GMC 3/4 ton fuel pump?????

Discussion in 'Trucks and Trailers' started by 4curbappeal, Feb 14, 2008.

  1. 4curbappeal

    4curbappeal LawnSite Senior Member
    Messages: 761

    After putting gas in my truck a few months ago, I turned the key and the truck wouldn't start! Luckily a friend of mine who is much more mechanicaly inclined than I was there to help. He banged on the gas tank with a hammer and my truck started right up. He told me my fuel pump was going bad and if it happened again to bang on it a few times and start it up. It happened 4 or 5 times today and after banging on it for a few she started right up!
    I plan on getting it into the shop soon, but is this "band-aid" fix OK for now? How long before it won't start period? Does this sound like a fuel pump issue? Any ideas on how much this will cost? Money is pretty tight right now and it seems like every month I'm putting $ in this dang truck! Any insight would be appreciated! Thanks!

    I have also noticed a buzzing sound sometimes when I get out of the truck!
  2. 4curbappeal

    4curbappeal LawnSite Senior Member
    Messages: 761

    Sorry! Meant to post in the mechanics and repair forum.
  3. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    You need to find out if you have to pull the tank...
    I would guess you do but some cars have an access hole from the top.

    The pump itself run anywhere from 40-50 to 2-300, there's just no telling, then the labor. As for how long it will run as-is, your guess is as good as mine, one day it won't start no more, could be a year down the road, could be tomorrow.

    If you know what you're doing I've seen a guy hook one up under the hood, spliced it in and that worked, aftermarket.
  4. LindblomRJ

    LindblomRJ LawnSite Silver Member
    Messages: 2,570

    The humming seems to by typical of GM's electric fuel pump.

    If I recall correctly you will have to drop the fuel tank. A transmission jack would make the job easier.

    Again this is from memory, I don't have my repair manual at the handy.
  5. KTM

    KTM LawnSite Senior Member
    Messages: 492

    Happens quit often on GM trucks, shops will charge a lot to do it. If money is tight I would attempt it myself. Do you run your truck a lot on the lower half of the tank? If you do that can cause premature failure on pumps, its the fuel that cools down the pump. I have also herd of people mixing a little two stroke oil with there gas to get a little life out of there pump, I have never done it and it might be to late.
  6. shovelracer

    shovelracer LawnSite Silver Member
    Messages: 2,008

    definitely sounds like your pump. Ive found good ones on ebay for $120. depending on the engine/tank it could run as much as $300 at the parts store. Basically you need to drop the tank after disconnecting the lines and wiring. The new one goes in and you reinstall. Oh and you make sure the tank is clean while you have it open. The pump isnt the big labor issue its the PITA that is dropping the tank. Mostly corroded lines, fittings, and bolts. It shouldnt take them more than 2 hours. Ive heard of people cutting the floor out of the bed to easily change it, but aside from the hole you can damage the wiring or lines if your not real careful. If your not mechanical just pay someone.
  7. IA_James

    IA_James LawnSite Silver Member
    from Iowa
    Messages: 2,592

    You could take the box loose and jack it up enough to get at it rather than screwing around dropping the tank.
  8. Sydenstricker Landscaping

    Sydenstricker Landscaping LawnSite Bronze Member
    Messages: 1,281

    It is a realtively easy job to do. Get a few of your buddies over and just unbolt and move the bed. It is a heck of a lot easier than dropping the tank. Plus you dont have to lay on the ground and try to bust rusty bolts loose on the tank, etc. If you do choose to drop the tank, make sure it is near empty or empty. Gas weighs roughly 7 pounds per gallon. So it can get heavy real quick!!!
  9. lawnboy dan

    lawnboy dan LawnSite Gold Member
    Messages: 3,711

    i totally agree! i have done this job both ways and taking off the bed is easier than droping the tank
  10. KTM

    KTM LawnSite Senior Member
    Messages: 492

    It would also make a good time to fix other things like, throwing on a new pair of shocks.

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