My A4, B7 2.0 TDI (BRD Sad) 170 BHP have lately been given a lot of problems. (all Siemens injector replaced with x-models)
10 days back it would not pick up speed like it was having a trouble spinning up the turbo. It started smoking heavily and the DPF started giving warning light and it went into limp mode.
Got it home and found the well know problem "P0299 Under boost" Did all the easy checks for: vacuum leaks, turbo to intake pressure check. Checked all the vacuum actuators and finally changed the N75 and also the intake switch valve. Still no solution. (Changed the diesel filter and airfilter just to be on the safe side. )
At this time the car could not even idle for more than 10 sec.
Car have done 110k and sofar I had not suspected the turbo as it seemed to be spinning nicely on the intake side. I got the idea the turbo could be jammed on the exhaust side and the connecting axis broken. (Audi confirmed that it happens now and then ..) Got the replacement turbo mounted by still the same problem Sad By now I was sure it was the DPF. Cut cleaned and remounted.
Car ran like a dream for 24 hours then the same problem again... Today..
My theory is the DPF is again getting blocked by oil coming from intake due to high positive crankhouse pressure in the rocket valve cover due to worn piston rings or perhaps leaking injector seats/sealing’s/o rings ?
The CVS is blowing heavily from the rocket valve cover to the turbo intake and even when removing the filler cap a lot for air coming and even "oil-spray"
Any one pls. comment on this "nightmare" I hope it is due to the injectors letting compression into the rocket valve cover and will next go for compression/cylinder leak test.
Any other ideas ?
Long story in Danish-English Smile