Hi guys I have a 2002 b6 1.8t that won't boost the boost gauge has 5 hg vacuum from the nipple on the manifold then only goes to 1psi I replaced the turbo as seal was leaking new n75 valve new dv new crank case breather gasket and clip cleaned pipes no leaks if I plug my boost guage into brake booster other side of manifold or by the perge valve I get 25hg vacuum just mot from the nipple on top of manifold driving me insane any1 local to East Sussex that fix audi

Hi Wompa and welcome to the site.  Are you saying that the car's performance is way down because the boost pressure isn't getting through to the engine, or just that you aren't getting a good reading from the intake manifold nipple?

Hi thanks for the reply yes only boosts to 1psi and only reads 5hg vacuum

There must be something blocking the inlet air pipework between the turbo and the inlet ports if you're getting those good readings near the turbo but the poor one near the manifold and if there are no leaks.

 

It's got me stumped.  Maybe it's blowing into the crankcase vent system or maybe the EGR has failed open, but that would let as much exhaust pressure into the intake as intake pressure into the exhaust!