I know this topic has been beat to death but I have a bit of a unique situation I’m hoping someone can help me with. My car (‘90 325i) starts and runs beautifully for about 15 seconds when cold then immediately begins idling rough, hesitating when accelerating, and is down on power. I was driving home from work when it all started, going about 20mph in traffic and I swear I heard a “click” then it went south. Although the click could have just been in my imagination... No CEL but it was obviously acting up.
The entire engine has about 10k miles since getting a top to bottom reseal and reconditioned head. It also has about 25k on refurb’d injectors, and has new spark plugs, newer O2 sensor, cleaned CPS, and swapped AFM with known good unit. I did the plugs when It started acting up and 2-6 looked great, #1 was a little black compared to the rest but not terrible. I thought the plugs did the trick but in the time it took me to move my other car out from in front of the garage door it started acting up again. Compression is 175-180 across the board. I’ve also cleaned the big plug under the intake, and checked for fuel in the FPR vacuum line and it’s fine. I don’t think it’s O2 since it happens at idle and when it still is cold. I don’t think it’s the ICV since I’ve had those act up plenty of times and it doesn’t seem like this, and that wouldn’t matter on throttle/WOT. I don’t think it’s the TPS because it occurs at idle, part throttle and WOT.
My plan is to bring home a fuel pressure test gauge tomorrow, just to rule that out. I’m looking for advice on where to go next. While unplugging everything under the sun to look for clues I noticed my CEL comes on but goes off immediately. Does that indicate a ECU issue? I can’t remember if the code should be stored... anyway, any help is appreciated. Thanks
The entire engine has about 10k miles since getting a top to bottom reseal and reconditioned head. It also has about 25k on refurb’d injectors, and has new spark plugs, newer O2 sensor, cleaned CPS, and swapped AFM with known good unit. I did the plugs when It started acting up and 2-6 looked great, #1 was a little black compared to the rest but not terrible. I thought the plugs did the trick but in the time it took me to move my other car out from in front of the garage door it started acting up again. Compression is 175-180 across the board. I’ve also cleaned the big plug under the intake, and checked for fuel in the FPR vacuum line and it’s fine. I don’t think it’s O2 since it happens at idle and when it still is cold. I don’t think it’s the ICV since I’ve had those act up plenty of times and it doesn’t seem like this, and that wouldn’t matter on throttle/WOT. I don’t think it’s the TPS because it occurs at idle, part throttle and WOT.
My plan is to bring home a fuel pressure test gauge tomorrow, just to rule that out. I’m looking for advice on where to go next. While unplugging everything under the sun to look for clues I noticed my CEL comes on but goes off immediately. Does that indicate a ECU issue? I can’t remember if the code should be stored... anyway, any help is appreciated. Thanks
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