Another misfire thread
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This is a discussion on Another misfire thread within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I bought an '02 Bugeye with 130k about a month ago. I replaced the timing belt, tensioner, idlers, and water ...

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    Another misfire thread

    I bought an '02 Bugeye with 130k about a month ago. I replaced the timing belt, tensioner, idlers, and water pump first. then I replaced the plugs with the OEM NGK's. The car runs perfect and has tons of power. It does get misfire codes though, and I'm wondering why. My big question right now is- could I be running the wrong fuel and would it cause misfires? I'm using 93 octane. I wonder if I should try 91. I have no way to find out what the previous owner used. I'm going to check the cam timing but as good as it runs I can't imagine one of the cams being off a tooth. Also, I turned the engine around by hand half a dozen times before reassembly and all marks were perfect. Still need to check grounds and air leaks, and I haven't replaced the fuel filter yet, but I will soon. Thanks for playing.

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    I already did, about 3 times. As you can see, I'm working my way down the list. Waiting for injector cleaner to work. I'm only pulling about 15 PSI of vacuum, (checked where the turbo meter hooks up) but it is steady. Can't forget your basics, no matter how complicated the engine may be. I forgot to say in my original post, I also cleaned my MAF sensor.

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    Were the misfires happening before you did the timing belt (and misc other parts) install?

    What was the plug gap? You verified this or are judging by what was indicated on the box (I've seen them be "off")?
    Seafoam / Top-End cleaner?
    You've tested for leaks? Pressure or smoke.
    You've cleaned the MAF (not just the IAT sensor)?
    Grounds look solid?
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    I set the gap to .028 and got it perfect. I'm having a hard time remembering if the codes fired before I put the timing belt on and I know that is important. I don't think they did. I guess I should remove the covers again and double check cam timing. I'm getting misfire codes on cyl's 1,2,and 3 so the problem probably is not related to one bank. I don't know the cylinder numbers on this confounded boxer engine yet. I need to get a book as this thing is becoming my new hobby!
    Are the grounds the strap type connections at the front of the intake? I'm assuming the MAF is the sensor in the air tube that comes out with 2 screws. 2 metal legs with a brown oval blob on the end of them.
    Last edited by zoe60; 08-19-2012 at 07:38 AM.

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    I see what you mean about the MAF. I really hadn't sprayed it at all. Thanks for your help, I have to leave now, but I'll be back on later.

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    Quote Originally Posted by zoe60
    I set the gap to .028 and got it perfect. I'm having a hard time remembering if the codes fired before I put the timing belt on and I know that is important. I don't think they did. I guess I should remove the covers again and double check cam timing. I'm getting misfire codes on cyl's 1,2,and 3 so the problem probably is not related to one bank. I don't know the cylinder numbers on this confounded boxer engine yet. I need to get a book as this thing is becoming my new hobby!
    Are the grounds the strap type connections at the front of the intake? I'm assuming the MAF is the sensor in the air tube that comes out with 2 screws. 2 metal legs with a brown oval blob on the end of them.
    The bulb is the IAT sensor. The MAF is inside the tube:
    $5 and 5 minutes to a better running car :)
    2005 WRX STi (Mods | Virtual Dyno)

    Resident Tuner @ WTF Tuning, LLC

    "Never trust anything that bleeds for a week and lives ..."

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    I cleaned the MAF this time. Won't make that mistake again. Drove about a mile and the CEL went out! I gotta say, thanks for your help, you know these cars pretty darn well. Keeping my fingers crossed that it stays out but right now things are going great. Runs better too!

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