E30 M40 stall when AC is on

[Alejandro]

Hi guys,I've got a manual 1990 E30 with M40 engine. Recently the engine stalled in the fast lane on federal highway when in gear (braking due to traffic jam ahead with clutch fully depressed while the RPM drop below 1K). I've to stop the car at the road side and restarted the engine without any problem. This happens ONLY when the air conditioner switched ON (does not happen when I'm driving with the AC off). And this too does not happen when I free the gear.Does anyone knows what had happened? Is this a common E30 problem? Need advise.Thanks!

 

[pussy]

very common in almost all bmw's....

need a good clean up with the trottle body, icv, icv rubber O ring, sticky AFM flap...

 

[JFT63]

Yup, same issue as my e34 m20..cleaned ICV and sorted the issue.

 

[Aero]

Would say is normal then, as i have this headache some time ago, took me some time and plenty of frustration to sort it out, i have done all of the above, and the final result to my problem is to tweek the AFM and also the trottle body adjustment.

Now so far so good........

 

[Alejandro]

Thanks all for the feedbacks. For a noob like me, I don't think I can DIY this. Could provide me a rough estimate on how much does it costs? e.g. If I send it for servicing and retuning? The car idles good, I only have this problem.

Thanks.

 

[yat325]

hope ur prob can be solve bro..

 

[Aero]

Last experience, they cannot solve but to only change the AFM they hope to solve it, which did not,it is the same,so i revert to my original one that came with the car, and i tweek it my self, if known earlier, i would have save the money and the trouble.

Cheers

 

[Alejandro]

How did you tweaked it?

 

[BobTheBuilder]

I'm also having similar problem with my E30 since 2 days ago. But the slight difference is that the engine only stalled/died when i go over very bumpy surface.

Reading at the feedback here, I think i have an idea now of what the issue might be.

Thanx guys.

 

[Alejandro]

Just to update. I've opened the AFM and blow some air on it. Re-seal it and so far so good. RPM does not drop too much as what occurred previously when AC is running and when coming to a stop. It idles nicely at 800 RPM even when AC on. 15 minutes job.

 

[BobTheBuilder]

Glad you found the solution bro.

Mine not so lucky. My fuel pump relay was the culprit.

 

[johnvk]

bob.. how much did it cost for the fuel pump.. i better prepare for that one...

 

[BobTheBuilder]

bob.. how much did it cost for the fuel pump.. i better prepare for that one...

I paid about RM200 for it, but didn't last long.
Returned it and order from Germany instead. This one about RM500.
I'm not sure if our Fuel Pump Relay are same though.... (M20 vs M40)...

 

[zlurp]

I'm having a similar problem, when I turn on the aircon the revs jump up and down, and once in a while the revs will drop too low and the engine will stall. The joke is when I'm at the garage it wont happen....

But temp fix I've found is to rev the engine when I turn on the aircon, seems to work for now, but I'm going to try cleaning the ICV.
http://forums.bimmerforums.com/forum/showthread.php?t=454501 Here's a guide if anyone wants to try.

 

[ICEMAN 68]

sir jarance has got a good diy topic on how to clean these AFM thinggy ...do a search here ....not mistaken an old thread back in 2006~2008