My 1996 A4 B5 1.8 T has done only 30,000 miles, but uses quite a lot of oil, and the spark plugs always have oily carbon deposits on them. It is also slow to start, taking 2 or 3 seconds cranking before it fires, whether the engine is hot or cold.

The oil consumption has been about 1 litre per 2,000 miles since I bought the car early last year, with 25,000 miles on the clock.

Re. Slow starting.

In case this is due to a faulty engine temperature sensor causing a rich starting mixture, I checked indicated coolant temperature with my VAG 1552. It shows the temperature as ambient before starting, and gradually rises in a normal way.
I recently replaced the thermostat, and the temp. gauge shows 90º when driving.

I put in new spark plugs, but this made no difference.

In case the N80 valve is faulty, causing the EVAP canister to discharge into the inlet during starting, causing a rich mixture, I blocked the hose from the N80 valve to the air inlet, but this made no difference during several starts.

Re. Oil on plugs/consumption

As mentioned in previous posts, I removed and checked the PCV valve for the crankcase. It is working properly, and there is no positive crankcase pressure evident when I remove the oil filler cap at idle.

Today I measured compression pressures with the engine hot, all plugs removed and HT coils and injectors disconnected, expecting possible low values to indicate excessive blowby, but values are way above minimum.
Specs are: Minimum pressure – 7 Bar, maximum variation 3 Bar.

Results: Cyl’s 1 to 4: 13.3, 13.8, 13.8, 13.9 Bar.

All the above seems to indicate that the engine is OK, so is it likely that the plug oiling and oil consumption is due to a failed turbo oil seal?