[accidental_mechanic]

Hello all,
I've been poring over these forums the last several weeks and I've read many threads about smoking issues, in their entirety, and I realize there are several common reasons that they can do so. However, I've yet to read about one which matches my symptoms precisely, and I thought I would finally reach out and see if somebody can help.

The car:
2008 335i / 148k mileage
Stock other than following:
Catless dp
Index 12 injectors
Replaced the PCM with an RB upgraded one
Replaced the flapper valve hose
Installed an oil catch can
BM cone air filters

Recently bought it, so it's hard to tell what's all been done.
No visible leaking from valve cover (gasket could have been replaced?)
No idea of whether it's ever had walnut blasting or not
Runs well, only noticed a momentary misfire about twice in the last 350 miles
No engine codes at all other than complaining about the cats (or lack of)
Pulls strong, but I don't have anything to compare to...

Spark plugs look normal. (to me) Not particularly black or dirty.

Symptoms:
At cold start, no smoking whatsoever.

After driving about 5-10 minutes and stopping at a stoplight or stop sign, the car will sometimes begin pouring out smoke (light blue/gray) from the tailpipes. Not every day, but often. During my work commute (30 minutes), it will smoke in varying degrees at stoplights. So, I have this all-the-time (moderate) smoking after the engine is warmed up, with occasional dumping of lots of smoke at idle.

As far as I can tell, it does not smoke at higher RPMs, only lower and idle.

The smoke does not smell sweet. At all. It's never black. Both of which convinces me it's not likely to be coolant or injectors. (I have index 12)

Setting overnight does not produce an initial smoke burst on startup, making me doubtful it's the valve stem seals.? (still a possibility tho?)

Here's a video of it smoking badly...

View post on imgur.com

I pulled the downpipes off and here's the pics of what I'm seeing.

Bank1


Bank2


I had hoped to be able to see lots of oily gunk in here, but when I parked the car to take off the downpipes, it wasn't smoking all that badly. So, I suppose if it's not dumping oil out of the seal/bushing, it's getting burned up almost instantly (no oily residue). I don't know what the gray/brown/white residue indicates, if anything. Do these look normal for a healthy turbo?

BTW, I can get a tiny bit of forward/aft play when I grab the impeller and push/pull. I suppose even a tiny bit of play that way is bad...

My goal of this post is to get help verifying whether the turbos are indeed the culprit. I suspect the turbos, but if my symptoms match that of failed valve stem seals, I'd like to know that as well.
TIA

[MADDX6TT09]

Well i dont believe your flappers are supposed to be open. cant see where its sealing against the seat. White and ashy means its hot or lean... how are your fuel trim numbers? Short term and Long term?

[MADDX6TT09]

My mistake 06 prior wastegates were closed naturally...

[Brandoch]

Originally Posted by MADDX6TT09

My mistake 06 prior wastegates were closed naturally...

MY 2007 was the first year for the N54...........

[accidental_mechanic]

Originally Posted by MADDX6TT09

Well i dont believe your flappers are supposed to be open. cant see where its sealing against the seat. White and ashy means its hot or lean... how are your fuel trim numbers? Short term and Long term?

Both of my Long Term fuel trims average around 12-14% and my Short Term hover around -3% - 0%. That's the last numbers I pulled when idling after warmed up.

[David_avina]

Did you ever find the issue? I’m having similar issues right now