B6 A4 1.8T squealing noise from suction jet pump?

[paul187]

My B6 1.8T A4 has a squealing noise coming from the suction jet pump, or in this area. The noise is only heard when the car warms up and only under vacuum (when engine is under boost the noise goes away).
Things I have done already:

Replaced the suction jet pump
Replaced the PCV
tried removing the lines around the suction jet pump and running the car

See attached video.

The only thing that has worked so far is removing the suction jet pump and running the car.

Any ideas? I have run out of ideas, If not please send me a link to a manual which shows good schematics of the system so I can troubleshoot further.


https://www.youtube.com/watch?v=UX_tIMmCKUo&feature=youtu.be

[paul187]

Anyone got a good schematic of the 1.8T vacuum/boost setup?

[vacsimile]

I just Google image searched "Audi 1.8 vacuum diagram" and got lots of them. Sift through them and find your engine code.

I'm thinking one of the many check valves is stuck open or installed backwards. Pinching off various vacuum lines while the engine running is a good diagnostic technique for this kind of problem.

[D9n_dk]

Hi sorry to drag up an old thread but did you get to the bottom of this noise I've got the same thing but mine isn't so constant like yours it's only when it's warm and I come off the throttle either slightly or heavy it does this noise for a couple of seconds and stops. Can anyone help me?