I have recently purchased a 53 plate a3 with the 1.6 bgu petrol engine that has a smoke issue along with oil sensor warning.
At first start up it would misfire badly but once warm sorted itself out. Also noticed the temp guage would take a while to register and then it would only stay at 50. Changed the temp sensor and thermostat, seems to have sorted the initial misfire issue along with temp guage which now stays at 90 once warm.
Diagnostic was showing misfires on two cylinders, changed the one spark plug, it was covered in oil and changing it cured the misfire on the cylinder.
Now to the smoke, at start up there will a puff of grey/black smoke then nothing . At tick over there is no smoke, when reving the engine there is no smoke. It is only when you release the accelerator that there is a big plume of smoke. There is a oil on the ground from blowing out the exhaust.
There is no loss of power I can tell. The previous owner changed the oil 800 miles ago and since then the problem has surfaced, he parked it up at a garage soon after not wishing to spend any more money. I purchased it from the garage.
Any suggestions of possible causes?
The oil sensor warning is on the dash in yellow, did the trick of disconnecting the battery and touching the terminals. This removes the light but will appear on next start up. Diag shows a short? Any problem areas?