V6 TDI: Smoking on Cold Start (2002)

Hello everyone.

This is my first post in this forum.

I've only ever driven S4/RS4 models before, so I'm used to gasoline engines.

I'm having a problem with my A6 V6 TDI.

'It runs roughly during cold starts when the temperature is around -10°C and produces a little smoke.'

Could it be the glow plugs?

When the engine is warm, it runs very well and doesn't produce any smoke.


'There is a fault in the needle lift mechanism, specifically cylinder 2.'

Hello,

Without the NHG (presumably a specific engine component), the injection start is controlled rather than regulated, which, depending on the timing of the toothed belt, could already lead to blue smoke at these low temperatures.

The best way to determine the exact cause of the smoke is often by smell. You can usually distinguish between diesel exhaust (which tends to be bluish) and oil fumes (which tend to be whitish).

Best regards, Rainer.

The turbochargers in the 2.5 V6 TDI engines often fail after only 80,000 km.
The reason is the long afterglow times, which can be up to 2 minutes.
The easiest way to test them is by unplugging the connector and applying a positive voltage to the ground connection.
If it works, it's good. If it doesn't work, it's broken.