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Floor access to fuel pump

Discussion in 'The Garage' started by kit, Feb 6, 2006.

  1. kit

    kit Registered Member

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    I'll likely be changing my fuel pump, in my full size 89 blazer TBI, as it's blown a fuse for no apperent reason. I intend to cut an access door in the floor, in order to avoid dropping the tank. I found it to be a great solution for a van I used to have. But can anyone give me an idea of the exact location to cut?
    Thanks
    Kit
     
  2. hack500

    hack500 1/2 ton status

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    find where the sending unit is in the top of the tank then cut approx an 8"x8" square directly above... it's a helluva lot easier than dropping the tank.
     
  3. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    might wanna check that relay before hacking up the floor...
     
  4. goldwing2000

    goldwing2000 Guest

    I've never heard of a bad relay blowing a fuse intermittantly. :thinking:

    Usually if a relay is bad, it stays bad.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    My relay connector wiring was pretty bad, I wouldn't be surprised if that hadn't started blowing fuses had I not noticed it on install.

    He didn't mention intermittent either, so it could be any sort of wiring issue, etc., as opposed to the pump itself.
     
  6. goldwing2000

    goldwing2000 Guest

    It's intermittant. I know because I'm the one who fixed it. The truck died on the freeway. After hilarity ensued (we won't go into details on that one), I checked the wiring diagram book and figured out which fuse ran the pump. We checked it and it was blown. We changed the fuse and put some gas in the tank (it was low but not empty). He drove it home and it's still running.

    What I figure happened is that the fuel got low enough to expose the pump, it over-heated and blew the fuse.
     
  7. kit

    kit Registered Member

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    Now that we've found one of the injectors to have been shorted out, would anyone suggest that that's what blew the pump fuse? With the injector changed and the new fuse, it runs fine and the pump sounds healthy. But as this had been intermittant, I don't want to trust it yet.
    Any thoughts?
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Sure an electrical problem can be intermittent...big enough bump, enough humidity, heat, all of the above, etc.
     
  9. Robert79K5

    Robert79K5 1/2 ton status

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    While I agree for the most part, I had this exact thing happen on my old S10. I didnt think it was the relay randomly blowing my fuse either for that reason, but sure enough it was.
     
  10. chrisb420

    chrisb420 1/2 ton status

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    access panel for fuel tank

    when i made my floors i left an access panel in there it is 12" x 12" and i am making a cover out of diamond plate that will screw down into two pieces of angle i welded in underneath. there are pics at webshots click below

    http://community.webshots.com/user/crb1134
     
  11. AKbigsub

    AKbigsub 1/2 ton status Premium Member

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    Has the fuse blown more then just that one time? If not, I would not call that intermittant. If it blows every once-in-a-while, that is intermittant. If this is a one time thing, just forget about it and drive on. I have seen fuses blow for no appearent reason and never blow again. OR you may have to wait until the fuse blows more regularly to figure out what is causing it.
     
  12. goldwing2000

    goldwing2000 Guest

    It only blew the fuse once but it had some bad running characteristics off and on (mostly on) before it blew.

    I'm going to chalk it up to the bad fuel injector and call it a day. If something else happens, then we'll deal with it at the time.
     
  13. goldwing2000

    goldwing2000 Guest

    Man... that thing looks... naked. :eek1:

    Thanks for the pic, though. Do you have the measurements from the edges?
     
  14. chrisb420

    chrisb420 1/2 ton status

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    the truck is not at my house (it doesn't fit in my garage) so i will try and get you some measurements over the weekend. it has come along way since that pic, the entire floor is made of 1/8" diamond plate all the way to the firewall
     
  15. kit

    kit Registered Member

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    Regardless of the present problem, I know that one day I'll need to cut an access in the floor, but will wait till then.
    Although the fuse was blow at the time of the breakdown, it didn't blow again on the drive home or the couple of tries, after that.
    As my mechanic has pointed out, it had symptoms of fuel starvation more than a couple of times before this. This time was different, only, in that it lead to a blown fuse that stopped the pump. Then, once started, carried on with what had, beforehand, been an intermittant symptom of starvation.
    While investigating the dead injector, I found electric arc marks on the inernal piston. Suggesting to me that the injector had shorted.
    Symptom or cause?
     
  16. chills88k5blaze

    chills88k5blaze Registered Member

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    I Had and access hole cut in my floor it is 8"x8" Looking back I should have done 12"x12" but I had angle metal welded the bolted the cut floor back down it is much easier to get at now. Great mod
     
  17. kit

    kit Registered Member

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    Location?

    Can you give the location of the hole? My hope is to cut without having to drop the tank. Maybe a measure back, from the floor rise( at the back seat floor) and then from side to side( from the interior box wall)
    Thanks
    Kit
     
  18. chrisb420

    chrisb420 1/2 ton status

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    just got back from playin with the truck and i measured it. it started 8 1/2" forward from the tailpan and it was exactly in the middle of the floor.
     
  19. kit

    kit Registered Member

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    Hey Thanks

    I've always thought they should come stock, with floor access.
    With a location, I feel far more confident. I'll get to it the very next time there's a problem.
    Thanks again
    Kit
     

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