Cold Start TDI Smoke

[PDL]

Hi Guys has any of you noticed if your passat 2.0 TDI when started from cold gives out a cloud of diesel smoke from the exhaust.

It also starts little rough.

Its not oil smoke as its smells very strong of diesel and its not steam.

If i leave it running for 5 mins then switch off and start again there is no smoke?

I have no error codes and the car drives and ticks over fine.

Any suggestions?

[james_tiger_woo]

How cold is the car when you start - is it a proper cold start? Does your car get full, long runs to warm the engine up? Is the oil level right and fresh? Do you let the engine run a little after a drive to ensure that oil doesn't sit in the turbo?

It could just be the cold affecting your engine.

[gamichea]

In this very cold weather you may well get a little more noise at idle. The idle speed should be a little higher as well implying more fuel is being supplied and probably contributing to the increased diesel smell.

Some of the 'smoke' will be condensinsing steam generated from the water which is a natural by product of the combustion process and will be most visible until the engine and exhaust system heats up and the effect is exacerbated by the cold air temperature like steam in the kitchen condensing on cold windows.

I try and leave the car idling cold as little as possible by using a scraper and de-icer rather than relying on the the warming interior to clear the glass. Its kinder to the car and the environment.

[martin1810]

I would get the glowplugs checked just incase. In theory a faulty one will show in a scan but I would double check any way. It would also be worth getting the glowplug relay checked if the plugs prove ok. The glowplugs are designed to run for up to 4 minutes to help prevent unburnt diesel.

[Quatrelle]

You don't say how old the car is and its mileage.

Do you wait till the glow plug light goes out? Give it a second or two more before you try starting it.

Does the engine fire the moment the starter moves? On my old Laguna, I hardly hear the starter - the engine fires the instant I turn the key. On my Passat, although it takes no more than perhaps a second, it's long enough to hear the starter turning the engine - time for a couple of cylinders to suck in more fuel than it necessarily needs before it catches, hence the smoke.

[kite]

Operate the glowplugs 2 or 3 times before cranking

[PDL]

Hi Guys the car is 2005 done 60'000 miles.

Smoke is instant as soon as you start . Then its gone .

Have tried leaving glowplugs on longer and also taking key out and back in makes no difference.

Its like one of the injectors has been leaking into the cylinder and then when i start it up it comes out the exhaust.

Once it has been started once then if i started it again there is no diesel smoke straight after.

It is defo diesel smoke though head has not gone.

[martin1810]

Get the glow plugs checked. Maybe only one has failed which would give you one cylinders worth of unburnt diesel for a few seconds.

[vroooOOOM]

I'd say check the glow plugs first as a staring point, I had a similar problem with a jeep I owned, if you can locate the glow plugs remove the wire (engine off of course) and check the continuity and resistance with a electrical test meter if you get no resistance or no continuity the plug is dead (open circuit).
if you don't have a test meter, you could try this but be carefull not to touch anything with the + wire: remove the connectors on each of the plugs,run a test light,from bat+ and to the glow plug,if the lamp lights the plug is ok,if it doesn't then it is dead.

[bundao]

If the glowplugs are still made like the ones on my old mk3 astra their functionality reduces long before they actually fail completely.