Dave_RB5 #92

CAR: Impreza RB5 Prodrive, straight through exhaust system. Has been running great and still does on throttle!



Could anyone shed some light on my problem…



About 1 week ago my engine check light came on, I stopped and turned the engine off then back on and the light went out. I called into my local dealer where they checked the fault for me which indicated the oxygen sensor...the technician asked me if I was running it without any cats to which I said yes as I have a full system. He said that was why the light was showing due to the down pipe not having the sensor connected to it. He then said it may come on again in the future but not to worry about that fault.



So, my problem…since I’ve owned the car (8months) the revs seem to go between 500rpm – 900rpm when I blip the car to around 3000+rpm then it will settle back to 900rpm after 3 or so times running around 450-900. It also does this when I’ve been driving fairly hard then stopping. This I thought was the ECU making changes as the turbo was spooling up/getting hot etc then running back down to idle revs.

However, since the cold weather as come in (or my engine light as come on) its seems as though the above as become worse, resulting in one stall in traffic conditions. For example when moving in traffic I’m slipping the clutch moving along with the revs going to 1500rpm, then when I dip the clutch the revs drop to 300rpm sometimes 100rpm (stalled once). If I blip the throttle the revs bounce back up and go back some normal idle or it can carry on running up and down the revs untill i move off again.


Sorry about the lengthy post but I’m hoping someone might be able to help



My only thoughts have been the cold weather as an effect or the MAF is fu*ked????



Thanks,

Dave.

Barnesy

Sounds like a MAF problem, do a search plenty of info about lumpy idle and MAF's.

Jolly Green Monster

iTrader: (4)

what he said.. MAF sensor.

Also the Lambda sensor and decat is bollocks..

Dave_RB5 #92

THANKS FOR THE REPLIES! NEW MAF FITTED AND NO PROBS!!!!

Would running a duff MAF caused any engine damage???



What else would it be then???

Cheers,
Dave.

Jolly Green Monster

iTrader: (4)

if the car is running okay then you got away with it.. yes a faulty maf can cause engine damage.

the lambda failing or a wiring fault. or because the maf was causing the car to lean out so much the lambda sensor was causing the ecu to add lots of fuel and it hit the limit causing the ecu to suspect a problem and point the finger at the lambda sensor.

see if it still happens now the new maf is fitted. imho

Dave_RB5 #92

Understood! Thanks mate top info!!! So i shouldn't have any lasting damage?

Jolly Green Monster

iTrader: (4)

fingers crossed.

mark28

i have the same sort of problem apart from my engine does not hunt. if i am driving along and come to stop with the clutch dipped the revs drop down almost to slalling point. but then bounce back up to normal. today i put a new MAF on it but this didnt solve my prob. (nevermind there is always tomorrow ) it is almost as if the idle valve can not work as fast as the rev's drop. maybe someone has had this problem and can remember what they did to fix it

Barnesy

Make sure you reset the ecu after fitting new maf.

mark28

done that. how about coolant temp sensor ? cos only does it when it's warm so its something to with the fuel side of things. lol