Join Date: Jan 2006
Location: Alexandra, New Zealand
From your description it would seem the IAV is not controlling the air supply as its wide open. This can be because of an ECU fault, wiring or simply adjustment. I seem to recall a lever on the side which can alter spring tension. Think I set mine to full on so it would remain closed under boost. Might give that a try as I didn't see anything on the valve adjust in BGB.