Engine salls

[BimmerKris]

I can't figure this out, when it gets hot out my car will randomly stall. I have to wait a few minutes for it to start up again. But it only runs for a few minutes after that. When it is cooler outside it has no problems. Now it also has a buggy, chugging feeling at lower RPM's, this has been goin on for a while and i think they are related. So far i've changed, the o2 sensor, spark plugs, coil, air filter, and have tested both fuel pumps and the pressure regulator. I'm all out of idea's, if anyone else has the a possible solution, please let me know. thanks

[BMWJNKY]

How did you test the fuel pumps? Did you look at the amp pattern with a scope of some sort? Have you tried changing the Motronic and fuel pump relays?

[MrM3]

check for vacuum leaks. take a good look at the intake boot, especially in the creases, for cracks or holes

[gotKRAUT]

My info here is worthless...just thought i would say when it was hot outside my 325e would have major powerloss in midrange...the motor wouldnt be running hot, just if it was hot outside...on a nice cool night she was smooth all the way through the powerband...never could figure it out...checked the vaccum lines and intake boot, and all that good schtuff..i finally just gave up and figured it was because of efficiency..it was sucking in more hot air..matter of physics...cold air is more efficient..but i was probably just lazy and there really was something wrong

[BimmerKris]

Originally posted by AJ's320i@Jul 18 2004, 11:49 PM
How did you test the fuel pumps? Did you look at the amp pattern with a scope of some sort? Have you tried changing the Motronic and fuel pump relays?

i had to by pass the relay and send power right to both pumps. I read in a manual that they should pump a minimum of 875ml in 30 seconds. and that worked fine. I have checked ever vaccuum line the whole air intake system. Could it be the fuel pump getting to hot and shutting down. After i let it sit for a bit, it will start again, but to try right after it stalls, it starts like it is out of gas. Or could the ECU be getting hot a shutting something down, in not fimiar in those areas, so im not sure. I'm also thinking it might have something to do with the chip i installed, could these be possilbe?

[MrM3]

have you tried putting the stock chip back in to see if the problem goes away?

[BimmerKris]

i have thought of that, what i can't think, of is where i put the damn thing

[Shiftygunn]

I had a similar problem with my 85 325e, I have done extensive research on the matter. There is a guy named Sam at www.mesaperformance.com/faqs/idle.html who knows a lot about BMW idle problems. I would say that your Idle air control valve is probably sticking because of the air temperature or relative humidity. An electric fuel pump typicly just dies. Although apparently some can be lightly banged with a hammer, but that still wouldn't explain inconsistent behavior. Anyway I would read his faq. I replaced my ICV and it works fine now. But the best method for solving mechanical problems isn't to just start replacing parts. Any way good luck.