Hi,

I own a Ford Sierra Cosworth with a 330-kit and now im having problems with the turbo. The boost is not what it should be and only shows 0.3-0.4. Ive tried fiddling with the wastegate and bought a decompression valve, and it doesnt work. I changed the dump valve and checked all connections for leakage.

Is there someone out there who can give me a list of probable causes?

Thanks