Smoke problem

[arnold]

Since a few days ago my td started smoking,i had the pump set up for absolutly NO smoke while off boost and just a nice little black cloud under boost @WOT.
It smokes when off boost even with minimal pedal movement and more then before when boost comes up.No smoke when idling.
The smoke is black and very smelly,its not a
huge amount but bothers me becouse it wasn't there before,even when driving at night with someone's headlights behind me there was no smoke when off boost,now there's a constant black haze behind me

Previous weekend when i started my car on a cold morning he started on 2 or 3 cilinders,puffing out big white clouds,after a minute idling it smooths out,
it dies if i dont use the cold start,this is probably just one or two glowplugs that died,although there only 4 months old.
Again probably a glowplug although both problems started on the same day.

Glowplugs will be replaced this weekend,i checked for feul leaks,air in feul,boost leak,pump timing,all good...One thing maybe worth mentioning : I added some atf to the feul (1/4 feul left in the tank) and the black smoke was a lot less,when i filled her up smoke was back.

Anyone care to share there opinions ?


 

[theman53]

check out your glowplugs like you said and see. If it still persists maybe it is an injector or 2 sticking after bad fuel? You could try changing the fuel filter/air filter and filling the fuel filter with atf to clean everything. Usually black is too much fuel or not enough air and possibly not atomized fuel.

[Turftech]

I'm buying the glow plugs being an issue, but as they are only 4 months old, you might have fouled nozzles.  I'm going by the fact that it smokes while running hot.  An easy way to test a glow plug is to use a jumper lead and touch each one in turn.  You should get a little arc.  If not, plug is likely dead.  Oh, and disconnect the plug rail or test wont work.

Just curious though...  How good is the fuel on board?  Might you have picked up a dose of water?  The foul smell usually indicates water being burned.  That will lead to a bunch of trouble if left.  Siphon off a cup of few litres after it has been driven around and the fuel well sloshed around and pour a ~cup into a clear jar.  Add 1/4 cup water and mark the water line after it settles.  Shake vigorously and let stand for an hour or two until well settled.  Usually a few hours.  Check the water line after that.  It should not show more water.  The water in the fuel will be attracted to the added water and settle out higher if there is in fact water present.  Even a slight rise is bad.  Leave it overnight to see if more settles out.  Then you get to purge the water from the system!  Ain't that gonna be fun?  If it is water, that explains all of your symptoms including the failing glow plugs. 

Good luck.

[R.O.R-2.0]

how does water kill GPs?

[Patrick]

Bad injector will cause smoke, AND fry the glow plug........ Just a thought. If you find tips melted when you pull the plugs, you better pull the injectors and get them tested at least.

[Turftech]

how does water kill GPs?

Detonation pits the coating leading to a short?  Dunno.  Just know it happens from experience.

[arnold]

Well i did the water in fuel test and there was absolutly no water in the fuel,i only fill her up at thrusted gas stations (texaco and shell only) but no harm done eh.
I pulled the glowplugs to find out one died,two of them had semi melted tips so i guess next to do is have the injectors rebuild,luckily i noticed the smoke on the first day,if i kept driving it this way eventually the glowtips would'v melted off and fall in the engine.


One more thing:when i start her up on a cold morning,using the cold start it fires on the first crank turns and idles smooth however when i then push in the cold start it dies within less then a second,like turning the key off.

Am i right in thinking when its not freezing the cold start advances enough to not need the glowplugs ?
Im talking 50F here (10 celcius)when it starts this way,when it's freezing it starts really bad and blows billows of white smoke

[Turftech]

Fouled nozzles will make for poor cold starting as the fuel isn't being properly atomized.  As far as the cold start goes, as the engine wears it will need every advantage for starting it can get!  50 F is a bit cool for a flat out no glow plug cold start without advancing the pump timing on an older engine.  But it shouldn't just shut down when the cold start is pushed in.  I'm thinking the timing is a tad retarded maybe?  Or the RPM's are a bit too low?  Maybe both?  Does your cold start nudge up the revs as well as the timing?  I know my 86 Golf NA had no throttle advance, just timing.  My 90 Jetta TD boosts both RPM and timing.  The TD will start "cold" with no glow plugs at 45-50 degrees with some cranking, maybe even colder?  And it won't stall immediately either, but my compression is quite good now.  The Audi might have something beyond my knowledge, but I still don't think it should just die when the cold start is turned off.

Have your injectors serviced, and replace the glow plugs is my advice.  I also find adding Howe's Diesel Treat keeps things smooth once you get the injectors done.  ULSD is hell on older diesels.

Cheers!