Looking for some direction on diagnosis
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This is a discussion on Looking for some direction on diagnosis within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I have a 2002 WRX. Relevant mods are: Grimmspeed uppipe Invidia catless downpipe NGK2667 (one-step colder) plugs Walbro 255 fuel ...

  1. #1
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    Looking for some direction on diagnosis

    I have a 2002 WRX. Relevant mods are:

    Grimmspeed uppipe
    Invidia catless downpipe
    NGK2667 (one-step colder) plugs
    Walbro 255 fuel pump

    I had been running a Cobb OTS stage 2 tune for a while after the downpipe, but decided to move up to an e-tune. In the process of tuning and logging, the tuner has told me that I am dealing with a lot of "misfire". The DAM is constantly dropping to 8 or 9 and moving around 8-12 and sometimes up to 15. There are no CELs.

    I installed the plugs and fuel pump this past weekend right before flashing the preliminary e-tune map. I checked some previous logs from my old plugs that I hadn't reviewed yet and noticed the same issue, so I've ruled out the plugs being the problem. I also ruled out the pump obviously, and I replaced the fuel filter a week ago. Things I'm going to check now:

    Compression and leakdown tests
    MAF
    Vacuum/boost leak test
    PCV replacement
    FPR hose
    Coil packs (how should I test these?)
    Rattling parts setting off knock sensor
    Cam timing and sensor cleaning
    Clean grounds

    Here is a log with default params from before the plugs and pump (with Cobb stage 2 OTS tune) with a WOT run somewhere in there:
    https://docs.google.com/spreadsheet/...1OXFnTEE#gid=0

    Here are some logs I sent to the tuner:
    Around the block log: https://docs.google.com/spreadsheet/...2QWVia2c#gid=0
    Idle log: https://docs.google.com/spreadsheet/...WUVJIV2c#gid=0
    WOT log: https://docs.google.com/spreadsheet/...4TjRDTVE#gid=0

    These are not the default parameters, so let me know if I should do another log with other params.

    Anyone have any other ideas or indications of specific things I could look for?
    Last edited by jonno; 01-21-2013 at 01:28 PM.

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  3. #2
    Master Baiter EJ257's Avatar
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    When you checked the plug gap, what did you get?
    2005 WRX STi (Mods | Virtual Dyno)

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  4. #3
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    Apr 2011
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    The new plugs were pre-gapped to 0.030. I did not check them, as they are iridiums and everything I read said to not touch them and to trust the pre-gapping.

    Old plugs I didn't check, but I saved them and could check. However, seeing the problem in previous logs with previous plugs still in makes me think that the plugs are not the issue, unless something else is causing them to malfunction.

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