Possible failed wastegate actuator?

Question

Arrrggh! What happened by boost?My top boost has dropped from 0.8 bar to 0.5 bar and my basic boost hasdropped from 0.35 bar to just under 0.2 bar.My boost curve has altered as well - it used to dip slightly somewhere after3000 RPM and tail off to about 0.5 bar somewhere around 5000 RPM. Now ittails off dramatically at about 3000 and pretty much basic boost levelsthereafter.I have tested the APC box by upping the F & P pots which does give me aslightly higher boost, so I think we can discount APC box problems. Giventhat the basic boost has dropped I looked at the wastegate actuator and I'msure there was more thread there before. Whenever I've adjusted the itbefore, I've gripped it with a mole grip and then adjusted the nut and endarm. I can only just get my smallest mole grip on now and there's no room toadjust the nut.Has my actuator failed? The car is going into my garage tomorrow, so if thiskind of behaviour fits with a failed actuator, I can hopefully have themreplace it.Your advice would be very much appreciated.Paul1989 900 Turbo S

Grunff · Accepted Answer

Hmm, dunno, doesn't sound like the actuator. Have you tested it? Disconnect the vac hose which goes to the actuator, and suck/blow. Anything?

Paul Halliday · Answer

in article      Grunff at     wrote on 12/10/03 4:26 pm:Which way? Disconnect from the APC solenoid and suck/blow on the pipeattempting to affect the actuator?What should happen? If air passes then the diaphragm is done? Is there aspring in the stock actuator that could've broken or suddenly gone weak?Questions, questions. Thanks Grunff.Paul

Grunff · Answer

Yes.Yup.There is a spring, yes. I've never come across a broken one. But it is possible.

Paul Halliday · Answer

in article BBAF0BC4.A875%     Paul Halliday at     wrote on 12/10/03 1:46 pm:My garage, in passing conversation, inform that the actuator has gone soft.They've advised I invest in an uprated actuator. So, who am I to disagree :)Thanks for the replies.Paul

Possible failed wastegate actuator?

Join the Discussion

Didn't find your answer?