fredhot

I have a MY99,just returned from the bodyshop after an artic tried to reduce the overall width. Repairs excellent except I now have a problem. On the overun, once engine is warm the revs sink to zero, stalling the engine. Nothing on the engine has been touched and it is absolutely standard. If you catch the throttle the revs have to be kept on and gently let off to get it idling. On idle it still hunts +-150 rpm at a guestimated frequency of 30 cpm. Something has changed, either as a result of the bang or as a result of the rhs wing repair. Anyone got any ideas? The bodyshop is willing but this is not their area.

dowser

Where were they working on the car? If no CEL's maybe check all the connections from the charcoal cannister out? Or the idle valve connection between inlet and throttle (joins inlet by PS reservoir)?

Richard

SiPie

Lambda sensor has poss been damaged (prob only likely if downpipe has been removed), but the fact that the Air Filter housing (incorporating MAF sensor) lives on the right hand side of your engine bay would point towards a fecked MAF

myp1

sounds like the maf has been damaged(there is a school of thought that vibration can cause maf failure on my99/00).buy the cartridge about 70.00 dont buy whole unit

mega_stream

I'm on my 2nd scoob, both MY99's and I'm on my 3rd MAF.

Symptoms were exactly the same as you have.

fredhot

Many Thanks to all who replied. I am going to focus on the MAF (at last the investment in the works manual has paid off - I can spell "MAF" and also find it underneath the bonnet!). Does a failed MAF show up on a Diagnostic check?

ScoobyJawa

A failed sensor yes, a misreading one no.

The latter is more dangerous because it leans the car out on throttle. A misreading sensor can cause those probs you are having - only real way is to get Delta Dash or the Select Monitor on it to measure the CO2 readings to see if they are right or not, or try a good MAF to see if that cures the problems

john banks

MAF could be contaminated with vapours from the repair?

Also consider the lambda sensor.

You can check the lambda sensor by connecting the green underdash connector as per the SIDC FAQ and firing up the engine. If warm it should flash a steady on-off (even mark:space) after a few seconds, certainly soon after you are rolling. It will not do this if it cannot go into closed loop properly (ie lambda working).

Link to help:

http://www.ravensblade-impreza.com/m...agnosisegi.pdf

fredhot

An update on my quest to solve the problem of the erratic idle and , more particularly, the tendency to stall as you come off the throttle, thus leaving you approaching a roundabout with no power steering and no servo! Don’t try this one at home kids!

All the evidence seemed to point to it being the MAF sensor. However, there was still that niggling doubt that it might be one of the other suspects – Lambda sensor or Idle solenoid valve. On a request for a diagnostic estimate the local Subaru dealer was not forthcoming. “Could be anything, cannot begin to give an estimate, these things are very complicated”. Yes, ThankYou. If it wasn’t complicated and needed special equipment I wouldn’t be coming to you! After describing the symptoms a second time and mentioning that the MAF might fall under suspicion because of the introduction for MY99s of the Bosch made “Mk 2” I was told that was a load of rubbish. No names, no packdrill but this is the only dealer on the A246 to deny touching the coolant system on my daughter’s car when they had just invoiced for the coolant.

A different chaumiere de poisson at Power Engineering in Uxbridge. From the info on this bulletin board I asked for Mervyn. I was put through, described the problem (once) and was offered the opinion that it was either the MAF or the lambda sensor. Diagnosis would be £125 and they would be almost certain of fixing it on the spot. They were also willing to squeeze me in at a time I could make.

Now we get to the bit you’ve been waiting for: it wasn’t the MAF it was the lambda sensor. The job was done in front of me – I think I was lucky, but as a “real” engineer I do appreciate seeing real work and as a bonus, a view of the Delta Diagnosis and a printout showing that the engine does really put out the claimed donkeys. Expensive, but probably still cheaper than the alternative down the road and a lot more enjoyable.

Thanks for the lead.