Bad computer?

Discussion in 'Electrical & Stereo' started by c3pbro, Jul 12, 2015.

  1. c3pbro

    c3pbro New Member

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    I think I have a bad ecm, my tuner cannot load tunes or read any errors. Is there a way to test it?
     
  2. Witzy0070

    Witzy0070 Active Member

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    Did you try another handheld?
     
  3. c3pbro

    c3pbro New Member

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    I don't have one. The bama tuner is all I have.
     
  4. Witzy0070

    Witzy0070 Active Member

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    It's not uncommon for a poor connection to cause this issue. My X2 needs to have the plug in held upwards to make a connection. Otherwise it makes a poor connection and cannot talk to the car. I have had this happen halfway through loading a tune and my car wouldn't run.
     
  5. c3pbro

    c3pbro New Member

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    Wow I didn't even think of that, gonna go give it a shot. Thank you.
     
  6. Witzy0070

    Witzy0070 Active Member

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    Trying bending the wire all sorts of ways, just be careful.
     
  7. c3pbro

    c3pbro New Member

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    Nope, download failed at 50% like before. Thanks for the idea though!
     
  8. Witzy0070

    Witzy0070 Active Member

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    That's a bad connection, I am 90% sure. You're going to have to make sure you're connection port is good, in other words make sure all the wire pins are seated properly. Then try stupid shit like only connecting the device 70% of the way in etc. I took me a good few gos of messing around to figure out what my handheld liked to make it work.
     
  9. ttocs

    ttocs Legend

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    They always recommend cleaning the connections prior to hooking up. It can be as simple as rubbing a pencil eraser over it to remove carbon or with some scotchbright to go a little deeper.
     
  10. c3pbro

    c3pbro New Member

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    I'll go give it a try
     
  11. c3pbro

    c3pbro New Member

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    No dice. I've Been in the garage now so long I killed the battery.
     
  12. Witzy0070

    Witzy0070 Active Member

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    Well, I am sure others will have suggestions that might be possibly better, but I think you might want to try another handheld.
     
  13. Chris111

    Chris111 New Member

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    It's most likely a connection issue but you can do a general electrical test for the pcm/ecm. You will need a multi meter and a test jumper or clamp. This can also be used for suspect faulty sensors if you weren't aware.

    You will need the KOEO (key on, engine off).
    First verify that you have good battery voltage by touching the leads to the terminals. Remember this number.
    Then test ground off the engine by touching the positive lead to the positive battery terminal and then touching the negative lead to the engine block or heads. You should see matching voltage.
    Now start the car and repeat these steps.

    If you see a variance larger than .4 volts with KOEO or running than you have a ground issue. Fix that first. I'm a fan of adding more and larger grounds to engines simply because electrical current will always take the path with the least resistance and it reduces the chance of ground issues.

    Hopefully you didn't have any issues so far.

    Now again you'll need to be in KOEO. Choose at least three sensors to test for power.
    Clamp the negative lead to the negative battery terminal with your test jumper or clamp so you can have both hands free to work with. Be sure not to clamp the positive lead to the positive terminal and test with the negative lead or you could fry the computer.
    Touch the positive lead to the positive terminal to verify you have a good ground with test jumper or clamp.
    Now back probe the positive wire on the three or more chosen sensors.
    You should see 5 volts at each sensor.

    If you do not see 5 volts at three or more sensors than there is one of the listed

    Bad ground issue at the pcm
    Internal short
    Faulty pcm


    This test also works for suspect faulty sensors. If you have one sensor that you suspect is faulty and you do not read 5 volts on that sensor than suspect that it is faulty.
     
  14. c3pbro

    c3pbro New Member

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    well it turns out it was a bad ECM. I pulled one from a junked car and now it runs. Still have a list of problems to work through though, I appreciate everyone's input