P1086 & P0031 after pulling/replacing motor. Halp?!

Discussion in 'Modifications And Maintenance' started by Krazylegz1485, Jul 9, 2017.

  1. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Greetings everybody. So, just had the motor out for some maintenance things this last week or so and drove it for the first time again this afternoon. While there were several small victories, of course it didn't go off without a hitch. I've got 2 CEL's now and would like some opinion sharing from the more experienced. Thanks ahead of time!

    03 WRX

    Issues: P1086 (TGV related) & P0031 (upstream 02 related).

    "Changes" made while motor was out:
    -replaced valve cover gaskets, all 4 cam seals and the crank seal, oil pressure sender, PCV valve, and oil cooler o-ring.
    -changed spark plugs
    -put in Tomei uel headers (re-used existing 02 sensor)
    -swapped motor & tranny mounts

    Upon googling both issues, I have a feeling that the P0031 code could be caused by some iffy wiring at the 02 sesnsor itself. I noticed at least one had some of the shielding rubber broken. I wrapped them with electrical tape before installation to prevent it from getting worse. Perhaps I should pull it back out either fix it or replace. Luckily it's pretty easy to access at the right front wheel well.

    Other pertinent information in this area would be that I'm totally catless. Did the resistor mod for the front, and the mechanical "spacer" mod for the rear. Apparently that might not affect this current issue, but just wanted to put it out there.

    For the P1086, I'm not sure. Do the TGV sensors just randomly go bad? I didn't remove anything in this area that I'm aware of. Seems like everything is plugged back in. Only sensor that I messed with was the cam position sensor for the driver side intake came (on the top of that head) while replacing valve cover gaskets and cam seals. Ideally I'll do TGV deletes in the future but that's a little out of the budget for the time being (thinking I'd like to do Aluminati's).

    Much appreciation to anybody offering assistance!
     
    Last edited: Jul 9, 2017
  2. tangledupinblu
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    tangledupinblu Event Coordinator Staff Member

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    I am wondering if the new headers are causing issues with the O2 sensor?
     
  3. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    That's definitely a possibility, of course. The CEL came on immediately when I started the car, so in my head I was leaning towards a sensor failure I guess. If it's basically a temp sensor would it take "longer" to calculate an issue?
     
  4. jmyhre05
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    jmyhre05 Well-Known Member

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    Check the o2 sensor itself and see if you bumped it when pulling or installing the engine. Look at the sensor end and the wires to the sensor. Would most likely just need a new sensor.

    The tgv one same thing. Just check the sensor and the connection. If they look good may be time to just delete them.
     
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  5. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Thanks, Jesse. Really looking forward to the day this thing gets over to your place for a tune. TGV deletes, injectors, more fuel, and a tune is definitely next on the menu.
     
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  6. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Just pulled the 02 sensor out because I couldn't go to sleep tonight without at least checking. Somehow the white wire right up next to the connector got smashed at some point (probably while laying on the floor while attached to the old exhaust) and had a pretty good amount of separated wires.

    Also ohm'd out the black wires and didn't even get a reading. So unwrapped my electrical tape wrap and found another almost complete break or two.

    Guess I'll be checking into a new sensor then. At least I feel like I've got a definitive answer for this one.
     
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  7. JasonoJordan
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    JasonoJordan Well-Known Member

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    Is the break far enough back to solder and heat shrink?
     
  8. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    That's the best part. Both of them are about a 1/4" from either end. Don't think there's enough room to cut, strip, & splice. Probably gonna give it a shot anyways, since I've got nothing to lose at this point.
     
  9. JasonoJordan
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    JasonoJordan Well-Known Member

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    Rockauto had some pretty good prices on O2 sensors last time I looked.
     
  10. joebush44
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    joebush44 Well-Known Member

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    If the sensor is in when pulling or dropping the motor in, it's fairly easy to bang/scrape it against the frame rail. Or so I've been told :unsure:
     
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  11. Krazylegz1485
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    It was in when pulled, and I'm assuming that had a little to do with it. I actually had to "adjust" the sheet metal down there to get it into the hole in the headers once the motor was back in.
     
  12. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Struck out on a quick search for a used sensor locally so scored a new one on eBay for $71 shipped. Hopefully will be here by this weekend.

    So, assuming that takes care of my O2 light, anybody got that magic solution for the tgv one?
     
  13. jmyhre05
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    jmyhre05 Well-Known Member

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    Just so you know, aftermarket sensors tend to have a much higher failure rate. Even the store bought denso ones. We only install the oem Subaru boxed ones for this reason. Less headaches.
     
  14. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    I read that on a handful of forum posts. The one I got is Denso brand.

    http://www.ebay.com/itm/142440014869

    *Just reread your part about the Denso ones. Dammit. Isn't Denso the OEM ones?
     
  15. jmyhre05
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    Denso does make the oem ones but for whatever reason we see a higher failure rate with the denso ones over the oem ones. Call me crazy, can't explain it but just what we have seen.
     
  16. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Any idea what Subaru charges for the OEM-oem sensors? Mine came today and the wiring is significantly shorter. Haven't tried it in the car yet but I'm pretty sure I can tell by looking that it's gonna be too short. Sure I can just extend all the wires, but trying to weigh my options here.

    Thanks!
     
  17. jmyhre05
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    $220-$250 retail. Mnsubaru has a discount
     
  18. joebush44
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  19. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Mine calls for 234-9011. Not sure what the differences are. I also made mine "fit" by just rerouting the car side harness.

    Cool thing now is my 0031 code went away and was replaced with an 1130 (open circuit). So I got that going for me, which is nice.
     
