Mvdz1

Hello I have a tt 1999 apx 225 Quattro
I have a boost issue it will only give me 0.3 boost I've changed the n75 valve turbo catridge and checked that the recurc valve isn't stuck, every now and then I will get no boost at all 0.0 on the gauge, anyone got any ideas please as its getting close to petrol and match time lol
Cheers
Al

transman

From this part of the post, are you saying that you changed the turbo cartridge, as in the guts?
If you havent changed the turbo guts, it would be a good quick check to pull the intake off the turbo and make sure the compressor wheel is spinning freely. I had a volvo doing the same thing, and come to find out the compressor would barely spin.

Next, I would be testing the waste gate diaphragm, to make sure its operating properly. Sometimes the wastegate could be getting stuck open, or being pushed open if it has a weak spring.

Normally, I would suggest doing a boost leak test, but your car would give a p1297 boost leak code if it had one.

Hope this helps, Connor.