heavy smoke on first start

[tony091]

hi there
took it to rs automotive in shoesburyness (southend) , paul there mechanic has been working on the issue for 2 weeks , he has narrowed it down to a sensor that tells the engine management system to flood the pods on first start he has checked everything from turbos to manifolds and everything is perfect mechanically, other than this odd start that bellows smoke out , it gives the computer a sporadic message telling it its -40 degrees outside so tells it to flood all 10 cylinders for an extremely cold start rather than telling it its +17 outside and this will let the injectors just fine mist spray petrol in rather than flood it ,.
lol

[classba]

2 weeks???? WTF

Scanning it with VCDS would had shown the sensor to be faulty?

[Smudger51]

hi there
took it to rs automotive in shoesburyness (southend) , paul there mechanic has been working on the issue for 2 weeks , he has narrowed it down to a sensor that tells the engine management system to flood the pods on first start he has checked everything from turbos to manifolds and everything is perfect mechanically, other than this odd start that bellows smoke out , it gives the computer a sporadic message telling it its -40 degrees outside so tells it to flood all 10 cylinders for an extremely cold start rather than telling it its +17 outside and this will let the injectors just fine mist spray petrol in rather than flood it ,.
lol

t
Can't wait to hear if this cures the issue. This has been driving me nuts for months..................

[Ricky.REP]

The sense error would depend on if the reading is outside of parameter, if there is no fault code then it would appear it wasn't.

I hope it fixes it, certainly makes sense!!

Cheers Ricky

[RS6-T28RPH]

I have had blasts of black smoke on a cold start until its warmed up but it does go away, i know there is a rapid pre-cat warm up routine in the ECU so it runs very rich. I would guess the exhaust tips are pretty fouled up? usually an immediate sign of a car running rich.

We have the same thing on diesels when we remove the DPF and map it out, the amount of soot coming down the exhaust just coats the exhaust tips, have a mk2 leon fr tdi that is de-dpf'd and one of our stage 1 tunes, smokes a bit at full throttle but still walks through the mot emissions and smoke tests.

For what its worth, and i stand to be corrected, black smoke/soot is over fuelling, white is water vapour and blue is vaporised oil,

[vestax32]

My car did this apparently before I bought it from Audi, I'm told it was the valve stem seals, which was then fixed under warranty. Engine out I think, so would have been very costly. Doesn't do it anymore.