Do i have a faulty Maf ???? MY98
01 January 2007, 07:38 PM
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Do i have a faulty Maf ???? MY98
MY98 Purple Sticker Maf 22680 AA280 A36-613-R80
slight pulsing in power delivery off boost.
The Revs increase/Rise slightly (250 Rpm) above 3.5k 4K ETc on Gear Change & then fall more slowly than normal.
Throttle cable is not to tight (checked)
Lambda has been swapped & it still does it.
Idle control valve has been cleaned & made no difference.
If the Idle control valve is unplugged it runs on 2 cylinders & hunts Etc, Plug back in & it stabilises.
Sometimes after a run (constant Speed, Motorway ETc) when stopped the idle would hunt for a while before stabilizing again
Also today whilst at a standstill the car became lumpy & would not rev over 1500 Rpm & when it reached 1500 rpm it died back down then backup to 1500 Etc, Happend for a few Mins then cleared
SO today, Unplugged Maf started car & it seemed to run fine, Drove off boost. Revs fell normally & no hunting ETc.
Ahh right MAf i thought, Plugged back in & the revs appeared to hang about & drop more slowly again.
Tried with maf unplugged again & it then started hunting slightly
DO i have an intermittent MAf fault ??
Are the Rev issues a sign of this ??
Ideas ?
Thanks
Dean
UPDATE
It would appear that when the car is warm & the Maf unplugged it runs fine, pulls Ok & idles !!!
Trouble is you can repeat this, I.e unplug the Maf again & it then runs crap, Idle all over the place, Missing.
So what can be drawn from this ??
Cheers
Dean
slight pulsing in power delivery off boost.
The Revs increase/Rise slightly (250 Rpm) above 3.5k 4K ETc on Gear Change & then fall more slowly than normal.
Throttle cable is not to tight (checked)
Lambda has been swapped & it still does it.
Idle control valve has been cleaned & made no difference.
If the Idle control valve is unplugged it runs on 2 cylinders & hunts Etc, Plug back in & it stabilises.
Sometimes after a run (constant Speed, Motorway ETc) when stopped the idle would hunt for a while before stabilizing again
Also today whilst at a standstill the car became lumpy & would not rev over 1500 Rpm & when it reached 1500 rpm it died back down then backup to 1500 Etc, Happend for a few Mins then cleared
SO today, Unplugged Maf started car & it seemed to run fine, Drove off boost. Revs fell normally & no hunting ETc.
Ahh right MAf i thought, Plugged back in & the revs appeared to hang about & drop more slowly again.
Tried with maf unplugged again & it then started hunting slightly
DO i have an intermittent MAf fault ??
Are the Rev issues a sign of this ??
Ideas ?
Thanks
Dean
UPDATE
It would appear that when the car is warm & the Maf unplugged it runs fine, pulls Ok & idles !!!
Trouble is you can repeat this, I.e unplug the Maf again & it then runs crap, Idle all over the place, Missing.
So what can be drawn from this ??
Cheers
Dean
01 January 2007, 08:54 PM
#2
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You're in a a similar position to mine. I've always had weird idle problems. Lately it's been the cold idle that has been playing up, warm idle's been fine. Last night I had the idle valve out again, and tried to investigate how it works by putting alternately boiling then cold water through its water pipes.
Now the idle is much worse.
I'm sure that buying a new idle valve and MAF from Subaru would solve it one way or the other. But that would be roughly £500-£600 worth of parts on a MY98 so out of the question.
Does seem odd that yours runs at all with the MAF disconnected, as mine won't even start with it unplugged. Although mine runs a Power FC so that may be part of it.
Now the idle is much worse.
I'm sure that buying a new idle valve and MAF from Subaru would solve it one way or the other. But that would be roughly £500-£600 worth of parts on a MY98 so out of the question.
Does seem odd that yours runs at all with the MAF disconnected, as mine won't even start with it unplugged. Although mine runs a Power FC so that may be part of it.
01 January 2007, 10:23 PM
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Originally Posted by silent running
You're in a a similar position to mine. I've always had weird idle problems. Lately it's been the cold idle that has been playing up, warm idle's been fine. Last night I had the idle valve out again, and tried to investigate how it works by putting alternately boiling then cold water through its water pipes.
Now the idle is much worse.
I'm sure that buying a new idle valve and MAF from Subaru would solve it one way or the other. But that would be roughly £500-£600 worth of parts on a MY98 so out of the question.
Does seem odd that yours runs at all with the MAF disconnected, as mine won't even start with it unplugged. Although mine runs a Power FC so that may be part of it.
Now the idle is much worse.
I'm sure that buying a new idle valve and MAF from Subaru would solve it one way or the other. But that would be roughly £500-£600 worth of parts on a MY98 so out of the question.
Does seem odd that yours runs at all with the MAF disconnected, as mine won't even start with it unplugged. Although mine runs a Power FC so that may be part of it.
I should of stuck with that Car !!!!
Dean
& no difference, So leaning towards the Idle control Valve now
02 January 2007, 08:54 PM
#6
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Well I can tell you from bitter first hand experience that trying to fix or even diagnose a knackered IACV is a bloody nightmare. And more to the point, a complete and utter waste of time. You can't see the air cut valve part at all, so there's no way of knowing whether it's working properly according to the water temperature going through the bottom. The main duty valve just goes back and forth and doesn't do much really. The electromagnet part in the top is quite easy to get tiny bits of metal swarf inside it, then as soon as you turn it on, it starts tearing chunks out of the spindle.
