Desperate to figure out this smoke issue.

[Mk5_mikey]

Hello all, new to posting on forum however I've been lurking for some time now.

I'll keep this short. I've tried searching for answers throughout the forum but it has been to no avail. My car has 131k on it and for the last 30k miles or so has been doing something very odd. From time to time it's POURS gray smoke that carries an odd odor. It only happens under gradual throttle up around 3500-4000 rpms. But here is the kicker, it doesn't happen each time. I leave the house, drive casually, then decide to be a little spirited with my driving and then it happens. I mean smoke like you wouldn't believe. Then as its happening I expereince an odd spitting noise and power loss clips that are in sync with the spitting noise. I let off of the throttle immediately, the exhaust pops a few times, then I apply throttle again, and it spools up again like nothing happened. After a few hours of going about my day, it might happen again once or twice.

Now most of you will say my turbo is blown. It's not. I just replaced the turbo with a brand new one 1k miles ago. I've replaced sparks plugs, coil packs, even replaced the valve cover gasket in hopes that this issue would stop. It hasn't. VW claims it could be an injector. Maybe? I'm not sure. That's why I'm here. Surely someone has had the same issue and can help out. It's completely embarrassing when the cars behind me have to damn near stop until the smoke clears. I'll include my mod list below.

APR flash.
K&N typhoon intake.
Rev D DV with DV+
3 inch catless DP with a Magnaflow resonator.
Noise Pipe Delete

Now for the parts I have replaced trying to fix this issue.

Multiple cam followers
Cam shaft positioning sensor
New HPFP and cam shaft (under warranty)
New turbo and hardware
Valve cover gasket
New purge valve
Coil packs and plugs
PCV (done under warranty)

If anyone has ANY ideas, I'm all ears. This has to stop.

Thanks guys.

 

[af09808]

Blow by threw the piston rings and might have a stuck ring

 

[Mk5_mikey]

Blow by threw the piston rings and might have a stuck ring

If that is case, how do I go about fixing the blow by? Catch can?

 

[af09808]

Try that but I know the only real way is to re ring the Pistons which I'm in the process of doing but in my case my valves crunched my Pistons so I got all new stuff

 

[firas1981]

look. i had this nightmare before you. and i did all what you did and nothing changed. based on my experience with that exact issue, first you need to check your fuel pump, if its brand new as you said then its not an option. second check your injectors. you simply might have a stuck injector. remove your intake and remove them all and do injector pressure test. it should give you the result whether they are all good or not.

if that is all done and still the problem is not solved, then you do what i did, i took it to a mechanic in lebanon ( where i live not usa ). and he took my engine apart, bought a new set of rings and he machined the lower block and used some sort of thicker rings. apparently all audi q5 and q7 has this issue recently and the cure was installing thicker in size ring. you need to ask a professional to do it or give you better explanation i guess./
but this solved my problem like a dream., and the great part is that its not eating oilllll any more. i barely use 500 ml every 6000 miles.

hope i was helpful and excuse my language if any mistakes done.

 

[zrickety]

If it's not an injector, you can be sure it's internal. Probably need to do valve stem seals, deglaze the cylinder walls, new rings and gaskets at a minimum. Basically a rebuild, then do 5k oil changes to prevent these issues.

 

[ROH ECHT]

Been there...done that :frown:

Mine smoked under heavy throttle, when coasting to a stop in a low gear, and when taking off from those stops. I did the EVAP reroute and the valve cover replacement that has fixed this for some. Even though I found my valve cover to be damaged...the replacement didn't solve this. So I had to go forward with a rebuilding of the head, which is mostly inexpensive, and found that my valve stem guides and seals were shot. While the head was taken off for its rebuilding...two of my cylinders on the cylinder head were soaked in oil, 3 & 4(see pic below), we removed the #4 piston and found the piston groove was crushed onto its piston rings. I had to then replace that piston and all the piston rings.

You can try checking and/or replacing things that have been mentioned. If these fail to correct the issue...try the valve cover. Then you are likely going to need to remove the head. Have the valve guide-to-stem clearance checked and replace the guides and seals if found necessary. When you remove the head...look for this:

...if you see oil like that on the head ↑ ...you need rings :thumbsup:

You can find a vid on my youtube channel explaining what to look for with regards to the valve cover @ Roh Echt on youtube.