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Old 06-25-2011, 03:55 PM   #1
jaegmeister
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Default unplugged my maf sensor - now car runs better

I've been troubleshooting my 97 outback sport's intermittent rough running . quick question: if my maf is the cause, and I unplug it, how should my car run ? Ive tried this, and it runs a lot better, but not perfect.
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Old 06-25-2011, 04:46 PM   #2
a1killer
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Normaly if you unplug your maf sensor from your ecu it should run a tad better to rougher depending on tons of things. But id suggest you try and find another maf unit and see if that fixes your problem if not there could be something wrong with your fire or fuel mixture or your ecu settings.
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Old 06-25-2011, 05:14 PM   #3
RaceFaceXC
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When the maf is unplugged the ecu ignores the maf, o2 sensors and probably some other data streams. Hard to say what the problem is if all you tell us is that it runs "better". I wouldn't suggest driving it like that without a way to monitor afr's. Anything on the engine changed from stock. The only bad maf I knew of caused starting problems and made the car almost impossible to drive.
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Old 06-25-2011, 05:30 PM   #4
cdwahl
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Default is the MAF dirty?

I would start by cleaning it with a spray...
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Old 06-25-2011, 06:38 PM   #5
jaegmeister
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Quote:
Originally Posted by RaceFaceXC View Post
When the maf is unplugged the ecu ignores the maf, o2 sensors and probably some other data streams. Hard to say what the problem is if all you tell us is that it runs "better". I wouldn't suggest driving it like that without a way to monitor afr's. Anything on the engine changed from stock. The only bad maf I knew of caused starting problems and made the car almost impossible to drive.
Yeah, it has been pretty impossible to drive when it is throwing a fit, and won't want to start. then the next minute it runs perfect... And I've cleaned the maf. So by unplugging it, I may just be masking some other problem?
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Old 06-26-2011, 09:19 AM   #6
RaceFaceXC
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Yes. It could be anything that is disabled when the maf is unplugged. I know I messed up my punctuation in my first post. I meant to ask if there has ben any changes to the car from stock, not make a statement with a period after. And when you say its intermittent, do you mean randomly or does it seem to run ok when the engine us cold and then get crappy after it warms up?

MOAR INFO, pls
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Old 06-26-2011, 12:10 PM   #7
joebobanaught
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If you have a dirty maf, bad maf, or if there's some vacuum leaks, unplugging the maf will give better results because the data is incorrect if plugged in. Try to find a nearby member who will let you swap mafs and see how your car runs with a "new" maf.
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Old 06-26-2011, 03:37 PM   #8
jaegmeister
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The car is all stock. And the problem seems to be 100% random except possibly more frequent when it rains. UPDATE: I swapped out the maf with a remanufactured one and it started , ran, revved perfect. I couldnt drive the car as it was the store's and they just let me try it in the parking lot. As doon as i plugged mine back in, it was back to running like crap. So, hopefully problem solved.
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Old 06-27-2011, 09:35 PM   #9
jaegmeister
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UPDATE: New maf installed ($40 for two sensors!!) Car is back to normal. I had a couple threads pertaining to this problem, with different questions, so thanks to everyone that helped.
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