Your best bet is to get a replacement from a scrappies and just see if it works. Go on ebay, search for 'subaru breaking' and message every single seller on there to see if they've got one. Most of them have.
Your best bet is to get a replacement from a scrappies and just see if it works. Go on ebay, search for 'subaru breaking' and message every single seller on there to see if they've got one. Most of them have.
02 January 2007, 09:36 PM
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Originally Posted by silent running
Well I can tell you from bitter first hand experience that trying to fix or even diagnose a knackered IACV is a bloody nightmare. And more to the point, a complete and utter waste of time. You can't see the air cut valve part at all, so there's no way of knowing whether it's working properly according to the water temperature going through the bottom. The main duty valve just goes back and forth and doesn't do much really. The electromagnet part in the top is quite easy to get tiny bits of metal swarf inside it, then as soon as you turn it on, it starts tearing chunks out of the spindle.
Your best bet is to get a replacement from a scrappies and just see if it works. Go on ebay, search for 'subaru breaking' and message every single seller on there to see if they've got one. Most of them have.
Your best bet is to get a replacement from a scrappies and just see if it works. Go on ebay, search for 'subaru breaking' and message every single seller on there to see if they've got one. Most of them have.
I have been for a blast , Got it nice & hot , Left it ticking over for a good while & so far it has been Ok, Mine seems to start going haywire after about 20 Miles of driving & lots of stop start/ ticking over.
I think i will get a 2nd hand idle control valve , Fingers crossed.
Hope you get some luck with yours.
Dean
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02 January 2007, 10:22 PM
#8
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PM'd you back Dean. I've got a few suppliers of idle valves and have managed to get hold of one myself now. But I can forward an email from someone who's got one if you want. I think the key to it is that no amount of 'cleaning' of the idle valve will actually make any difference really. The only bit that you can get at to clean is not either of the bits that govern how the idle valve behaves.
Us 98 drivers with running problems have to stick together eh? What we really need is a Scoobynet 'pool' of brand new parts from Subaru that we could all borrow when needed to rule out potential problems. But for a brand new MY98 IACV, TPS, lambda/coolant/crank/cam/knock sensors, dump valve, purple/blue label MAF sensor, boost solenoid etc... you'd be spending well over a grand in parts from Subaru.
Us 98 drivers with running problems have to stick together eh? What we really need is a Scoobynet 'pool' of brand new parts from Subaru that we could all borrow when needed to rule out potential problems. But for a brand new MY98 IACV, TPS, lambda/coolant/crank/cam/knock sensors, dump valve, purple/blue label MAF sensor, boost solenoid etc... you'd be spending well over a grand in parts from Subaru.
Last edited by silent running; 02 January 2007 at 10:28 PM.
03 January 2007, 07:48 PM
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Originally Posted by silent running
PM'd you back Dean. I've got a few suppliers of idle valves and have managed to get hold of one myself now. But I can forward an email from someone who's got one if you want. I think the key to it is that no amount of 'cleaning' of the idle valve will actually make any difference really. The only bit that you can get at to clean is not either of the bits that govern how the idle valve behaves.
Us 98 drivers with running problems have to stick together eh? What we really need is a Scoobynet 'pool' of brand new parts from Subaru that we could all borrow when needed to rule out potential problems. But for a brand new MY98 IACV, TPS, lambda/coolant/crank/cam/knock sensors, dump valve, purple/blue label MAF sensor, boost solenoid etc... you'd be spending well over a grand in parts from Subaru.
Us 98 drivers with running problems have to stick together eh? What we really need is a Scoobynet 'pool' of brand new parts from Subaru that we could all borrow when needed to rule out potential problems. But for a brand new MY98 IACV, TPS, lambda/coolant/crank/cam/knock sensors, dump valve, purple/blue label MAF sensor, boost solenoid etc... you'd be spending well over a grand in parts from Subaru.
That would be a good idea, A pool of parts, Trouble is some bugger would borrow an item & never return it
As for my car
Well back to the Idle Valve Drawing Board !!
It's started again
Dean
06 January 2007, 01:47 PM
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Dean - just fitted the replacement idle valve last night. It took one cycle of messing about revving all over the place while it was warming up, then hit a rock solid idle once up to temperature. Started it this morning with 6 degrees of water temp and it does a good high idle, gradually lowering until it gets to a 750 rpm perfect idle at normal running temperature. Absolutely perfect idle and return to idle, so looks like the idle valve has sorted it.
08 January 2007, 04:31 PM
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Dean - just fitted the replacement idle valve last night. It took one cycle of messing about revving all over the place while it was warming up, then hit a rock solid idle once up to temperature. Started it this morning with 6 degrees of water temp and it does a good high idle, gradually lowering until it gets to a 750 rpm perfect idle at normal running temperature. Absolutely perfect idle and return to idle, so looks like the idle valve has sorted it.
Just fitted one to mine & so far
Well im not saying no more.
Glad yours seems to be cured, Lets hope it stays like that as they have a Bloody habit of coming back.
Dean
08 January 2007, 06:40 PM
#13
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Yeah keep everything crossed mate. Must say I'm loving the Scoob again now. Weird how just a crappy idle can totally spoil an otherwise great car. I seriously had thoughts of just flogging it if I couldn't get the idle right.
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