varies between boost and up to 28"Hg, settles at 10 at Idle Fuel rail pressure (High side) varies from 65psi up to 1500 (maximum I can see at light/medium throttle) IAT reads through the range ECT reads through the range Does this sound like a mechanical problem or a faulty sensor? Quote Link to comment Share on other sites More sharing options...
mjhpadi Posted August 13, 2014 Report Share Posted August 13, 2014 What plugs are you running? Most of us have changed to the SP534 plugs gapped at .030. Don't know if that will help but it's something to consider because a fair amount of folks have discovered a big variation in plug gaps. As far as the others, don't have enough knowledge to give you any input. Quote Link to comment Share on other sites More sharing options...
gdavenport Posted August 15, 2014 Author Report Share Posted August 15, 2014 The engine has SP534 plugs in it already (it's not tuned). The issues are not related to the plugs or coils, I CAN say that. Running rich under load, however... Quote Link to comment Share on other sites More sharing options...
LindenBruce Posted August 15, 2014 Report Share Posted August 15, 2014 Any mods? Any trouble codes? B. Quote Link to comment Share on other sites More sharing options...
Crash712us Posted August 20, 2014 Report Share Posted August 20, 2014 @idle you should see 20-22 inches of vacuum. Do a compression test. I am thinking do to low idle vacuum the PCM thinks it's under a load and richening the engine. mjhpadi 1 Quote Link to comment Share on other sites More sharing options...
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