losing boost and wierd sound...any ideas?

[aaronb416]

Have a 02 1.8t with apr chip, full exhaust, CAI, power gasket

The problem is that a couple days ago a wierd sound arouse. Its a whining sound, almost like a supercharger sound, but it happens whenever I accelerate. It gets louder the more I boost. Another issue that started the same time as the sound was that I use to spike 20psi and hold 16-17, and now I only spike 15 and hold 13-14.

Any ideas?

I was thinking maybe blown diverter valve or boost pressure valve?

[CO AVANT]

check the DV. do a boost leak test. All you need is a tennis ball and air compressor (clamp off hose to crankcase, use no more than 30psi). Sounds like your turbo could also be taking a shit.

[phantom b6]

Yeah.. it very well could be the DV. If not, probably the turbo. Swap DV's with a friend if you could.