kelisko

This could help: https://www.audiworld.com/forums/a6-.../#post24276198

Dryrotted

IMD I am tracking this down in the same. What does B in the diagram actuate? In a new purchase for me this rubber adapter was disconnected from the upper intake manifold and had tape on it. As soon as I reconnected it a load clacking is hear for the upper intake center approx.. I thought it was the tensioners but it seem sit is this vacuum connection. Any idea what it controls or what would be in the upper intake it controls.
Thanks-JH

kelisko

B supplies vacuum to the intake manifold (IM). The IM then sucks on the EVAP canister purge valve which can click and clack when bad.

C supplies vacuum to the leak detection pump (LDP) which is hidden under the driver's side rear wheel housing liner.

Vacuum is generated by the vacuum pump which supplies vacuum to the brake booster as well as to the IM and the LDP.

Dryrotted

Ok per the other thread where I sent pictures if this B actuates the purge valve it is possible but the sound still comes from center of the intake not the back. They are only $30 US so maybe I change it anyway and see what happens.