Radak

I've been meaning to post this for a long time, but never have. It's been getting worse, though, so I think I will.

My car does something pretty odd, which I can reproduce fairly easily. If I load the engine a little bit (say, put myself in a gear too high and press on the gas) and try to maintain around 7 psi boost, the engine will start making a funny chirping noise, and I can watch the boost gauge bounce 7-4-7-4-7-4-7-4-ish. Each chirp sound is associated with a loss of boost, and the cycle takes make half a second, so it's a fairly fast oscillation.

This behavior has stayed with the car through two sets of turbos, three sets of BPVs, and half a dozen different software loads. It is generating no DTCs.

I've searched the archives, but haven't been able to locate anyone else describing the same situation. Unfortunately, since "chirp" is the best word I can choose to describe the sound it makes, all I find is everyone showing off how fast their cars accelerate.

Anyone got any ideas?

S4mig@PEB tuning

Ever replace the N75 valve?

donp

Are the throttle body boot and F hose (if you have one) intact?

Radak

No TBB (BiPipe) and F-hose is the Hoppen part (and is fine)

Radak

Nope. I've got a spare, though, and was considering trying that.

VonK :: Retired

Make sure the fragile silicone hose to the wategate is OK. Mine opened small cracks under pressure.