[dvldoc]

The boost bypass valve is about the only thing that will keep the M90 from producing boost. Does he have a aftermarket boost gauge hooked up and hooked up correctly?

Second there are several vac lines that can come loose on the supercharger that can bleed off alot of boost.

M90'S are nothing more than a big air pusher they have to make boost if they are turning and the bypass valve is functioning properly and the coupler in the snout is engaged and turning the rotors.