Where are my E30 M10 gurus? My new-to-me 84 318i was described as having a likely ICV and or vacuum leak problem. Seller said it would start but not hold idle. I've been messing with it a bit today and found that it will start, but it's almost impossible to keep it running unless you keep the throttle about 1/2 way down, then it stays running, horribly, like it's on 3 cylinders. You cannot bring the revs up at all. When the car first starts, I can hear the cold start valve spraying and the car revs up fairly smoothly for just a second (burning off that shot of fuel is my guess).
I have not found any massive vac leaks, I tried blocking off the ICV completely to see if there was any difference (there was none). The car seems to have been fairly well maintained, PO was a doctor who was not afraid to fix things when they broke. I tried unplugging the O2 sensor, makes no difference.
Here's the strange thing. When I unplug the AFM, the car runs WAY better than without it plugged in. Not saying it runs well, but I can easily rev the engine, and as long as I keep the revs up, it runs OK. Car will not idle at all, but it doesn't idle at all with it plugged in either. I can't understand how the car can run like this with the AFM unplugged, it makes no sense at all, especially the part where it will freely and smoothly rev when I press the gas. I would expect it to maybe start and run, but not rev when I push on the gas (since there's no signal from the AFM telling the ECU that the flapper is opening more).
Any ideas would be appreciated. Keep in mind that I am far from a newb when it comes to E30's (or many BMW's for that matter), and the above are just my observations from a preliminary look at the car. Based on what I've seen, I feel pretty sure that the fuel pump (pressure) is OK, the timing is generally OK, injectors are all working OK, plugs/wires/cap/rotor are all OK. The issue is with the fuel/air mix and/or fuel delivery, but I'm not sure what's going on.
I have not found any massive vac leaks, I tried blocking off the ICV completely to see if there was any difference (there was none). The car seems to have been fairly well maintained, PO was a doctor who was not afraid to fix things when they broke. I tried unplugging the O2 sensor, makes no difference.
Here's the strange thing. When I unplug the AFM, the car runs WAY better than without it plugged in. Not saying it runs well, but I can easily rev the engine, and as long as I keep the revs up, it runs OK. Car will not idle at all, but it doesn't idle at all with it plugged in either. I can't understand how the car can run like this with the AFM unplugged, it makes no sense at all, especially the part where it will freely and smoothly rev when I press the gas. I would expect it to maybe start and run, but not rev when I push on the gas (since there's no signal from the AFM telling the ECU that the flapper is opening more).
Any ideas would be appreciated. Keep in mind that I am far from a newb when it comes to E30's (or many BMW's for that matter), and the above are just my observations from a preliminary look at the car. Based on what I've seen, I feel pretty sure that the fuel pump (pressure) is OK, the timing is generally OK, injectors are all working OK, plugs/wires/cap/rotor are all OK. The issue is with the fuel/air mix and/or fuel delivery, but I'm not sure what's going on.
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