Ben2563

Below 4k RPM on low throttle it stutters and misses. I changed the lambda and this cured it for a week before the problem returned. Changed it again and the same happened. I changed the airflow meter for a brand new one, again this fixed it for a week the the problem creeped back. Afer 4rpm she flies and doesnt miss at all.

Therefore I can only assume its the ECU and changing these components brought it back in limits for a short time. Does this sound resonable?

I changed the plugs and they were coked up but this I believe is an affect of the overfueling rather than a cause.

Please help guys I cant fix this and its killing me. Can has now been like it for 2 years. When I did fix it for the 1 week it rolling roaded at 310bhp.

Cheers

Ben

Ben2563

bump

Jolly Green Monster

iTrader: (4)

standard ecu and 310???

are the injectors grey or yellow?

what mods?

Simon

Ben2563

Hi Simon,

Thats right, as far as Im aware standard ECU. The injectors are yellow, only modifications are HKS mushroom filter, stainless steel decat system from turbo back. Dump valve and turbo adjustment between low and high boost.

I have the print out from powerstation to prove the output.

Any ideas?

Jolly Green Monster

iTrader: (4)

try changing back to original dump valve.

sounds like the dumpvalve is perhaps openning on part throttle / lower rpm,
although the cured for a week is a bit weird.. but i would swap back to eliminate it as a problem.

Simon

Ben2563

Def not the dump vavle, I only fitted that 3 months ago and had it reconned by Forge. 100% definately not that. It feels more of fueling problem and the evidence on the spark plugs supports this.

Fuel pressure is ok. The reason I think changing the airflow meter and lambda made a difference is it brought the ecu back it tolerance for a short time.

Also you should know, when poerstation plugged it in, when this fault was happening they said it was constantly at lanbda 1 (max heat). This didnt change until we changed airflow meter and fault temporarily cured.

Jolly Green Monster

iTrader: (4)

if the dumpvalve opens and all the air meant to be in the engine and measured by the maf doesn't enter the engine what do you this happens fuelling wise?

yep mega rich, bogs and hessitates..

changing the lambda or maf won't bring the ecu back into tollerance.. it can bring the lambda sensor or maf sensor voltages seen by the ecu back into tollerance indeed.. but the problem reoccurred within a week so something else is at fault.

was ecu reset?

Simon

Ben2563

I appreciate your input on the dump valve but it def isnt that. Like I said was doing way before that was fitted.

Yeah I reset the ecu. Only cured temporaily when I changed Lambda then MAF. When at powerstation I didnt even fit a brand new MAF we used one from another Impreza.

This is why it has to be a sensor or something reading both hence I guessed at ECU. There is serious beer for whoever can fix this for me!

PS- when reset the ECU it seems ok for about a mile, then faults again. No warning lights have ever appeared.

Blacksimus

I had this problem during the last two weeks and I changed plugs,maf and was literally going out of my mind. So I decieded to buy a cheapy dump valve from egay to replace my turbosmart one and kaboom problem solved.

The turbosmart dumpvalve was only 6monhs old

Ben2563

But this was doing with the standard fitment thats what I dont understand. Unless, when standard fitment was on there it was the maf. Now I have changed the maf maybe the dump valve is causing it?

Ok, Ill remove it and see what happens. I have a stronger spring for my forge one, Ill try that too. Let you know. Thanks.