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E39 M54 stalling and powerloss issues

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I'm new to this forum but not new to DIY german car world. I'm having an issue with my 2002 530i and I'm searching advices from the E39 community.

-engine off and warm
-started the car and put to reverse for backing up a parking lot
-engaging in drive and depressing the accelerator caused the engine to stall
-started it again - same issue
-started it again, put to drive and drove on idle without touching the accelerator. Stopped the car, put in neutral and reved the engine for 2-3 min - no issue this time.
-no warning lights in the instrument panel - I haven't check for OBD2 codes yet.

I tried to replicate the problem at home in the driveway - can't replicate. Drove the car in the street with applying some brake pressure to put some load on the engine and the RPM cyclically drop by roughgly 1000 RPM and goes back up to normal on a warm engine.

No bad sensor or vaccum connections found during a visual inspection.

Any idea on the origin of this issue?



2002 BMW 530i
1989 Porsche 928 S4
1 - 12 of 12 Posts
Unplug MAF and see if it happens again.
Ok...I'll post results today...


...engine is warm, unplugged the MAF...engine RPM immedialty drops to idle with very little load (little brake applied when driving). Worse when compared to a plugged MAF.
Stop stumbling around in the dark, and get the codes scanned....that`s the only way to get to the root of the problem.
Getting the codes is certainly the right answer. Stalling can be from several sources ranging from input leaks, bad CCV, bad MAF, weak fuel pump, clogged fuel filter, bad ICV (if present), bad O2 sensors, and others, and hence the need to get the codes. If you KNOW the service history, that will help, but the real answer, as indicated earlier, is to get the codes.

2001 540iA Sport
I agree for the code. A reader's on the way this afternoon. Will I get something out of it even if no check engine light is showing?

I'll post the result later on...
Just checked the OBD2. No code logged in the computer.

Any thoughts on what to look for?
What reader did you use to check for DTCs? Generic readers usually provide only a minimum set of mandated emissions related codes and most of those from the engine only.

It's possible that other components, e.g. transmission, are involved in the symptoms you describe. Further many DTCs are unique &/or readable only by BMW compatible software. Those sorts of DTCs may be needed to get to the root cause.
Just checked the OBD2. No code logged in the computer.

Any thoughts on what to look for?
Don`t know what type of "reader" you used, but it`s *virtually impossible* to have any type of mechanical/electrical/fuel problems present, and not leave any codes behind....
Just checked the OBD2. No code logged in the computer.

Any thoughts on what to look for?
Do a search for, Vacuum leaks revisited,--start on all the listings I made--vac leaks will cause the problems your having and until the leaks get big enough there won't be a code to let you know what your problems are.
On my way for a vaccum leak quest...I'll keep you posted...thanks...

1 - 12 of 12 Posts
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