Smoke Cloud Panic

[gonzoninja]

Today, while having a um \'spirited\' drive along the A3 I noticed a massive plume of bluish smoke come out of the exhaust when lifting off from full boost.

My first thought was the engine had let go, but there was no change in engine noise and performance still seemed to be there.

So my second thought is that is was oil in the turbo, however oil pressure seemed to be okay (but this is the FD gauge, so who knows) and oil temp was holding where it had been (my guess being that if oil it pouring into the turbo less oil would be cirulating and oil temps would rise).

Having said that I am running a bit of premix at the moment, but I would have though if that was the cause of the smoke then it would be constant all the time.

Anyway I drove it a bit more carefully on the way back, when driving normally there was no smoke. I did boost it to see if the smoke appeared againg and it only happened when I lifted off the throttle and coming off boost.

The car runs a Carl Hayward map and I think it is quite rich (not that I have a problem with that, better to be rich rather than lean), so could it be something to do with the the wastegate closing and forcing more through the turbo, hence the cloud?

[PDale]

Have you only just started using premix and what ratio to fuel are you using?

Blue smoke is burning oil. If its only started doing it since you have been premixing and only when you lift off the throttle after WOT then I would say its the premix.

Reasons being, premix is designed to burn relatively cleanly compared to engine oil so under light throttle driving it shouldn\'t produce any noticeable smoke. If you have a slightly rich map you sometimes get the fuel igniting in the hot exhaust (pop and spit) after you lift off from full throttle as the engine hasn\'t had chance to burn all of the fuel due to the injectors dumping a load of fuel in. If you factor in the unburnt premix mixed with the unburnt fuel, the premix won\'t have had chance to burn cleanly and will result in smoky emissions.

[bumpstart]

crankcase breather system is not coping ,, maybe purge solenoid or PCV valve issue, or modded system
if you are single turbo know you may need to mod the system for a catch can with a drain down to the disused turbo drain

[gonzoninja]

I\'ve only recently started using premix, so that could be why I\'ve not noticed it before.

There is no cloud of smoke on start up, which I guess you would expect from an oil leak or a turbo oil seal going.

Yes it is single, and it doesn\'t have a catch can, so may that is something I need to get.

thanks for the replies. At least it doesn\'t seem to be anything terminal

[Ricco_04]

If its when you lift off then doesnt that point to turbo oil seals?

[PDale]

Might be worth using up the remaining fuel in your tank and putting in just fuel with no premix just to see if it makes any difference and possibly rule it out. Obviously only do this if you still have a functioning oil metering pump.

[gonzoninja]

I have no idea if you lift off then that is when the oil seals leak. Why would that be? I have no idea, so that\'s why I\'m asking the question.

According to my PFC the OMP is working intermitently, it seems fine on a run but not when idling hence why I\'ve started pre-mixing

[gonzoninja]

Took it for a quick blast this weekend and it didn\'t seem to be doing it. Although the OMP didn\'t seem to be working very well (hence pre-mixing), last time it seemed to be working well

so what I\'m thinking now is that with the pre-mix and the normal oil from the OMP it was probably not burning properly and thus coming out of the exhaust.

There is no smoke cloud on idle, which I\'m thinking is the oil seals leak when there is negative pressure (i.e. not on boost) then you\'d see and smell something then.