My setup:
Car was running like a dream for at least 500 miles: full throttle rips to redline, idled solid at ~1000rpm, stop-and-go traffic. But just this week had a strange stumbling issue while cruising at 65mph on the commute home. CEL went on, clutch in, and revs wouldn't drop, motor revved erratically...pulled over, saw no vacuum leaks (thought something was wrong with my intake install). Turned it off, then turned it back on, all was well. Made it home. Redid the intake thinking it was a vacuum leak. Test drove for 15 minutes, no problem. Next day, sitting at the freeway onramp, same problem started happening again. Thought it would clear up on its own (it did) so kept driving. Nothing out of the ordinary until 15 minutes later when erratic revving, CEL came on, loss of power with throttle. No strange metal-on-metal motor noises...tried to goose it off the freeway and it died. Cranked but wouldn't restart.
Thinking it was a wiring issue or some weird intake thing, had the car towed home. Double checked everything, all was good. But sitting in car with ignition on, I didn't hear the fuel pump prime...BINGO. Bad fuel pump or relay or wiring...so I pulled the two 4 prong main relays, jumpered each until I heard the fuel pump kick in (so the fuel pump was good). Here's the important parts: I left it jumpered, so the fuel pump kept running for at least 2 minutes. I also left the other relay removed (O2 heater, I believe). Tried to start the car and it ran like shit, sputtering, no power, lots of smoke out the exhuast and a loud intake backfire.
Shut it down and realized my stupidity probably flooded the motor. Pulled the plugs and they smelled like gas. Checked the oil and it didn't smell like gas. Replaced all the plugs with new ones, replaced all 3 relays (fuel pump, main, O2 heater) with new ones, tried to start it and same damned problem (sputtering, no power, smoke out the exhaust, backfire).
Thinking I completely broke the motor, I went to bed.
Pulled all those (new) plugs just now, they all look fine except three of them smelled a little bit of fuel. Motor turned OK by hand. Checked compression with open throttle, and it looks good (phew): 1-180, 2-190, 3-195, 4-195, 5-200, 6-195.
Before I try starting the car again, I'd like to hear your thoughts and suggestions. The rational part of my brain is telling me to throw in the towel and take it to someone with way more experience than I before I completely destroy this nice motor. I'm guessing:
Thanks in advance,
-Ernie
- 1990 325i
- S52B32 with full OBD-I conversion. ~80k miles, never rebuilt.
- S52 OBD-II exhaust manifolds with only one O2 sensor on front bank (soon will be moved to an x-pipe right before cats)
- S52 OBD-II mid-pipe
- Schrick street cams
- Lightweight flywheel
- 3.5" HFM (800)
- 24lb injectors
- TRM off the shelf 413 ECU chip to match above
Car was running like a dream for at least 500 miles: full throttle rips to redline, idled solid at ~1000rpm, stop-and-go traffic. But just this week had a strange stumbling issue while cruising at 65mph on the commute home. CEL went on, clutch in, and revs wouldn't drop, motor revved erratically...pulled over, saw no vacuum leaks (thought something was wrong with my intake install). Turned it off, then turned it back on, all was well. Made it home. Redid the intake thinking it was a vacuum leak. Test drove for 15 minutes, no problem. Next day, sitting at the freeway onramp, same problem started happening again. Thought it would clear up on its own (it did) so kept driving. Nothing out of the ordinary until 15 minutes later when erratic revving, CEL came on, loss of power with throttle. No strange metal-on-metal motor noises...tried to goose it off the freeway and it died. Cranked but wouldn't restart.
Thinking it was a wiring issue or some weird intake thing, had the car towed home. Double checked everything, all was good. But sitting in car with ignition on, I didn't hear the fuel pump prime...BINGO. Bad fuel pump or relay or wiring...so I pulled the two 4 prong main relays, jumpered each until I heard the fuel pump kick in (so the fuel pump was good). Here's the important parts: I left it jumpered, so the fuel pump kept running for at least 2 minutes. I also left the other relay removed (O2 heater, I believe). Tried to start the car and it ran like shit, sputtering, no power, lots of smoke out the exhuast and a loud intake backfire.
Shut it down and realized my stupidity probably flooded the motor. Pulled the plugs and they smelled like gas. Checked the oil and it didn't smell like gas. Replaced all the plugs with new ones, replaced all 3 relays (fuel pump, main, O2 heater) with new ones, tried to start it and same damned problem (sputtering, no power, smoke out the exhaust, backfire).
Thinking I completely broke the motor, I went to bed.
Pulled all those (new) plugs just now, they all look fine except three of them smelled a little bit of fuel. Motor turned OK by hand. Checked compression with open throttle, and it looks good (phew): 1-180, 2-190, 3-195, 4-195, 5-200, 6-195.
Before I try starting the car again, I'd like to hear your thoughts and suggestions. The rational part of my brain is telling me to throw in the towel and take it to someone with way more experience than I before I completely destroy this nice motor. I'm guessing:
- Injectors locked open? But I'd be seeing tons of fuel in the crankcase (I'm not) and it should reek of gas (it doesn't).
- I didn't rid the motor enough of fuel? (How do you "unflood" the engine?)
- Bad fuel pump?
- Something else completely hosed?
Thanks in advance,
-Ernie
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