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Old 16 Sep 2007, 09:12 PM   #1 (permalink)
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MAF sensor

Hi Folks

I have a MY06 Impreza and in the last week I have uprated the turbo to a VF34 and a sports cat downpipe. Car has been mapped and is putting out 340bhp and 390 ft Lbs torque. Took the car on a track day and the next day I went to drive teh car, it is running like a bag of spanners. It has been suggested that it maybe the MAF sensor. Where is this and how to I get it out to clean it. What do I clean it with?

Any help appreciated!
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Old 16 Sep 2007, 10:09 PM   #2 (permalink)
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Would be amazed if its maf sensor that early,thought later cars had got waay better mafs,ive got a my00 classic with the tempremental ones an even that lasted till 45,000mile arent you getting cel coming on-may be o2sensor related if its been disturbed though not 100% sure about the set up on later cars regarding how many sensors there are on the exhaust.

Would take it in and see what subaru say-a mates 06sti`s already had engine work under warranty at low miles.
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Old 16 Sep 2007, 10:11 PM   #3 (permalink)
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Need more info about what its doing/not doing to be fair.
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Old 16 Sep 2007, 10:19 PM   #4 (permalink)
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Need more info about what its doing/not doing to be fair.
When I pull off from a dead stop, the car reluctanly moves off and when I put the throttle down, teh car doesn't want to go, but it eventaully does. It does this right through the rev range. Its not violent, jsut little a delayed response and teh car isn't running on full boost it seems. I can't take into get warranty work cause Its been remapped and the TD04 has been taken out!
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Old 16 Sep 2007, 10:35 PM   #5 (permalink)
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Mates were remapped an got away with it however is pally with the dealers,if its boost related have ya checked that it aint just a split vac pipe /induction hose loose(though realise these are fairly new)would say it sounds like limp mode however cel would be on and wouldnt reach full boost-waay weird-car aint bin overfilled with oil has it clutching at straws could be a sticky boost solenoid or "possibly" weak actuator/dumpvalve spring though would hear it losing pressure through the dv .(by the way unlucky if you`ve sold the old turbo regarding warranty)

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Old 17 Sep 2007, 11:40 AM   #6 (permalink)
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could possibly the maf, the uprated turbo has been known to wipe them out in older cars (classics) when combined with front mounts, so maybe just doing the turbo and the extra airflow has done it maybe.
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Old 17 Sep 2007, 08:52 PM   #7 (permalink)
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i`d be pissed off though if its the maf if it is a lowish mileage 06 mate.
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Old 17 Sep 2007, 09:39 PM   #8 (permalink)
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i`d be pissed off though if its the maf if it is a lowish mileage 06 mate.

yeah, tis known to be a problem with higher airflows though, tis one of the reasons i had to go autronics with mine
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Old 21 Sep 2007, 08:38 AM   #9 (permalink)
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I have more info on my running issues.

I took the car back to the mapper and he has noted that the ECU is detecting knock at low revs (1.5 - 2.8ish), and therefore retarding the ignition to protect the engine. The condition is stored by the ECU so the next time the knock occurs, the ECU pulls it back even further, therefore causing an accumulative effect. Resetting the ECU clears this and gets me about 30 miles before it starts to retard ignition again. The weird thing is that the mappers own knock-sensor (used with headphones) is not detecting the knock! Weird. He then suggested that it is perhaps a damaged ring land. I'd have thought that this ought to cause smoking and should also be detected right through the rev range.

He plugged his daignostic system into the car and did not have any readings regarding a dodgy MAF or otherwise.

I still have the standard bits, minus the DP, need to see if I can find that as I never got it back from the custom builders when they fitted the sports cat.

So, gentlemen, any thoughts on that?

Thanks
J
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Old 21 Sep 2007, 11:24 AM   #10 (permalink)
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first guess would be a dodge nock sensor.

if the mapper is happy there isn't any but the sensors saying there is then could be that
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Old 22 Sep 2007, 08:33 AM   #11 (permalink)
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first guess would be a dodge nock sensor.

if the mapper is happy there isn't any but the sensors saying there is then could be that
It's the ECU that's detecting the knock though, which would mean a dodgy ECU. What are the chances of that happening?
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Old 22 Sep 2007, 02:40 PM   #12 (permalink)
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It's the ECU that's detecting the knock though, which would mean a dodgy ECU. What are the chances of that happening?
Well of course the ECU takes its data from the sensor; DOH! Yeah, I am going to change the plugs and the KS and hopefully that will rectify it. If not, I'm looking at piston damage as I can't see any other options.
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Old 01 Oct 2007, 05:06 PM   #13 (permalink)
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Sounds like i have the same problem.

I have an 02 GX Sport and my car is doing the same thing as you describe i.e. at idle it won't pull away very cleanly but once its reving it is OK. I keep getting the orange CEL coming on, Subaru tell me its a IAC problem.

The light will go off for a while then come back on again! Above 3,000 rpm the engine is fine, its just when driving slowly through town its rubbish.

I have taken the IAC off and cleaned it with carb cleaner & that seems to have made no difference. It did not look too dirty to start off with. I did wonder about the MAF too. I am not 100% sure where to find it. I would like to remove it and clean it & see if the problem is resoved. If it is then i will buy a new one.

Last edited by Terrydlm; 01 Oct 2007 at 06:49 PM.
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Old 28 Dec 2007, 10:32 PM   #14 (permalink)
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Hey dude

I have the same problem....


DID ANYONE FIND A FIX???


PLEASE REPLY THANKS!
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Old 02 Jan 2008, 08:51 AM   #15 (permalink)
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im guessing it was a sensor issue since no posts after it was susgested
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