Intermittent whiteish smoke at idle. (Those running Port injection chime in)

[papasmurf_m3]

Hey guys,

I dunno where to start so I thought I'd mention to those running port injection.

Happens on pump or E85. More on pump maybe? Idk

I'm trying to diagnose a ghost. It only happens when car is warmed up in traffic or comes to a stop. When I drive off a huge cloud of smoke but, then disappears and doesn't do it at the next light. Wont come back for another who knows when.

I cant get the car to do it on command or certain driving condition so I have not been able to record it. Or show it to anyone. When it does happen i'm at a stop light or something.



Car runs amazing otherwise. No check lights. No issues.

It doesn't smoke under throttle, during a pull, or while driving.

The inside of the tips are pretty dry.

When it does happen, the whiteish smoke lingers out and it's a big cloud. Few revs or when I start driving it instantly clears up and wont come back for awhile.

Ive tried checking/replacing turbos, Changed new charge air cooler.

Next is possibly change out Direct injectors and if it still does it check out the port injectors.

It smells oilyish. At this point im thinking it could be slightly leaking direct or port injectors and the smoke is just ran unburnt fuel traveling through the exhaust and steaming from the heat.

Any ideas?

[papasmurf_m3]

Aaaand nobody has run into this before.

[Motown65]

maybe its blow by?

[Wanted_M]

Try cleaning MAF sensors, does idle/rpm change or sounds different at all when smoking?
Check OCC and how about crankcase vent issues or a vacuum leak?

How about your front O2 sensors? Log STFT and compare to an old log during smoke evolution.
Just throwing ideas at you, good luck bro.

[papasmurf_m3]

Originally Posted by Motown65

maybe its blow by?

No, compression is fine. You would have other supporting symptoms with hurt motor. I've been down that road before. It doesn't end well. This is aint it.

[papasmurf_m3]

Originally Posted by Wanted_M

Try cleaning MAF sensors, does idle/rpm change or sounds different at all when smoking?
Check OCC and how about crankcase vent issues or a vacuum leak?

Just throwing ideas at you, good luck bro.

Never cleaned maf before. I have cleaned and oiled my bmc air filters a few times so i'm sure there has to be some residue on the MAF. Hmm Worth a try.

I just put the OCC recently. I removed the charge pipes and checked in there nothing really to report. I thought it could be sucking in some gunk. It wasn't.. If it did the port injectors should kinda wash that out.

Crankcase vent issue? Not sure how to check that. I think it would throw a code if you had a vacuum leak wouldn't it?

I was thinking today it almost seems like its sucking in something in the tank and it burns weird and smokes then goes away. Or its raw unburnt fuel from one or more of the injectors.

If it's an issue it would be repeatable and or getting worse. It's appears to be the same random intervals. I cant figure out what to do to trigger it lol.

I change the plugs pretty religiously and have not seen anything other than a happy engine.

So I really don't know at this point.

[papasmurf_m3]

Little update for you guys!. It's gone!!

I just checked it 3 times to be sure. I'm pretty happy rn.

Like some had said I was chasing a ghost. I knew it wasn't serious. I just couldn't pinpoint it. I even swapped new factory turbos. Thinking it was maybe a tiny internal leak of some sort. Ya, Don't do that. My stock turbos are literally perfect! No shaft play, no leaks, bone dry, Perfect data logs. Ohh well. Anyone need some good running S55 turbos or literally new ones with 400 miles? I'll sell either for a good price LoL

If you find yourself chasing an issue with your car. I would strongly advise not to start throwing parts at it. I didn't take my own advice and feel dumb about it.

Do a proper diagnosis and then change only what's needed.

A few things to note. I picked up a OCC.

Swapped a leaking stock charge air cooler.

I also poured in a few bottles of liqui moly oil saver why not.

Happy boosting.