P0171 and APv3 Questions
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This is a discussion on P0171 and APv3 Questions within the Tuning: Electronic Engine Management forums, part of the Tech & Modifying & General Repairs category; I recently bought a 03 WRX, 89k on it, had a Perrin Intake, Invidia (Catless) Downpipe, Cobb CBE, and what ...

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    P0171 and APv3 Questions

    I recently bought a 03 WRX, 89k on it, had a Perrin Intake, Invidia (Catless) Downpipe, Cobb CBE, and what appeared to be an eBay header on it considering it had a nice crack in one of the welds. I got a decent deal on the car knowing it needed some work. I knew it was throwing the P0171 code, and assumed it was because of the exhaust leak about 3-4" from the O2 Sensor. Last week I replaced the header w/ a Tomei UE, and am currently running Cobb's OTS Stage 2 91 map (actually running 93 octane in the car, but I figured the 91 map would run a little more rich). After replacing the header I reset the ECU and the code came back after about 20 miles. I've since checked all vacuum lines, bench tested the front O2 sensor, and cleaned the injectors. I reset the ECU once more and the code stayed away for 3 days, but now it's back. A/F ratio at WOT is showing anywhere from 12.1-12.4 @ WOT (I know the factory O2s isn't very accurate below 12.5), between 14.3 and 14.9 when cruising, and as high as 24 when engine braking. My question is should I be looking more for faults with the car or could this simply be a result of the map I'm currently running?
    All help is greatly appreciated, I've searched the forum pretty hard, but it seems everything to do with the P0171 is about fixing issues with the car. As I haven't found anything out of the ordinary, I'm starting to think that it may just be the tune.

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    He simply abides. SD_GR's Avatar
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    Correct me, but I don't think your map supports headers. Does it? Does it support the intake?

    If no, replace either the headers and/or intake or the map.

    If yes, troubleshoot a PO171 as usual (search if needed) and start by cleaning the MAF and air filter, checking the FPR connection etc..
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    Sammich Makin' Pwincess wrxtreme06's Avatar
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    The ots map isn't designed for the mods you have

    Either get the stock header and stay with the stage 2 tune (for the proper gas) or keep the header and get a custom tune


    Edit: jk. SD took the words out of mouth lol

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    He simply abides. SD_GR's Avatar
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    Quote Originally Posted by wrxtreme06 View Post
    The ots map isn't designed for the mods you have

    Either get the stock header and stay with the stage 2 tune (for the proper gas) or keep the header and get a custom tune


    Edit: jk. SD took the words out of mouth lol
    Yours is the direct, informed answer.

    You know, I'd be tempted to fit the stock intake as well as header. I doubt the intake is doing much other than at least contributing to PO171.
    WRX Info Links, Courtesy TheJ
    Man is a brute.... If you're cruel to him, he respects and fears you. If you're kind to him, he plucks your eyes out. Alexis Zorbas
    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
    DISCLAIMER: Opinions expressed are the author's alone and are inherently worthless.

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    Thanks guys, that pretty much validates what I was thinking. The Cobb OTS maps only support Cobb and AEM intakes and neither support aftermarket headers. And going up, Stage 3 only supports aftermarket turbos (VF34/16G). I was just trying to get a good basemap to work off of, and my thought was that the 91 map would provide slightly more fuel than the 93. I'll try to get a datalog with each tomorrow and see where I can go from there. I'm thinking it's fairly close now, car seems to run pretty good. Do you think I can get by just doing a little MAF scaling?

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    He simply abides. SD_GR's Avatar
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    I'm skeptical. However see post 12 here:
    Need a logging file
    WRX Info Links, Courtesy TheJ
    Man is a brute.... If you're cruel to him, he respects and fears you. If you're kind to him, he plucks your eyes out. Alexis Zorbas
    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
    DISCLAIMER: Opinions expressed are the author's alone and are inherently worthless.

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