Mako

Hey,

What do you mean by oil in the intake how much, did you inspect it?

Actually I took off the throtle body and it was rather dirty on the inner side of the butterfly valve. There was also some oil on it.
I cleaned it and put it back and after around 1k miles i checked it again and there was again a thin layer of oil-dirt on it.

My mechanic friend drives a 745i roguly the same milage. His throttle body was also dirty and a bit oily.
I asked him about the issue and he told me that in some operating conditions, the exhaust and intake valve are both slightly opened.
So intake valve already opens before exhaust valve has fully closed. This causes the dirt and oil in the intake.

blackonblack
Maybe you could take of the throttle body, clean it, drive 1k m and make a picture of the inside part of the butterfly, than i could compare it to mine.

dawid_w

Did you change that sensor? If it is bad that would cause the intake pressure adjuster to go crazy.

Differential pressure sensor 1 13627585278

http://realoem.com/bmw/showparts.do?...77&hg=11&fg=40

Not sure why the price is not listed.

turboawd

the crankcase vapors are rerouted into the intake, so oil mist can come from there also.

cuto

I'm no expert but I had rough idles on my 535i and it was the HPFP to be blamed. Could that be the case?

sy1616

Catalytic converters are covered by a 10yr warranty right....any emissions stuff is.. I also say 02 sensor btw.

dawid_w

I don't think that the warranty covers catalytic converters damaged by oil leak.

I still think that they are OK. First the oil leak problem needs to be resolved.

I would start with the pressure sensor.

z06bigbird

Not sure how oil can get stuck in convertor, as flashpoint of oil is about 1000 degrees lower than operating temp of convertor.

1. If convertor was seriously clogged, you would lose power while driving car. ( Max speed would significantly drop off.)

2. Identify and write down error codes.

3. Have you check Mass air flow sensor (or BMW's equivalent)?

4. Check for cracked vacuum line. Normally a vacuum line will make the miss occur consistently. It could be a vacuum line that is vibrating a small crack in it. (BTW, not very likely, but....)

5. If miss gets worse under load (a/c and accelerating up hills), check coils.

6. Do you see or hear any spark jumping/grounding from ignition at night?

John@Motorcepts

vacuum hoses. ANd yes, we have seen MANY alternators cause that too.

blackonblack

I cleaned the MAF sensor and the throttle body, now the RPM fluctuates a little bit less, but it idles a lot higher. It is currently idling at around 1,200 RPM.

turboawd

the maf sensor must have been dirty..... is sensing the air flow different now.
the engine computer should readjust the idle automaticaly as you run the car.