What makes the WGFV go clickety click?

[newsh]

If I open the throttle suddenly at low rpms the WGFV goes tika tika tika tika. I've been noticing this noise pulling away when cold sometimes and thinking it was something mechanical, then I noticed it was doing it just revving it at rest, then some of the chaps at CC sussed it was the WGFV. Weird.. We tried another WGFV but it was the same. Could it be an ECU or mapping problem?

[Ducky]

You can find a test procedure of the WGFV here:

https://www.s2-audi.co.uk/tech_articles/motronic/wgfv.htm

[andrewd]

In my limited experience, it seems normal for the WGFV to start ticking as soon as the turbo wakes up, even revving at rest. The ECU is modulating it to try and spool the turbo up quicker and then to modulate the boost. Not sure if yours is abnormally noisy, but mine is just about audible with the bonnet up?

[s2driveruk]

hmmm I wonder if this is what I can hear in mine rather than the cam chain as they are fairly close together....

[newsh]

This is a real hard tick, not a buzz from a PWM signal. It sounds like a broken CV joint but doesn't change frequency with speed or RPMs.

[Ducky]

I guess you could always unplug it and see if the car still 'ticks' when you rev it? I've noticed my RS2 ticks from the front when revved off load (bonnet up), and I only had the belt+tensioner done a few thousand miles ago. The sound comes from around the right area (by cam belt cover/behind headlight), I just haven't had time to investigate.