Help!! Noise has returned.

[Pmol66]

Please could anyone advise me on whats causing this to happen.
Its a nice sounding fluttering noise after boost when the air is dumped but my local vw specialist say its the sound of air going back through the turbo. (which is bad) ...
i replaced the standard dv with a 007 recirculating forge which seemed to stop tho noise. Now a month later, its back. Im going to get it plugged in tomorrow to see what codes are coming up.
I thought these forge dump valves were bomb proof.
I had a mate in the car this afternoon, i tryed to show him the sound but it seemed fine untill it had warmed up then it came back. Now after a good run about all afternoon. Iv lost boost. Very flat! And the battery light comes on if i put foot down. Weather the two are conected. I dont know...

Thanks in advance
Paul

 

[s3 Hoggy]

First thing I'd do is check all hoses going to the dv I had an issue which sounds the same. On mine the vacum hose that goes directly into the top of the dv had a split in it

 

[Pmol66]

Cheers hoggy. I'll have a look at them.
iv just been told about the springs inside the dv. Greens for standard and yellows for tuned. Iv got a yellow one on the way so while im changing that, i'll check the pipes properly