p0171 power loss and ocasionally evap code
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This is a discussion on p0171 power loss and ocasionally evap code within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; The past few weeks i have been getting the p0171 code and experiencing some significant power loss. I have an ...

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    p0171 power loss and ocasionally evap code

    The past few weeks i have been getting the p0171 code and experiencing some significant power loss.

    I have an 02 wrx wagon w/ short ram intake on it.

    i started getting the code around when i changed to the short ram intake, at the same time i had some work done to my exhaust (new sensors and cat)

    however the problem seems to be worse than before

    I just replaced the fuel filter, and ran some injector cleaner threw...no help
    I changed the pluggs
    I have checked multiple times for a leak after the maf in the intake system, cant find anything.

    Not sure where to go from here???

    Possibly bad maf?? i have no way to check and i dont want to shell out 100+ for a new one

    i was also thinking bad fuel pump because of the ocasional evap code?

    anybody have any ideas or where to check next?

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    He simply abides. SD_GR's Avatar
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    PO171: Fit the correct intake, clean the MAF, check for vacuum or boost leaks, check the connection to the fuel pressure regulator, and reset the ECU.

    Evap code: Since there is no code number I can't comment.

    Search PO171 and the variation P0171 for more details (sorry on the road right now).
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    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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    Sry p1443 is the other code, however I'm not getting that one consistantly

    I cleaned the maf well

    I can't find any vacuum or boost leaks however if you have a better way to check I will try it

    I have reset the ecu multiple times

    I bought the intake online and it fits perfectly so as far as I know it is correct

    I don't know how to check fuel pressure regulator I will look it up and post back

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    Quote Originally Posted by jzito View Post
    I bought the intake online and it fits perfectly so as far as I know it is correct
    Imitation or unauthorized parts are not correct.

    Only Subaru parts intended for the specific model are correct.

    If you cannot find another cause for the P0171 I would suspect the intake.
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    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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    i will swap out for stock air box tonight and post back on the results

    if it is the case that the intake is bad
    i understand spt products are prefferable
    but would perrin or companies like it be considdered unauthorised?

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    Quote Originally Posted by jzito View Post
    i will swap out for stock air box tonight and post back on the results

    if it is the case that the intake is bad
    i understand spt products are prefferable
    but would perrin or companies like it be considdered unauthorised?
    If it's not made by Subaru, it's not made by Subaru.

    There are intakes that are not authentic Subaru parts that may or will work. I see no need for them generally though.

    Is your MAF sensor installed with the harness facing forward?

    When you reinstall the correct intake make sure the filter top housing is seated well in the tabs.

    Check again for other vacuum or boost leaks and check again the fuel pressure reg. connection.
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    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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    Oh, about that evap code. If it is not associated with refueling (so a loose gas cap) then check the harness that goes to the canister. It may take a little contorting to reach but sometimes the wires are loose, or damaged, and that'd explain an intermittent fault. Next is the canister itself but I'm betting the wiring, if anything. Pls. search with the CEL code and you will see threads with more info.

    Pls. post back re: 171 code, I'm optimistic you'll sort it.
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    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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    Good call on the intake, i have 50 miles on it without the cel coming back.
    Before it would come back on in 10,
    hopefully it will stay that way

    When I get a chance I will take a look at the wiring and let you know.

    So I learned my lesson and I wont buy anything unless its from subaru.

    If I do get an spt intake, is it still possible for me to have problems?

  10. #9
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    Quote Originally Posted by jzito View Post
    Good call on the intake, i have 50 miles on it without the cel coming back.
    Before it would come back on in 10,
    hopefully it will stay that way
    Fantastic. If it does happen to come back, check again that the cap on the filter is in the tabs correctly and suspect again that the MAF has residual dirt. Sometimes that happens but rarely. From what you have said though you are on the right path.

    When I get a chance I will take a look at the wiring and let you know.
    OK. Have a look at the various threads for the evap problem meanwhile, as you can't fix it or even troubleshoot it while it's apparently working.

    So I learned my lesson and I wont buy anything unless its from subaru.
    I have a confession to make: I am almost certain I hold a minority view on these issues here, and can guarantee many, many people will disagree. Here's my view: Subaru are best at making Subarus since they've made more Subarus than anyone else, including probably all the world's specialists, tuners, etc. combined. They've also put their money where their mouth is because they provide each and every car with a warranty -- so they know it works at least well enough to be financially viable for them.

    Are there parts that are stronger, lighter, more effective, etc. for a Subaru that are not made by Subaru? Sure. But it is also very likely that the average person will come in contact with junk too. The easiest way to sort what's what is to just ignore it all and stick to stock components.

    Now, many people consider themselves enthusiasts and like to modify their cars. Great. It's pay to play though, and there are no guarantees generally.

    With the intake in particular, since there is very little benefit for the average owner, I tend to just generalize and say "forget it" and feel quite safe in doing so.

    If I do get an spt intake, is it still possible for me to have problems?
    Yes.

    The SPT parts are sold by authorized Subaru channels but -- last I checked -- even they do not maintain the new vehicle warranty. This issue becomes a moot point generally, as the SPT parts come with a separate SPT warranty and Subaru are confident enough to know they can make $$ while selling them and the cars will still run.

    My concern with any intake in general is whether air flow patterns are maintained, whether correct air metering is allowed, and whether filtration is optimal.

    The SPT part achieves the first two goals. I doubt it is as good at filtering air as the stock intake though, just because it uses a different filter. I have never seen data from the SPT part. This makes my guess, that it doesn't filter as well as the stock part, just as useless (repeat: useless) as the guess of those that say it works great. Neither side have data...

    It's a good part, it fits correctly, and it looks nice too. You can save some money by shopping very carefully if you insist on an intake, as there are at least two more non-SPT, non-Subaru parts that will not give you the CEL you got (at least not until the MAF gets really dirty due to an open filter design, if/when that happens). I don't recall their names though (I use the stock part and don't care about looks/sound etc).

    Enjoy the car.
    SD
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    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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