I have just fitted a Bailey DUmp valve to my JDM 1994 WRX Wagon, when the engine is cold it runs fun, but when then engine is warm after 10 - 15 minutes of driving the revs jumps between 200 - 1200 rpm and sometimes cuts out, if i remove the small pipe from the top of the dump valve the car idles fine but if I reconnect it it starts revving erratic again.

Also not sure if its connected but if you accelerate hard Dump valve works fine, but if I accellerate slowly the dump valve starts to constantly hiss with the throttle on at about 5000 rpm

Thanks

Chris

 

Is it a piston type because it sounds like its leaking ?

 

I think it is a piston type yes, it has a big grey thing that moves up and down when in use, (sorry to be a bit dim)

 

If it's constantly hissing at 5000rpm then that's a leak mate

Personally I'd sack it off and put the OE one back on again as it does the job fine.

 

took it apart just and theres like a rubber ring seal that goes around the top and this is damaged maybe thats the fault

 

Sounds like it. Try a second hand oe dumpvalve. Bout £20 from www.glenburgie-subaru.co.uk

 

Spoke to Bailey today they said they will repair and service it for £40 and give 12 months warranty so I may do that

 

Stick your finger up the inside of the dump valve is there a rod in there ??

If yes it is a twin piston & is the correct type , If not its a single piston & incorrect

Dean

 

ah its a single piston then