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Check Engine: Misfire

Posted by Justin_97DSM, Jun 23, 2019

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  1. Justin_97DSM

    Justin_97DSM Probationary Member

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    Joined Jun 19, 2019
    Akron, Ohio
    I bought my Eagle Talon two weeks ago, knowing it had misfire issues from the previous owner. I want to see if anyone had experienced this and/or knew what to do. When driving it, it doesn't misfire, but it posts all 4 cylinders misfiring. I'll post the codes. Thank you.
     

    Attached Files:

  2. Brembo

    Brembo Proven Member

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    Clifton, New Jersey
    The way I see it is that all cylinders are sharing something that causes it to set misfires codes. I would check first fuel trim, cranks/cam signals. Depending what I would find would dictate the direction to go. Second I would pull the plugs and measure the gap and do a visual inspection. Third I would do is check compression while I have the plugs out, to make sure we don't have some issues with mechanical timing. Forth I would grab a bear and start analyzing the data that I have on my hands.
     

    Street Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  3. dustyboner

    dustyboner DSM Wiseman

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    :confused: :confused:
    OMG

    HlhRL7I.gif

    ROFLROFLROFLROFLROFLROFLROFLROFLROFLROFLROFLROFLROFL
     
  4. Brembo

    Brembo Proven Member

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    Hahaha made my day. Thank you
     

    Street Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  5. dustyboner

    dustyboner DSM Wiseman

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    abq, New Mexico
    bear.jpg :thumb:


    =================================================================================

    to get back on topic

    if the check engine light is flashing when it missfires, its probably the ignition system.

    upload_2019-6-23_11-42-47.png
    upload_2019-6-23_11-43-29.png

    upload_2019-6-23_11-38-28.png upload_2019-6-23_11-39-31.png upload_2019-6-23_11-40-32.png

    upload_2019-6-23_11-51-9.png
     
    Evolved4g63t and Brembo like this.
  6. ThunderChild

    ThunderChild Supporting VIP

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    Surprised no one touched that to claim a Grammar Nazi badge, too distracted by the bear in the room I guess, haha
     

    146  8

    1987 Toyota Pickup/Hilux
    awd · manual · Misc Vehicles

    Street Build 646  7

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    Street Build 849  1

    1992 Eagle Talon TSi AWD
    manual · 1G DSM

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    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  7. motomattx

    motomattx Proven Member

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    wampum, Pennsylvania
    Is your car a turbo model or non turbo? if its a turbo model a 1g cas in a turbo model can set a random misfire code.
     

    Drag Race Build 2K  16

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  8. dustyboner

    dustyboner DSM Wiseman

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    abq, New Mexico
    His talon is an ESI

    I only know this cause he mentioned it in another post.
     
  9. Justin_97DSM

    Justin_97DSM Probationary Member

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    Joined Jun 19, 2019
    Akron, Ohio
    The thing is, the check engine light does not flash. And the previous owner replaced the plugs and sensors with OEM parts. I'm starting to think it may be the computer. But I am trying to see if it could be something else before I spend 200-400.
     
  10. dustyboner

    dustyboner DSM Wiseman

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    abq, New Mexico
    have you checked the compression?

    take a look at the wiring thats close to the EGR tube. The tube gets hot and it can f*** up the wires.
    Check the EGR valve too. Make sure it isn't stuck open from carbon build up.


    upload_2019-6-24_8-40-48.png upload_2019-6-24_8-41-13.png
     
    Last edited: Jun 24, 2019
  11. Brembo

    Brembo Proven Member

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    Clifton, New Jersey
    I will say this. You guys made me laugh. I will also say that in my 12 1/2 year career as a tech I have changed a pcm like 3 times. I will also add that 2 of them never fixed the problem. One was on a 4 liter jeep, had p0201, had pulse but still missed. I told my self that it had to be a computer as I already moved the injector. Only by a chance that I was moving wires around where a miss turned into dead miss, the valve cover bolt in the back rubbed thru the wires and was massing signal wire up. Second was on e250 and that van would just stop running and voltage on the scanner would go to 7.1 volts. Though that it was very strange, checked the usual things. It turned out to be, again by chance I touched one of the ignition coils and the truck would run better, ignition coil spiking the pcm. So with that being said, I never suspect a pcm. It is always the last thing on my mind. Also the third pcm was actually bad. It was on one of those B2500, it had no 5 volt referance.
     

    Street Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  12. Brembo

    Brembo Proven Member

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    Joined Aug 17, 2014
    Clifton, New Jersey
    I would do a compression test. By doing it you will see if your ngine is even worth fixing. If all numbers are good than move on, if they are all low then check mechanical timing. I would also look into crank/cam sensors. First look for corolation or sync with each other in the scanner. They need to be sync. Then you need to hook up a scope on the signal wire and look at the pattern of the crank sensor. You will have to find a know good pattern. You can use iatn website for that. If that checks out, then I would check into fuel trims and fuel pressure. I find it hard to believe that the car is running good and yet sets misfire codes. I would also check for 5 volt referance and powers/grounds to the crank sensor. Notice that you are not actually changing anything, it's relatively easy and simple tests. Most of these things you can find how to on you tube. We need to start eliminating things to gain some traction to keep going.
     

    Street Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  13. dustyboner

    dustyboner DSM Wiseman

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    Joined Mar 13, 2016
    abq, New Mexico
    I was thinking the same thing earlier, i have never seen a 420a PCM go bad.

    upload_2019-6-24_20-21-17.png
    download this, its the MFI section of the factory service manual: It has all the sensor checking procedures.
    http://www.mediafire.com/file/g71rpcrjbzkozep/420a_RS_GS_MFI_TroubleShooting.pdf/file

    here is the link to the main directory if you want any other reference material. http://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals
     

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