Please assist a new E30 owner

[ppc]

Dear Listers:

Greetings! I am a newcomer to the E30 family. Please be so kind to diagnose for me the curious behaviour of my newly acquired 1989 318i:

1. She stalls occasionally without warning, usually when coming toward a stop (yet before a complete stop). Restart the car then she is fine again.

2. Occasionally, She would lose torque dramatically when attempting a steep slope, even in first gear. The engine is still smooth without extra vibration, yet it simply would not output power, as if not enough fuel is obtained.

3. Idle speed sometimes drops and stays around 600 rpm, and the engine consiquently vibrates dramatically.

Now, all of the above mentioned curious behavious happen "occasionally," and seem to have a relation to fuel tank capacity. When the tank is full, she acts rather normal. When the tank drops below half, she starts to do these notorius things.

Oh, last but not least, I think the cylinders' output are imbalanced.

Any comments? I have had, and still own other older classics, but this beautiful E30 is the most curious one. I thank you all in advance.

paul chiang, Taipei

[Sanchez]

could be the fuel pump or the fuel regulator.

[tomtomiS]

sounds like its pressure related

[johnono]

icv mabey

[jcjdavis1]

Welcome to the zone

[BochumBass]

I've been having similar issues for a while, except mines the other way round, the more petrol there is the worse it runs. Once the warning light comes on it runs pretty well but anything over that and it's a nightmare.

Most things have been checked, the fuel pump is making a racket so that's getting changed for a new one on Monday, if it cures the problem I'll let you know as your symptoms seem almost identical to mine.

[ppc]

Dear Sanchez, Tomtomis, Johnono, jcjdavis 1, BochumBass:

Thank you all! None of you think this could be related to the AFM? Or perhaps also related to it?
For BochumBass: I look forward to your relief on Monday!
For Johnono: Which part of ICV? itself, wiring, vacuum? Also I've heard that it's very hard to find a good replacement ICV unit, even a "new" one from Bosch could be faulty... Is this true?
For Tomtomis: Which part might be having pressure problem do you think? Fuel line, or cylinders, or vacuum, or something else?

I thank you all again!

[johnono]

afm may well be the culprit fella if you can find a replacement or just a swap for a couple of hundred miles just to see if it makes a difference.

i would say the ICV is more of an expence issue than an availability one. i think they cost in the regions of £150 new and mabey £30 used

u could easily find one herte , reconditioned and sent to you for less than that ;)

the icv is an idle control valve


Bochumbass

yours sounds like an injector problem, see about an ultrasonic cleaning