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-   -   e36 m3 idle, deceleration problems (http://forum.e46fanatics.com/showthread.php?t=952355)

STORMER 10-24-2012 11:37 PM

e36 m3 idle, deceleration problems
I am trying to address an issue over on bimmerforums but am too new to link videos so I am going to post them here! :thumbsup:

If anyone here can help please chime in!

My car is a 98 m3 with an Active Autowerkes Stg 2 kit.
10 lbs boost
m50 intake
underdrive pulley from 90,000 up to 98,000 rpm
supersprint exhaust
cat delete
m5 clutch
lightweight flywheel




Video 1 shows how car "hunts" for idle when warm and sometimes find it and sometimes stalls.


Video 2 show how the car is completely fine and runs great when cold.


Anyways the car has a real hard time "finding" idle when its warm, to the point it will sometimes stall out.

Also bucks when decelerating in gear, which also seems to be isolated to when its warm.

Its a new car to me, but obviously not new to bmw's but new also to fi.

Thought maybe icv but then why only when its warm? Maybe tune?

Also noticing a bit of oil looks sprayed under the intake area. Like its down in the area around the power steering resevoir and ontop on the control arm etc. Not sure if related but where is it coming from? Oil level is fine and all fluid levels seem ok.

Also vcg needs to be replaced, is it possible its getting oil into area described?

All I can think of at the moment. thank in advance

braymond141 10-25-2012 12:06 AM

I think you need to go through and check anything that is crucial to holding vacuum/boost. Your issue looks like a vac leak.

(I have 10psi going through my 96 M3 for reference).

STORMER 10-25-2012 12:07 AM

So just get a smoke test done to start I guess eh. You think its related to the bucking issue?

braymond141 10-25-2012 02:16 AM

Yes absolutely. A failed or dirty MAF can be a cause too.

I'm unsure if that kit requires resistors for the MAF. PM Marco on bimmerfourms, he sells those kits and will know.

STORMER 10-25-2012 01:31 PM

I have booked the car for a new vcg and a smoke test on Nov 12. Earliest I could get in. Will keep updated.

As for now is there any other ideas?

Can a charger itself develope a leak and if so can it be fixed with new seals? I would assume so no?

A4RingedONE8T 10-25-2012 01:47 PM

Oil under the intake area, as in near the headlight, or under the intake manifold? Most likely is a vac leak, lots of plastic stuff to age underneath the intake manifold. Smoke test will most definitely show your issues if there is one. Reason it runs fine cold and not when hot. Cold = open loop/fixed map. Hot = closed loop/sweeping a/f. This is the reason it proves most likely to be a vac leak. On fixed map, aka ignoring sensor inputs it runs fine. As soon as it goes into closed loop and starts relying off 02 sensors and others it stalls out

STORMER 10-25-2012 02:34 PM

Ahhhh ok this sounds like it makes more sense. This is the answer I was looking for. I appreciate it. :thumbsup:

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