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Had my RS2 on the track at castle Combe for a few laps when suddenly noticed from the boost gauge that the car was under boosting.

My car has been mapped by Mihnea and produced 20 psi upto 4000 rpm with boost then increasing to 25 psi thereafter to redline. It now will not boost past 10 psi.

Have had the codes taken from the ECU and there was some minor stuff. Anyway, checked all sensors and reset the ECU but the result is the same. No more codes are appearing on the ECU.

Have checked all hoses (10 times!) and pressure tested the intake system. It holds pressure well so no big leaks.

Only thing not yet changed or tested is the WGFV (I have a spare one to try on it) and the wastegate diaphagm which I know can split.

Other than that, has anyone got any ideas as I am running out of inspiration!!!

Try disconnecting the WGFV, then you will only get what the WG is set for ( ie spring pressure - normally .4 to .6 bar ) Is this different to what you see with it connected ? . If your WG diaphragm was split you would be overboosting. Try cleaning the MAF electrical connections and reset ECU.

jameswkr wrote:Try disconnecting the WGFV, then you will only get what the WG is set for ( ie spring pressure - normally .4 to .6 bar ) Is this different to what you see with it connected ? . If your WG diaphragm was split you would be overboosting. Try cleaning the MAF electrical connections and reset ECU.

Ok. Will try and report back!!

jameswkr wrote:Try disconnecting the WGFV, then you will only get what the WG is set for ( ie spring pressure - normally .4 to .6 bar ) Is this different to what you see with it connected ? . If your WG diaphragm was split you would be overboosting. Try cleaning the MAF electrical connections and reset ECU.

With it disconnected the boost is only about 7 psi so I guess the ECU is controlling the boost to some extent. The fact that it is not controlling it to limp home values, that there are no codes and the ecu has been reset (the diaphragm is fine and the MAF connections have been cleaned) kind of points me to tubo failure. Have inspected the vanes on the inlet side but it all looks ok so not too sure how else to check it without removing it?