Butterfly valve in 2.8 tailpipe

[Dennisthemenace]

Does anyone have any info on this? The valve looks like is controlled by earthing on the grey/purple wire but mine does not operate at all.

If I ground said wire the valve shuts and the car is quieter. I’ve looked through the Bentley manual and tried to look it up on the internet but all I get is sodding golf tee mods!

I want to try and get it operating as it should, as it would be nice if it didn’t shout its fob off when you start it!

 

[Eddie Zedder]

Check the vacuum pipes and switch are connected, a lot are disabled as owners prefer the noise. The link is for a 2.0 but it's the same for the 2.8.

https://www.realoem.com/bmw/enUS/showparts?id=CL32-EUR-07-1999-Z3-BMW-Z3_20&diagId=18_0383

 

[Dennisthemenace]

Cheers Eddie,
Everything is connected, if I put the grey, purple to ground the valve shuts, I need to find where this wire goes to at the front of the car, and what controls it.