The_Judge

Can't really tell from the picture! Need some close-ups of the compressor outlet, wastegate actuator, wastegate solenoid...

Another thought, based on reading the above comments regarding "whooshy". Is your dump valve OK? Could it be sticking open, hence the noise, and lack of boost?

Regarding ECU connectors, could really do with at least getting the black connectors together, to make sure there aren't any fault codes. You say there are 3 black connectors, 1 female and 2 male? Are all 3 in close proximity to each other? Will both males connect with the female...?

freshtripe

Think I've got to the bottom of this one...

Yesterday I put a Dawes-type boost controller on the car to see if it would make boost with that attached. It did, but it seemed that I needed to screw it almost right in to make 0.9bar (the makers claim this setting should give at least 1.5bar) - figured I must be leaking boost somewhere...

Today I took the car for an extended drive - the odd glitch in idle had returned, but now I was also occassionally getting the infamous "moo" noise when lifting off after a handful of boost - dump valve, right? (my car is the fault prone MY97)

Am I right in thinking that a busted dump valve diaphram would also account for the idle "funnies"?

Anyway, I can feel a "what's the best (cheap) dump valve" thread coming on...

Thanks for your help Judge, Bob and Steve.

Eagle7

I unplugged my MAF as described and the engine carried on happily! How is this even possible, surely the ECU has no idea what fuelling to add?

I guess i need a new one then?

The_Judge

Basically the ECU has corrected the fuelling to such an extent that it's ignoring the values supplied to it by the MAF sensor (or the small amount of air flow isn't registering), so unplugging makes no difference to the idle. If you were to reset the ECU, you'd probably find unplugging the MAF would cause the engine to stall/nearly stall. You'd also probably find the car drives like a bunch of ****. Certainly looks like time for a new MAF...

warrenm2

Hi,

Interesting stuff. I have a MY99 classic, and mine idles at 1200rpm with occasional "cough". Judge mentioned checking the ICVS - whats that? Thx

Mark

The_Judge

Idle Control Solenoid Valve. If that had gone, you'd get a constant idle of 1200-1500rpm. But it wouldn't splutter or hunt.

Have you tried the MAF/lambda tests...?

warrenm2

no - roll on the weekend....

The_Judge

Definitely.

cefski

Excellent advice on this thread. Cheers

Kev

Peanuts

iTrader: (15)

whats the expected outcome of disconnecting the lambda/o2 during idle?

I pulled into the petrol station and thought to check the MAF, with the car nice and hot and idling steady at 800 I disconnected the MAF and the car stalled instantly.
I reset the ecu and it took about 4 feet travel to flash all ok.
Ive still got a tiny blip in the idle now and again when its hot, just falls 50rpm below usual and recorrects now and again.
before you say Im paranoid (I am!) the idle on my car has always been rock steady except for the last time I had to change lambda/maf as it was hunting/nearly stalling at junctions.

The_Judge

Disconnecting it during idle doesn't have the same instant outcome that disconnecting the MAF does. It's more to do with how the car drives after disconnecting it. When mine went, there wasn't much wrong with the car. A small amount of hunting at idle, and occasional surginess off boost/cruising. Disconnecting the lambda made things slightly better, particularly the off boost/cruising smoothness. Resetting my ECU took anything up to 10 minutes, but didn't give me an error code. Fitting the AFR gauge was the deciding factor. No activity whatsoever. New lambda, problem solved.

mo,s scoobymonster

hi reading this post what i would like to know is that could i buy the £70 maf sensor from the dealers for my 97 wrx? or would it have to bethe £200 job because you cant dismantle these. has anyone got any pics of the maf which can be dismantled plzzzzzzzzzzz

bluep

Been reading thread with interest.Have a 97 typer and when i accelerate or boost hard the car splutters until i back of and accelerate gently.This does not really happen when i build up speed gradually only near full revs.Tried maf test and car stalls so i assume this is alright.Could it be lambda or any other ideas? It is stopping me from over-taking or dropping a gear forfear of not having power to get past.

Bob Rawle

Disconnecting the lambda will have NO effect on anything at all for as long as the fueling is at or close to enough to provide steady idle, when mapping these earlier cars I always remove the oem oxy sensor so i can use my PLM, the ecu the sees a default voltage of 0.345 (ish) volts which tells it that ist "stoich" therefore no closed loop fueling works, I have never seen a car that refused to idle without the lambda sensor connected, if the maf is disconnected then trhe ecu uses "default" values, dependant on wether the car normally needs positive or negative fuel correcetio it will either idle ok or not so its not the panecea for maf integrity that has been indicated.

As an aside disconnecting the sensor normally provides for a much smoother drive although you may or may not get a CEL due to it. That has no effect of function and is just a warning btw.

cheers

bob

The_Judge

Bob,

- Are you saying this "test" has absolutely no bearing on MAF integrity...?

- Would you say the others are relevant?

- Is there anything that you can think of that could be added to the list?

Thanks,

Ade.