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Old 01-25-2004, 02:21 PM   #1
Scooby Newbie
Member#: 586
Join Date: Dec 1999
2002 WRX

Default Utech Question

I went to the my Subaru dealer a couple of days ago cause a sound coming from the left side of my 02 WRX. it sounds like ticking sound and it gets louder as you accelerate. Well He took for a test drive and he was saying that my car runs really rich. I noticed that A/f meter is allways stating rich under any driving condition. I have a stage 3 turboxs kit installed with stage three map. WHen the car is idling the meter should be bouncing back and forth right it should only show rich when then the car is under accelration correct? its always rich even if the pedal is pushed 10% down.

Well the CE light is also on and I have a obd scanner and i got a code p0131. THe subaru dealer told its the 02 sensor throwing the light on which makes the car run in open loop mode which is the reason why it is running rich. Does any one know if this is true?
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Old 01-25-2004, 03:16 PM   #2
Scooby Specialist
Member#: 33370
Join Date: Feb 2003
Location: Milwaukee, WI
2002 Impreza WRX
Blue now w/ 6 fun flavors


I dunno.. but how about you get a tune on your car and elminate improper fueling from potential issues and open up a lot of power.

PS.. at idle your AFR should float right around 14.7.. your utec can't change this for long as the fuel trims will adjust it back to that... your car as an O2 should'nt go into open loop fueling until something like 50% tps (from memory)
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Old 01-25-2004, 03:26 PM   #3
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Member#: 23676
Join Date: Aug 2002
Chapter/Region: NESIC
Location: de_dust and Orgrimar


FYI if your A/F meter is not a wideband meter, its useless and the readings it gives you are meaningless. Get a good wideband 02 sensor and a real A/F meter and do some tuning.

I do know that the off the shelf TXS maps are pig rich.
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Old 01-25-2004, 06:09 PM   #4
Scooby Specialist
Member#: 36528
Join Date: May 2003
Location: florida
2002 Impreza Wrx


FYI if your A/F meter is not a wideband meter, its useless and the readings it gives you are meaningless. Get a good wideband 02 sensor and a real A/F meter and do some tuning.
This is not true. Your a/f gauge should read fine as long as you're not running a lot of boost(more then say 9psi) or above 63% throttle. The reason the a/f ratio doesn't work above that is cause the ecu makes the engine runs richer under boost puting the stock o2 sensor out of it's "usable range". The o2 sensor can see that the car's running rich, it just can't tell how rich. The a/f gauge should be reading the correct reading at idle though.

I agree with the subaru tech. If the o2 sensor isn't working correctly, the a/f won't be normal because it's used directly to determine how much fuel the car gets. This would cause the ecu to work abnormally since it can't use the broken o2 sensor to do what it normally does(changing to closed loop or whatever). I'd first check the connections of the o2 sensor and make sure you didn't unplug it or anything. Other then that, getting a new o2 sensor would probably fix the problem.

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Old 01-25-2004, 09:32 PM   #5
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Member#: 5094
Join Date: Mar 2001
Location: Gaithersburg, MD, usa
11.96, 1.64, 115mph!



Most likely it is not a tuning issue but a component failure. I hate to state the obvious but you should perform a proper diagnosis on the front 02 sensor or the MAF sensor as one of these parts may have failed. You may also want to reset your ecu if you stalled the car at speed as this code can pop up under that conditon.

Good luck.
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