Hi
I recently bought a Non Running 1999 Audi A6 2.5 V6 TDI with 145k miles (AFB Engine code) with the complaint that the Injector pump was faulty, (Bosch Vp44 pump), however I managed to get the car going as the fault was in the Engine ECU .The car now starts on the first turn of the key and runs with a slight vibration until warn when it is totally smooth, but this is when the problems start:-
When warn the smell from the exhaust is of pure diesel and a mixture of white, blue and black smoke appear when the throttle is pressed, (enough to fill the road and make every things disappear)
The Turbo has been away for a service and reported back as being in Very Good Condition – but then the car is idling down after having blipped the throttle - there appears to be a back pressure on it – the cat has been removed as it did appear to have been “tarred up” from a previous time
The timing marks on all the relevant places have been checked and found to be all ok; the Crank case oil breather has been removed and replaced
The MAF has been replaced as it showed up on Vag Com as being faulty along with the Lift Needle Injector having been checked for resistance (approx 80 ohm’s) as it appeared on Vag Com, intermittently
The EGR system has also been removed to prevent it from causing any problems
There is no coolant loss either


Any help on this matter would be appreciated
Regards
Martin

 

I don't know much about diesel engines, I wish I did so I could help you. Sounds to me like you aren't getting complete combustion though.

 

I saw no mentioning about the oxygen sensors?
Are they present, functional?

Do you have a single cat application?

What are the current DTC?

 

Do you hear the turbo spooling up when you accellerate? the smoke you describe is serious overfueling if the turbo is spooling up as it should then you need to be looking at the injectors/injector pump

 

i forgot to add that i have replaced the maf and checked for any faults with Vag Com (version 10.06 - latest) but the system is clean , there is no lamba sensor to cause any problems and i am going to try running the car with the exhaust removed (splitting it just prior to the middle box)to isolate any potential of either exhaust silincers being blocked
the turbo is spooling up very neatly