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Messed up

Discussion in 'General Chevy & GM Tech Questions' started by brickborn, Feb 24, 2011.

  1. brickborn

    brickborn New Member

    I hooked my battery up backwards on my 1990 gmc suburban . Now I don't have spark or fuel ECMB fuse was popped and ECMB1 was also ,replaced ECM1 and it stayed ,replaed ECMB and it popped again ,checked one fuseable link by starter ,checked 2 or 3 up top. Nothing! Can anyone help???
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Welcome to the club. You may have burned up the trucks ECM.
  3. stephan

    stephan Rockstar 4 Years 5000 Posts

    Welcome to the club Brick. Sorry I've never done that so I can't help you, but someone will be along that can. The closest experience I had was when my mom jumped her car backwards. It burned out the exciter diode in the alternator, but it still started & ran ok, (EFI) it just didn't charge. If your alt light in on when you get it up & running, then just repl the alternator cuz doing the diode is a PITA.
  4. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    You probably toasted the PCM, at the very least. None of the manufacturers put reverse polarity protection on the computers.
  5. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    Wow..sorry to hear the news. I hope you are able find out all that was damaged quickly and it doesn't cost you an arm and a leg to fix. Please keep us posted.
  6. dualdj1

    dualdj1 Rockstar 100 Posts

    probably best off checking with junk yards and see if you can find a used PCM
  7. Chris Miller

    Chris Miller Rockstar 100 Posts

    I second that. It doesn't take very much juice at all of the wrong polarity to fry one of those.
  8. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    PCMs are pretty cheap at AutoZone. I'll get you a price later.
  9. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Cardone Reman should be well under a hundred bucks from AZ.
  10. brickborn

    brickborn New Member

    Hey Thanks for all the info . Still on same situation.still down . Checked everything even changed ECM with the one from my 89 and changed chips to match .same . Have power to coil and power to injectors but no spark and injectors won't fire.things I checked ,coil ,ignition module,fusible links , esc, the only thing left that im not sure about , is it possible for me to have fryd the chips that plug into the computer???any other suggestions or info greatly appreciated

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