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Fuel Pump fuse popping

Discussion in 'Chevy Trucks' started by Rob, Aug 6, 2001.

  1. Rob

    Rob PlowSite.com Veteran
    Messages: 306

    A buddy of mine has an 88 2500 series chevy. A couple of months ago, just cruising down the road the truck dies. After being towed to the garage the mechanic found the fuel pump fuse was blown. Tested it trying to find why, but never found a cause. The truck has been fine since, until Saturday when again the fuse suddenly pops. This time, knowing what was wrong he put in a new one and was on his way. Got a short distance and gone again. After that, as soon as the fuse was replaced the truck would run fine until it started to move. Then the fuse would pop again. Had to get it towed to the shop, where the mechanic ran it for about an hour, no problem. But as soon as he put it in gear and tried to move it, bam fuse gone again. He tested the circuits and all looked good. Just as a test, he put a higher amperage fuse in there and is still went. He didn't have time to finish it on Saturday, so he was going to work on it today, but I'm just curious as to what you all think may be wrong with it.

    Thanks,
     
  2. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    Somewhere in the wiring harness you have a spot that goes to ground when the vehicle flexes slightly under driveline torque. You'll have to chase the wiring harness out inch by inch, literally, and find where it is getting pinched.
     
  3. raceman6135

    raceman6135 Member
    Messages: 61

    Hey Rob, Alan is 100% correct. Search inch by inch along the wire until you find where it's grounding out.

    Aren't wiring problems fun? :D

    Oh, and don't forget to put the correct amperage fuse back in! :eek:
     
  4. Rob

    Rob PlowSite.com Veteran
    Messages: 306

    Well,
    It's fixed. Thanks for all of your input. I did find out from the guy after posting this message that the fuel gauge was acting funny also. As it turns out, after tracing the wire from the firewall to the fuel tank and finding nothing, the mechanic opened up the fuel tank and found that the float in the tank had broken / bent which was causing the problem with the fuel gauge and when in just the right position and the right amount of gas would cause the fuel pump to short.

    Thanks again for all your help,
     
  5. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    When he had the tank opened up did he check that the baffle was in place and secure? There is a plastic "bucket" in there around the fuel pump and sender that keeps fuel around the pum on hills and during acceleration and turns. This bucket can come loose and move inside the tank. Had it happen to me, which is how I know about it. When it gets moving around with several gallon of fuel in it it bends the sender as well as the fuel pump plumbing. Mine was so bad the pump was almost at the top of the tank. Only cure is a new tank and any other damaged parts.
     
  6. Rob

    Rob PlowSite.com Veteran
    Messages: 306

    Don't know... that's a good question.


    The mechanic did say, though, that it looked like the arm was bent because whomever replaced the pump previously seemed to have damaged it when they 'stuffed' it in the tank.

    Unfortunately, the truck broke down while the guy was out of town, so he had to get a different mechanic to do the work. This is the reason I asked you all, so that I could see if the shop was taking him for a ride or not. Seems like it's fixed properly as the truck is running better than it has in a long time.

    Thanks again for all your help,