nom

B100dy flood control. Try answering & it says 'sorry, you're talking too much. Go away & come back when you've forgotten what you were talking about'

[Edited by nom - 12/1/2003 9:18:45 AM]

Iwan

Hi all,

I have a MY99 which i've owned for all of a week. I'm starting to get used to it now but have noticed something it does when sitting at traffic lights, or when idling for a minute before shutting the engine off.

Normally the revs are pretty stable at idle but occasionally they 'hunt' (go up and down a bit) for around 10 seconds then return to normal.

Is this normal behaviour?

SiDHEaD

I'd keep an eye on it. Mine did this for a month or so, probably the ECU covering up for the error on the MAF (mass airflow sensor). and then when I had some other work done they had to reset the ECU. This caused it to forget how to cover the error, and the MAF was actually nadgered. One new MAF sensor on warranty later and all sorted.

Andy

Iwan

Cheers, i'll keep an eye on it. It's a Subaru Proven used car so it's got 2 more years parts/labour warranty on it.

Heh heh ;-)

scoobyslut

i'd get the car booked in to a dealer and get it sorted as it wont do your fuel consumption much good, plus if it ever cuts out on you at a junction [next stage of failure] it may not seem so minor a problem.

Iwan

Hmmm, probably a good idea.

I know this may have been done to death in other threads but if the MAF is on its way out, what sort of MPG would i expect to see?

On the first tank of fuel i averaged 16MPG (heavy right foot), but this weekend i did a motorway trip (85MPH ish) and averaged about 22MPG.

Cheers all.

nom

That's low mpg, IMO.
The MAF only governs fuelling at positive boost, not at a cruise, so it's unlikely to make a particularly big difference there. Anyway, the MAF fails by reading low - ie the engine leans out, not richens up, so the car would slowly get quicker & quicker until the engine blows...
It's tricky to work these things out without any readings from the ECU - idle mixture I believe is measued by lambda & MAF, & uneven idling can also be caused by a dodgy idle stepper motor.
On MY00s, the original MAF is a known weak point, & it going wrong can have catastrophic results. Lambda probes are consumables, but are not noted as such (and so are not replaced regularly as they should be), and will cause bad economy, but little else unless left like this for a very long time in which case it's technically possible for the rich mixture to cause bore-wash & you get a sticky piston...

KMH

Hi

Had a similar problem with my MY98. It turned out to be the idle control valve. Hope this helps.

Kieran

Iwan

Cheers for all of the tips!

I dropped it off at the dealers last night and they are going to look at it today. Hopefully whatevers wrong it'll be done under warranty. Having said that, if its the Lambda sensor and these really are classed as consumables, how much are they for an MY99? I had one replaced a few years ago on a Fi*t Tipo and it was around £120 at the time...

scoobyslut

As far as I was concerned the lambda sensor is covered as well, cant really class an electrical item as a consumable, i'd back off on that one if they tried it on me. If on extended warranty, it will definately cover it, as they are around the 90.00 notes mark plus fitting if bought gen and it would have to be for the warranty.

Iwan

Thanks Scoobyslut, if they change anything then i'll "suggest" that it's done under warranty. Mind you they seem pretty good there so doubt if i'll have to ask that.

Hopefully they'll be ringing me back this morning when they've had a look, so i'll post an update on what they found.

Dark Blue Mark

Got my Lambda under warranty.

MB

Iwan

Just picked up the car, apparently it was indeed the MAF sensor on its way out. Has now been replaced under warranty, and they also carried out the ECU reset i asked for (for using Optimax).

Thanks to all for the advice, and thanks to Simpsons for a job well done.