e34 unstable on idle
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Guys, I got this problem on my 91 e34 m50, when it's idle with the clucth pressed down the engine runs very unstable, tachomether pointer starts twitching and apparently engine stops. After that I can start that immediately, but the problem is still present.
I lurked a bit and think it may be "crankshaft position sensor" that is problematic, but not sure.
Maybe any ideas on this issue? Thanks inb4
>>14626438
>crankshaft position sensor
Once that thing fails, the car will not turn over
What you probably have is a vacuum leak, dirty throttle body, or faulty throttle body..
>>14626438
Only when the clutch is in? Not when it's in neutral with the clutch pedal untouched? I'm guessing a vacuum leak to the clutch cylinder assuming it's power assisted.
>>14626771
No, it's both in neutral and with pressed clutch.
>>14626709
I heard something about if you have siemens computer the car will be able to operate even with failed crankshaft sensor due to the camshaft sensor. Don't know if it is any true, though.
I actually had an accident about a week ago when engine just stopped and wouldn't start (starter worked, but no spark presumably), after waiting for half an hour it started ok.
>>14626850
>>14626771
fugg I mean it happens both in neutral with clutch unpressed and geared with clutch pressed
>>14626850
>>14626854
Check the boot on your intake manifold. If there are no tears/leaks (you can check with brake cleaner, spray it around at idle and listen for idle to raise), check the fuel pressure on the fuel rail. Look up proper specs for it. It could be a bad fuel pressure regulator, judging by how the car started up again after 30 minutes. I would replace the crankshaft position sensor just because they tend to have a very finite life and I assume you don't know when it was changed. I'm not sure how the Siemens computer affects things.
>>14626438
idle air control valve?
>>14626916
That's a good suggestion too. OP, open the throttle just a bit, does the problem go away?
>>14626438
How unstable? How many revs does it bounce between?
>>14626916
>>14626928
If you ask if I can solve the problem with constantly pressing on throttle, then asnwer is yes, I can do that. Very tiring to press all three pedals in a slow traffic jam, though.
>>14626912
I will look into it, thanks.
Actually managed to make a small recording of the problem. In the video I don't touch throttle at all, the engine doesn't stop yet is very unstable. Later that day and generally in a more heavy traffic it gets worse and if you hold clutch even for a couple of seconds, the engine stops.
https://www.youtube.com/watch?v=GzI9QzlOyq4
Here is the video, been trying to figure out webm stuff but failed
>>14627106
>slow traffic jam
Why the fuck did you buy this car
>>14627195
it's not like I intend to bomb traffic on it every day
>>14626438
What a surprise, a BMW with an electrical issue.
Things in order of what I think it could be:
Vacuum leak
Dirty/faulty MAF Sensor
Dirty/faulty throttle body
IAC
There are various ways to test for these on your own.
Personally I'd disconnect the battery and pull both the MAF and throttle body off and clean them (no touching anything, just spray them with MAF cleaner because it's extremely volatile, leaves no residue which is critical), reconnect the battery, fire her up and let the idle work itself out over 5 minutes. People should do this every 25,000 miles anyway as routine maintenance so it's a good starting point.
If that doesn't cause it to be stable start checking for vacuum leaks.
>>14626438
It is not crankshaft sensor. If it be the engine will increase rpm very slow and under 2-3k until you reset the computer.
I think the problem is in the fuel system.
>>14626438
Running on 5 cylinders maybe? Check the spark plugs.
>>14627333
>>14627560
>>14627578
Thanks a lot guys, I will check that
