Thankyou very much for your help, well check the belt and timing
first.Cheers, Alan.

Black Smoke is mostly unburnt fuel and/or poor timing.
_DARK_ grey smoke is usually contaminated fuel or a very small amount
of burning oil mixing with contaminated fuel. When is the last time you
drained the water out of your fuel filter?
_LIGHT_ grey smoke is usually burning oil to a serious degree. If you
are burning a very large amount of oil, the smoke will be a dense,
white, stinky mess.
Smoking when accelerating could be bad timing as well.
_White_ sweet-smelling 'smoke' is usually burning coolant.

Suggestions:

a) make sure that the timing belt is good and within its service
interval, and that it has not skipped a notch.
b) change your fuel filter if more than 30K miles (45km) old. Drain the
water in any case.
c) run a can of Techron, or if you can find it Chevron DELO fuel
additive through the system. Follow the directions on the container.
Fill up with fresh diesel fuel when you do this.

You may also have gotten some high-paraffin diesel (high-wax content),
AKA "summer fuel" and/or additive-free heating oil. That stuff _WILL_
smoke although in theory it should do no harm to the engine. What
happens is that suppliers sometimes (rarely but it happens) mix up at
the yard, especially if tankers do double-duty, delivering heating oil
some days and diesel some other days. The sovereign cure for this is to
add a few gallons of kerosene (up to 1/3, as it happens) to thin out
the diesel. NOT GASOLINE. NEVER gasoline. This also helps with winter
starting although your mileage will drop some.

Peter Wieck
Wyncote, PA

Hi, the smoke is grey,it smokes any more than 1/4 throttle to full , lots
of smoke then it clears. The car pulls well but smokes when accelerating
and has a flat spot just under 2000 revs.The car was serviced sept last
year about 2100 miles ago.I live in England its cold and wet at the
moment.I use the same fuel station every fill up.Thanks for your help.

What color is the smoke?
How much smoke is there?
When and for how long does it smoke?
Where are you (climate)?
When did you last change the fuel filter?
Is the smoke concurrent to a recent fill-up?

Peter Wieck
Wyncote, PA

IVE JUST CHANGED THE AIRFLOW METER ON MY PASSAT, ITS STARTED TO SMOKE, THE
CAR HAS DONE 66K ANY IDEAS ?