Need some help troubleshooting an over boost condition on my S4s - under WOT and high RPM the ECU is cutting the fuel due to too much boost. Boost gauge pegs and then quickly drops to zero just as ecu cuts fuel.
I've checked the wastegate hoses for leaks and found nothing, disconnected the wastegate solenoid and she runs a pretty steady 0.65 BAR under all conditions, which I believe rules out the capsule?
I took the wastegate soleniod off the car and it looks grimy and the foam filter has pretty much fallen apart. So, I'm thinking it sounds more of an electrical vs mechanical boost issue. I was going to replace the wastegate solenoid next, good idea, bad idea, any suggestions or help appreciated!