Persistent Misfire cylinder 3

Discussion in 'Engine & Drivetrain' started by Nap73, Nov 25, 2019.

  1. Nap73

    Nap73 Full Access Member

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    1-Mechanic swapped coils not injectors and the issue stayed with # 3.

    2-We also inspected / manipulated the wiring to see if the misfire could be triggered that way. But nothing.

    I’m almost to the point that I change the wiring out anyway. It’s cheap and easy. Only thing stopping me is the possibility it won’t fix the issue.

    There is no test to verify that the ECM is at fault here? From what I understand there are “drivers” that control the current sent to the coils correct?









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  2. kbuskill

    kbuskill ***CAUTION*** I do my own stunts!

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    The ECM is the driver. It pulses the ground wire of the coil when it wants the coil to spark. The other wire going to the coil will be 12v positive all the time when the ignition is on.

    Use a volt meter and check for 12v on one of the wires at the coil. If you don't have 12v on one of them with the ignition on then that is your problem.

    If you have 12V on one wire at the coil then use the volt meter on the Hertz scale to look for a pulsing signal on the coils ground wire while the engine is running.

    You could also check the same "ground" wire on the coil for continuity to ground with the engine off. If you have continuity to ground then you have a short to ground and that is your problem.
    You could also check it for voltage as it could be shorted to voltage instead.

    You could also unplug the ECM and check for continuity between the same wire on the coil and which ever pin it connects to on the ECM. If you don't have continuity then you have a break in the wire somewhere and that is your problem.
     
  3. swathdiver

    swathdiver Full Access Member

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    I shared with you how to do it, it's the process of elimination. If the first two check out ok, it can only be the ECM.
     
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  4. Nap73

    Nap73 Full Access Member

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    I’ve got my eye on a Tech2. What do I need to look for?


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  5. HiHoeSilver

    HiHoeSilver Away!

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    Software 33.004
     
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  6. Doubeleive

    Doubeleive Supporting Member

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    I would just look for one from a usa seller in case there was any issue with it upon receipt easier to send one back in the usa than to china
     
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  7. Nap73

    Nap73 Full Access Member

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    It’s a US based seller. He’s looking for $300 for it. More than likely buying it. Just want to make sure it’s running the correct software.


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  8. Doubeleive

    Doubeleive Supporting Member

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    the last software update was done quit a while ago unless it's a old used one pretty sure anything "new" on the market will have the current software (or should anyway)
     
  9. Nap73

    Nap73 Full Access Member

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    Guy doesn’t know how to check what software it’s running. What do I tell him ?

    Thanks


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  10. HiHoeSilver

    HiHoeSilver Away!

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    Boot up screen, I believe. @swathdiver @Doubeleive
     

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