smoke on start up

[Chrispy]

i have a 1994 vr berlina v6 and it blows a puff of black smoke on start up, no smoke or anything when its running.

i can have the car running, turn it off then turn it straight back on and it will blow smoke.

Any ideas? stem seals?

[Brett_jjj]

A leaking fuel injector or fuel pressure regulator.

[cander24]

Agree with Brett_jjj above. My guess is a leaking injector. Basically this means that one (or more) is not closing fully and is continuing to leak fuel into the cylinder even when there is no electrical pulse to it. This excess fuel already there causes it to run rich on start up, hence the black smoke.
If it were stem seals it would be oil that it's burning and would be more of a blue smoke and wouldn't do it only on start up. Exhaust would smell distinctively different to being rich too.

[hako]

To track the leaky injector down, just screw the plugs out and look for the wet one.

[Chrispy]

To track the leaky injector down, just screw the plugs out and look for the wet one.

Spark plugs? might take the fuel rail off and suss it out just to be sure. After I turn the car off I can hear a kind of priming sound coming from one of the hoses near the master brake cylinder, I think it is the fuel line.

Sometimes the smoke is a little white and black.