hello folks

iv got a '96 wrx slightly modified with a 3'' nurspec exhaust with cat-less downpipe, apexi induction kit and dump valve. its running a z4 ecu and PFR7B's gapped at .65

engine performs fine until you floor it at which point it coughs splutters and pops! if i back off then apply not quite full throttle it will pull through it. im not getting any crazy boost readings either (not exceeding .9)

after iv been driving the car about half an hour the fault isnt so obvious and sometimes not there at all where apon the engine pulls very well.. strange!

fault codes 11 23 and 24 were stored but havent come back since i reset the ecu approx 100 miles ago even though the fault is still there.

any ideas or suggestions would be very much appreciated.

cheers, doug

 

code 11-Crankshaft Position Sensor
code 23-Mass Air Flow Sensor Circuit
code 24-Idle Control System Malfunction

all of these are conman faults along with coil packs for early cars.
As your running an Induction kit which lowers the life of the early maf's id consider trying this 1st then looking into the other two, my icv packed up and caused the car to feel flat.

 

also coolant temp sensor went on mine and caused pops and bangs, but id deffo try another maff. as could be detting and we all know were that leads to!

 

sounds like coilpack or leads to me. classic misfire problem

 

i would try checking the tip of your coil packs i had a similar problem with my classics really noticed it as the weather got worse but would get better as the car warmed up. the plastic tips under the rubber were cracked 1 even fell apart as i took the rubber off. That was on a 96 wrx, may not be it but worth a look

 

btw for a cheap and quick fix which worked on mine for as long as i kept the car was electrical heat shrink it needs to be quite large i got mine from work but you can get it on ebay im sure, put that over the rubber and to about a inch or 2 above it heat and repeat i put about 2-3 layers on if i remember, stops it arking across to the head

 

thanks :-) will look into that just now,, i presume the coils when behaving like that dont throw up a fault code?

 

correct mate, when they start cracking/breaking down they react to the heat of the engine, hence running better/worse once the engine is up to temp.

 

i'll try that with the heat shrink first, got some in work too! cheers bud

 

the cracks can be hairline so take a close look

 

just took the rubber bits off the bottom of the coils and they're cracked.. thanks guys for your help :-)

 

what fuel u running on. had the same set up on mine and shell v-power made it do just the same thing. or it was just a dodgy batch of fuel. not using the v-power any more and its fine

 

the new coils sorted it mate