P1ScoobySnax

guys...

the p1's idle stabilisation has started to get a bit funny....ie

when i come to a stop and dip the clutch...the revs drop as if its gna stall then compensates again and rises.....this in turn makes the deffi oil pressure gaugue drop and rise..

1. What causes this?..is thee a stabilisation valve somewhere?
2. What should the oil pressure be reading roughly at idle?

Spirit

Don't know about the oil pressure, but both a faulty MAF sensor and a faulty oxygen sensor have caused unsettled idle on my STI recently

stockcar

would certainly suggest a check-over asap, sounds like a MAF issue..........

alyn

sketr1

My STi V3 did the same last week, the lambda + MAF both u/s

Dspeed

My MY00 turbo has exactly wt u described. Dead mass air flow sensor. The slightly less nasty way in which they go but test it straigt away.
Either remove the plug when the car is running and it should cut out, if it dosnt the maf is gone.
Use the diagnostic terminals under the dash.

StudentScooby

Get a MAF asap or could be rebuild time if running lean. P1s are a sod for it so i have read....

Playsatan

iTrader: (2)

Yup, 99/00's are famed for it, especially if you have fitted and oiled air filter or induction kit.

Do a search and you'll finds loads of advice.

Paul3446

This happened on my MY00, when I called the mechanic and described it he said get it in straight away or you may be looking for a new engine, turned out to be the MAF sensor. Cost about £80 IIRC.

Cheaper than a new engine!

P1ScoobySnax

Guys...took it to the local dealer this morning

Diagnosis - Faulty MAF sensor...replaced and all is happy.

Iwan

Doh, glad you got it sorted. Must read entire thread next time.

P1ScoobySnax

UPDATE UPDATE UPDATE:

got the car home after work and noticed now that the funny idleing appears to be back!!!

phoned subaru SGT in taplow - who said the ecu needs to have idle adjusted up slightly? is this right.....??

whats going on....

Took it down to SGT in taplow this morning as one of my neighbours knows a technician there.

Plugged in the fault finder unit - The error code was still present (23)
Cleared this and did a few other checks like the O2 sesor etc all ok
Re-setup the system.

Drove to work - still idling funny and dipping

Do you guys reckon a dodgy MAF sensor??


After work i took it back to bulldog - who said they could not find any fault code via the diagnostic unit.....

Service manager said that its nothing to worry about!! yet it never did this before and im sure its not right still.
He said to keep an eye on it and brig it back if need be for further investigation

what i did notice on the way home was.

1. When the aircon is on and at max fan setting - idle seems ok..does not dip even when revved up
2. When aircon off and fan off - idle dips like before

Could this be something to do with setting up the MAF? as technician did a setting up process with aircon on full wack as the idle needs to be compensated because aircon will pull the idle down.
or is the ECU needing to relearn etc?

or am i just talking rubbish...

Bubba po

Aother common fault that causes lumpy idle is a faulty lambda (oxygen) sensor. About £80.

Spirit

Absolutely, as I said before I had both. Faulty MAF first then when that was replaced it turned out the lambda was knackered too. It's entirely possible a failed MAF sensor can wipe out the lambda when it goes.

Idle only became unstable when the MAF was replaced, and also the lambda will often only show up as a fault after a very long journey. I'd definately recommend checking this next

JonMc

iTrader: (51)

I've not long changed the MAF, and the lambda is next, just waiting until I fit the decat. Good to hear that I'm on the right track.

Anyone know whether a bugeye WRX is a 3 or 4 wire lambda, I've seen universal ones for about £20 on fleabay

rooferman

iTrader: (6)

Might be worth cleaning the idle control valve..............worked on mine after changing maf/lambda/etc..

Spirit

Lambda is something I wouldn't skimp on to be honest, the really cheap ones can give false readings and cause as many problems as not having ones at all. They are generic parts so you don't have to buy direct from subaru, however I would definately buy a decent make otherwise you might as well not bother - you should still be able to pick one up for around £50-60

P1ScoobySnax

Thanks guys for the info......

the technician did check the Oxygen sensor..and looked ok..but if it only shows up after a long journey? maybe it could be an avenue to check.

Ive booked it back in to SGT to have a whole day to check it out.
Off to chicago with work from sunday for 1 week..so Not going to drive it until i come back and drop to the dealers.

Will clean the dumpvalve tomorrow tho to see if that causes any issues?