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  20. joebush44
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    Oops - the one I linked to is for GD STi. I realize now that you already got the Denso sensor...odd that the harness was too short. Bummer that you have a different code now. I've had good luck using the "non-oem" Denso sensors, but your car seems like it might be a bit more picky.
     
  21. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Yeah, I'm not really sure what do to now. I've got a basic scan tool and can read and clear codes, but haven't officially "reset" the ecm. That said, I did find the fuse that applies to the O2 sensor circuit and pulled that. Of course it fell underneath the battery as I pulled it out, so have no choice but to remove the battery to get to it, so guess I'll get my hard reset at the same time.

    If that doesn't work, what else? An "open" circuit tells me that the sensor must be dead out of the box, right? Previous code was just "low" which means it either was reading wrong because of the header change or possibly due to the damaged wires causing a big enough change in resistance or something.

    Would love to go drop $200 at Subaru for an actual oem one, but that's gonna have to wait about a month until after we close on the house.
     
  22. joebush44
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  23. jmyhre05
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    Also if your ecu sees that problem with the o2 sensor long enough, it will cut power to the o2 sensor from the ecu. That could be the "open" circuit problem. Try hard resetting it, if it persists then you got another issue.
     
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  24. tangledupinblu
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    tangledupinblu Event Coordinator Staff Member

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    "Don't argue with me on this one sonny...go get the OEM one"-Unabomber

    lol
     
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  25. Krazylegz1485
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    Hahahaha. Saw that one this morning, too.
     
  26. joebush44
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    Basically lol
     
  27. Krazylegz1485
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    Pulled the battery to get my damn fuse back from the depths. Fuse was fine, put it back in. Reconnected battery and checked the codes right away. TGV code was still there but O2 sensor one was gone. I was stoked. Took it for a trip "around the block" to get everything warmed up and see what happens. Drove fine (still), nothing exciting either way. Got back, read the codes, O2 sensor code came back (1130).

    F'k you, car...
     
  28. pillboy
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    pillboy Well-Known Member

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    Cars can tell when you are stoked. Never let on. Always expect the worst from the car and you will never be disappointed.
     
  29. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Kinda the opposite, too. When you're sick of them and tell them out loud that they'll be replaced soon if they don't shape up, sh!t just magically starts working right... Maybe I should try some reverse psychology on her.

    By the way, anybody know how to tell wire colors in the Subaru FSM? Looking up the troubleshooting procedure for the specific codes and everything is just black with no color descriptors.
     
  30. Krazylegz1485
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    Copied and pasted here to keep it in this thread.

    Assuming #2 is the big yellow/red wire, I had 12.16 with the key on.

    1 has 2.85, 2 has 12.16, 3 & 4 both have 3.83.

    Commence head into wall...:banghead:
     
  31. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Small victories! That's all we need, right?!

    Bought a used tgv sensor on eBay for $30 and it showed up today. Swapped out the old one with it and disconnected the battery again while I was right there.

    Poof! One code down.

    On the O2 sensor side of the game, I feel like I at least made some mental progress. I'm still getting the "open" code whenever the new one is hooked up. So I left that one in the exhaust, basically just to plug the hole, and connected the old one to the car and just set it on the intercooler (out of the way). It then switched codes back to the "low" one.

    I guess this is more of an opinion than fact, but that kinda tells me that it wasn't the aftermarket headers that were responsible for the code to begin with (like maybe they caused it to read incorrectly or something) and instead it's still just a bad sensor.

    So, much to probably everybody's dismay, I bought another one on eBay. This one is an actual oem one out of compatible year WRX. So yes, it's used, but it comes with a 100% satisfaction guarantee or my money back no questions if it doesn't work. So yeah, I'm playing with fire again but at least I'm only out a little time in the long run.

    And absolute worst case scenario it sounds like we're gonna be more than clear of overall down payment and closing costs for the house, so if I have to I'll just go pony up at the dealer and get a new one. (Still hesitant since I don't know if that's the for sure problem).
     
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  32. 02subbieRS
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    02subbieRS Well-Known Member

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    FWIW, I bought an identical Denso O2 for mine from amazon for $99 shipped. Same numbers and everything.
     
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  33. Krazylegz1485
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    That's pretty much what I got on eBay the first time. Brand new in the box, which even had a Subaru logo on it. The sensor was identical as far as the Denso part numbers and everything. Only thing the new one didn't have was the "22641 AA042" Subaru part number. That and the wiring harness was almost a foot shorter.
     
  34. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    Two small victories make one big one!

    Second sensor got delivered today. Got off work a little early today which was perfect as well. Pulled the battery cable, jacked the car up, swapped out the "new" sensor for the new to me used one. Reassemble, connect battery, fire.

    Whammy!

    [​IMG]

    I'd say it's Christmas in July here but I feel like that would require a bunch of lights on, and mine are all out now. Which is quite alright by me. Even mixed a celebratory drink in my color changing Subaru cup. I mean, it's at least 5 o'clock in Venezuela...
     
  35. Cotts612
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    Cotts612 Active Member

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    Now go drive like a bat out of hell!
     
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  36. Krazylegz1485
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    Planning to go get myself embarrassed next weekend at Powercruise.
     
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  37. tangledupinblu
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    Are you putting on the tip?
     
  38. Krazylegz1485
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    Krazylegz1485 Well-Known Member

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    To be honest with you, I've been debating. Chances are it would be received negatively by the masses that can't take a joke. And I've never heard it outside of the car, so I'm not even personally sure of how loud and obnoxious it actually is. As much fun as it would be, I don't wanna be "that guy" there. I don't know.

    I could say f the hatters and just roll with it...
     
  39. Krazylegz1485
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    I just re-read this and I'm now assuming you're correlating the embarrassment with having the tip on. I was speaking strictly from a speed standpoint, but I can see either one being the cause.
     

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