Hi ppl,
Last night I was giving my classic wrx some up the road in 2nd & 3rd gear but when I went into 4th I just drove sensible i.e 3000rpm but while slowing down & going round a round about I heard a loud bang & as I pulled away from the round about my car started jurking so pulled over to the side, just as I was doing so it cut out. Managed to get it started again but the revs are all over the place, anywhere from 700-2000. Thought it might be a sensor problem but done the check with the ecu & engine check light & none came up but when I drive now I can hear air escaping through the dump valve even when Im not boosting every time I come off the pedel or change gear & when I slow down for a junction or stop at light the revs start to get all eratic again & sometime's the car even cuts out.
Has anyone else ever had this sort of problem with a dump valve, Im going to put the standard one back on when I get home from work today to see if this rectifies the problem. If not Im totally lost as to what may be causing the problem.

Keith

p.s The dump valve thats on it the now is a Forge one, is this a good or bad thing?

 

Sounds like the diagphragm has split and is leaking air into the inlet. If you have a piston type DV, the piston may be stuck in the open position, again leaking air into the inlet. The blank for the original dv may have dropped out also.