hello,
I have a 1991 Jetta Diesel Turbo it wont biuld up boost it...i checked if turbo is good it is (no shaft play) and it will spin when engine is on and get fasterwhen the rpms go higher like it should but i cant hear it build up or anythin and the car feels slugish......
btw i found oil in the intake and on the turbo i cleaned it and the car picks up better but wont build boost,....
is it the WGA
wat can i do thx
5spd 200 000kms
Its not seized it rotates but wont build boost....If i runs engine with intake pipe off it can feel the air movin from it so its fine and no shaft play turbo is in good workin order but....it wont build boost...
The wastegate may be seized up. This often happens on high-mileage turbos with poppet-type wastegates, because every poppet-type wastegates use some of the pressurized engine intake air blown around the wastegate valve stem and guide to keep the wastegate valve cool. After lots of age and miles, some oil droplets make their way into the high-heat wastegate valve stem/guide area, and evaporate, leaving behind a gummy varnish build-up that slows the reaction of the wastegate, can prevent it from completely closing, or can even freeze it up entirely.
If you have a turbo with this problem, the fix (besides finding another new or well-maintained used turbocharger to replace it with), is to take the turbocharger apart and rebuild it, either hiring someone to do this job or doing it yourself with one of my
Dieselicious turbocharger upgrade/rebuild kits (includes parts and instructions.) You can also take the turbocharger apart and just clean its wastegate valve without needing a turbo rebuild kit, but IMO if you're going to take the turbodown apart that far, it makes very good sense to rebuild it completely (installing new thrust and journal bearings and seals.)
Hope this helps, and good luck.
Edit: moved to troubleshooting section