Discussion
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CLASSIC signs of an AFM problem Ben m'lad... would bet dollars to donuts that your AFM/MAF/MAP has gone tits up. Easy to go to a wreckers and pull one off another similar model for 20 bucks and slap it on.
Other possibility is an air leak after the AFM... unmetered air getting into the engine will cause a car to run extremely rough then die.
Other possibility is an air leak after the AFM... unmetered air getting into the engine will cause a car to run extremely rough then die.
Edited by Esprit on Saturday 3rd February 10:01
not as similar as I'd like!Ben, please keep us posted. My 96 Impreza n/a has an idle and mis-fire issue, though much more minor. From cold sometimes the revs don't drop until I come to a complete stop for 10 seconds. I assumed it was the MAF sensor, probably damaged by the crap pod air filter that just flaps around the engine bay on the end of the clean duct.
I have also has an occasional mis-fire under light load, 2500-3000rpm, I assumed the MAF or TPS and this morning it only started on 3 cylinders so I hope the problems aren't building up to a breakdown. I will try the fault code check.
Does yours also have the lighting problem? I keep seeing Imprezas driving on clear days with the front fog lamps on, I guess it must be a common wiring failure? ;-)
Dan
I have also has an occasional mis-fire under light load, 2500-3000rpm, I assumed the MAF or TPS and this morning it only started on 3 cylinders so I hope the problems aren't building up to a breakdown. I will try the fault code check.
Does yours also have the lighting problem? I keep seeing Imprezas driving on clear days with the front fog lamps on, I guess it must be a common wiring failure? ;-)
Dan
Something similar happend on my old Subi. Took it down the shop and they plugged it in to the computer to find it was a little sensor went bad. I havent got the service records anymore so I forget what the sensor was for. I got them to pull the platinum plugs to see if they were fine. They were a bit on the rich side, but gave them a clean up and put them back in. Cost < $100 all up to get fixed. Ran perfect and no flashing lights afterwards etc.
I'll post up on here once I find out what it is - car is going in wednesday morning to get checked out/fixed, fortunately under warranty though 
ETA - This is my third Subaru wagon and first breakdown, came as quite a surprise really. (Well first breakdown not counting a split radiator hose once on the old Leone, but then again that car was pushing 250,000km so you kinda exect that sorta thing)
Edited by GravelBen on Monday 5th February 06:46
Dan M said:
Does yours also have the lighting problem? I keep seeing Imprezas driving on clear days with the front fog lamps on, I guess it must be a common wiring failure? ;-)
Well it does sometimes, but seems to be affected by moisture - my foglights only seem to be on when its foggy/misty/rainy etc. Though mine are also aligned to be pointing at the road they way they should instead of up at the other drivers, so wouldn't be a problem if I did leave them on the rest of the time. Still want some big mother spotties for night-time gravelbashing though
GravelBen said:
Well the problem is solved, twas the airflow meter after all. Well done Esprit, correct diagnosis 
Well, it just SOUNDED right
Usually general rough running, especially intermittant like that is something to do with the metering of the air or the fuel... either your fuel pump was cutting out or the engine was geting confused... logic suggests it'll be the AFM/MAP/whatever your car has At least it's a cheap fix
Well I've got it back from the mechanics now with a loan MAF in it while they're getting mine reconditioned and it still doesn't seem quite right though - Much better, it actually idles and runs now, but at idle the revs are swinging back and forwards between 14-1500rpm and sub-500rpm where it nearly dies before jumping back up to 1400 again. Might just be the ECU relearning things, but I'm also wondering if its something like the o2 sensor been fouled by running overly rich when the MAF was dying/dead.
Is it normal practice to recondition the MAF instead of putting in a new one? Seemed a bit odd for the main Subaru dealer in this area to be doing that, especially when its a warranty repair.
Is it normal practice to recondition the MAF instead of putting in a new one? Seemed a bit odd for the main Subaru dealer in this area to be doing that, especially when its a warranty repair.
Maybe it's particularly because it IS a warranty claim. I had trouble with a certain company beginning with L that sounds like . . . actually that's enough of that 
I'd ring the workshop tomorrow and ask them straight up why they aren't replacing it.
I've seen a few Scoobies that have weird and wonderful combinations of engines, heads, manifolds, gearboxes, electrics etc that you can't find in the manuals. It seems Subaru uses their customers to field tests stuff.
With that in mind, there is a remote possibility that your sensor is an orphan
I'd ring the workshop tomorrow and ask them straight up why they aren't replacing it.
I've seen a few Scoobies that have weird and wonderful combinations of engines, heads, manifolds, gearboxes, electrics etc that you can't find in the manuals. It seems Subaru uses their customers to field tests stuff.
With that in mind, there is a remote possibility that your sensor is an orphan
I'd check that they've installed the correct airflow meter and not one that was handy from a slightly different model. They may have also installed another faulty item, after all how many people have a spare working airflow meter sitting around but still feel the need to get one reconditioned?
The revs jumping around like that sounds like the idle control valve not getting things right - I'd check the fault codes again which may give you a better idea. There's always a knock-on effect in a situation like this.
Of course with a ten year old car some of the sensors and components could be a bit marginal and a load of unspent fuel and rough running could just be the final straw to one or two of them.
If it's under warranty make them replace everything until it's 100%
If you suspect the oil could be contaminated, get it replaced asap as you don't want the engine going pop to add to the problem!
The revs jumping around like that sounds like the idle control valve not getting things right - I'd check the fault codes again which may give you a better idea. There's always a knock-on effect in a situation like this.
Of course with a ten year old car some of the sensors and components could be a bit marginal and a load of unspent fuel and rough running could just be the final straw to one or two of them.
If it's under warranty make them replace everything until it's 100%
If you suspect the oil could be contaminated, get it replaced asap as you don't want the engine going pop to add to the problem!
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