Cret

It had been hesitating under acceleration the last few weeks but has suddenly begun to cut out and the idle to rev up & down quite a bit sometimes just after you pull up at halt signs/lights. Also, my check engine light flashed on for a few seconds yesterday then disappeared again and I don't think has come back on since. When it cuts out the tacho needle drops to zero then flips up again when it goes again (unless it causes a stall).

This afternoon it cut out several times and started up instantly most times but a couple of times it sounded rough as hell, as if it was only firing on two.

When it's been cutting out it's also been emitting the most incredible backfiring, that's had people running for cover! Sounds real bad when it's been going off, with almost machinegun like blasts at times!

If anyone can help I'd be grateful as I don't really trust the car at the moment as it nearly cut out whilst I was pulling out of a busy junction earlier!

BTW it has an ITG panel filter but it's been in for absolutely ages so I wouldn't have thought that was from having an aftermarket filter really.

Any suggestions?

I've done some searching and common suggestions for this kind of this seems to point towards possibly either coils or MAF sensor but how do I test these bits to see if they are knackered? I don't have anyone I can swap bits with for testing by process of elimination unfotunately.

Cheers guys - want to sort this out as quick as I can before it stalls in a really bad spot!

ktomass

Which MY is it?

Kristijan

Cret

It's an 89 RS Legacy

Going to try cleaning the MAF first I think & see if that helps at all....

ktomass

I had similar problem and it was fuel pump (if it is still original one check what is fuel pressure you get to the engine) next would be coils and earthing.

I read again your original post and yes you should check your MAF too, although they are quite durable up until they changed it for MY99-00 Impreza.

K.

vulnax999

iTrader: (7)

I suggest MAF, maybe lambda sensor.

If you do an ECU reset and count the pulses, you can see what errors are stored in the ECU. The codes and meanings are on saxonfields website
http://www.saxonfields.freeserve.co....e.htm#_Sensors

Cret

Hopefully I'll be able to test a few things out on it this evening if it's not p1ssing down!!

I did buy a walbro fuel pump on Ebay a short while ago but the w@nker ran off with my money despite having previously good feedback and so on. Anyone know a good place to buy these in the uk? I think it was a 255lph job but wouldn't know the part number.

Cret

Cleaned the MAF last night and the cutting out/stalling/hunting idle problem appears to have gone!
It's still hesitating when I try to accelerate at any decent rate but not when I accelerate very gradually so I've now to figure out what that is and I think a new set of plugs will be the first on the list to try.....

Cheers for the comments dudes!

ktomass

Glad you sorted it!

Hesitation on mine was caused by lambda sensor not working properly (haven't got CEL though). I changed that and all was fine ever since.

Also try to reset the ECU now the MAF is clean.

Kristijan

Richard Curtis

I have had two causes of hesitation on my UK MY97:

The first was under hard acceleration only - this was due to the spark gap being set too big following a service, adjusted the gap from 1.0 to 0.8mm and all was well.

The second was only under mild acceleration (ok at full throttle) - it was the lambda sensor (The ECU does not use the lambda info at full throttle).

From your symptoms I suspect the ignition system - I think the old legacy turbo had 4 coil packs, one on each of the plugs, maybe one of them is packing in or you just need new plugs.

messiah

see what your CEL says - it can point out problems even if it's not flashing.

Cret

Cheers dudes. I've been trying to work out the proper connections for my ecu diagnostics but I cannot find black connectors ANYWHERE, only the green ones. There are I think a pair of white ones though down near the pedals so it could be that I have a freak car with different colour plugs as even Legacies normally use the same colour ones as Imprezas...

Yes it has got 4 separate coil packs and they are renowned for breaking down according to the Aussie guys on the RSliberty forum where they're all into Legacies.
I will try a set of plugs first though or cleaning/regapping the ones already in as I've no idea how old or what state they are so it may just be that......

ktomass

On my car those black connectors were pluged in and taped over under steering column, so you can imagine how "easy" was finding them. :-)