[torrque]

Hi all,

I am having this occasional puff of smoke, and I mean plenty of white smoke coming out of the exhaust at times. My wife said - as she drove it more lately - that it drops a big fart

Most likely to happen if engine is idling away for long time, in heavy traffic, and it won't happen more than once a day. Sometimes it happens when you start up, then clears in a few seconds.

It never smokes on high load, pushing it or anything like that.

I had the downpipes out (when I changed them ) and turbos looked ok, dry, no sign of oil, and there was very little play in the wastegate.

I am 100% it is oil , no coolant. Coolant level is at max every since I changed the water pump and thermostat.

I have to top off about 1/2 quart in 2000 miles, so oil consumption is not too bad, but what it is, that's where it goes , in the exhaust .

Is it possible for the emission valve in the valve cover to go bad? I changed the pcv valve with a new one, Rob's, but no change.

Many thanks for any input.

[Faredo]

If its at startup then goes away it CAN be valve guides. try down shifting on your deceleration not enough to make the car slow down, but matching the speed and see if you get more smoke. This would lead me to turbo seal/s.
Clean hot side with your downpipes off doesnt always mean the seals are good. Just means the oil burned off before you can see it.

[torrque]

Originally Posted by Faredo

If its at startup then goes away it CAN be valve guides. try down shifting on your deceleration not enough to make the car slow down, but matching the speed and see if you get more smoke. This would lead me to turbo seal/s.
Clean hot side with your downpipes off doesnt always mean the seals are good. Just means the oil burned off before you can see it.

That's the thing; it's not at startup. It most often is after running the engine idle for a while.

No smoke on deceleration, and no smoke on accelerating hard. Compression is a pretty even 160-162 across all pistons...

I have to add I have no secondary cats, but it still seems excessive when it happens.
I will try to get a new Valve Cover and gasket, it's never been replaced and I see some oil leaks on the side...
That, with the new PCV valve should rule out any crank ventilation issues.

From there on, it can only be turbos.

Thanks

[JM98]

Mine has been doing this for 2+ years since I went FBO (also have RB PCV) and catless mids. I have had nothing but clean logs and the car runs great with no visible leaks, so i don't worry too much about it. I just chalk it up to typical N54 ownership.

[torrque]

Originally Posted by JM98

Mine has been doing this for 2+ years since I went FBO (also have RB PCV) and catless mids. I have had nothing but clean logs and the car runs great with no visible leaks, so i don't worry too much about it. I just chalk it up to typical N54 ownership.

Have you ever changed your valve cover ?

Thank you.

I've experienced a similar issue ONLY when running the MHD wastegate rattle fix. I would get puffs of smoke in traffic, only during/after coming to a stop when easy cruising, etc. Otherwise the car has zero issues and only burns 1 qt of oil every 10K miles.

Only reason why I tried the WG rattle fix to begin with was to see if the exhaust was any louder with the fix enabled. My WGs are naturally rattle free and the only time they rattled was when the fix was enabled lol

More info: VC has about ~40k miles on it. The PCV system is well maintained and I run both high side and low side catch cans. Both WGs were properly adjusted when adding DPs ~20K miles ago.

There was a thread over on the other forum that explained a reasonable theory as to why this phenomena may occur...perfectly plausible IMO, especially given my circumstances, use case, and subsequent results:

Probably turbo(s). As it gets worse coming to a stop and if vacuum unplugged it is probably turbo seals that seal when under load but not at idle/low load. At least that is my theory for my turbo(s). Making sure to have idle/low load WG duty cycle set high (opposite of "WG rattle fix") reduced/cleared my smoking issues, but they were not too bad. Best fix was turbo upgrade though. =P

[torrque]

In my case it happened before it was tuned, and to lesser extent before I removed my secondary cats. After secondary cats removal, it seems excessive now Which is normal in a way...

Well, yeah, that's not surprising at all.

[JM98]

Originally Posted by torrque

Have you ever changed your valve cover ?

Thank you.

Haven't seen a need to, no leaks anywhere I can see including down inside when I swapped spark plugs, coils, and injectors.

[Bimmer_Engineer]

Originally Posted by JM98

Haven't seen a need to, no leaks anywhere I can see including down inside when I swapped spark plugs, coils, and injectors.

How much oil do you burn between changes?