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fuel gauge problem.......again.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by riz, Jan 10, 2001.

  1. riz

    riz 3/4 ton status

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    <font color=purple> I know this has been discussed many times over the last year or so but I wanted to know what are some of the problems for the inconsistant fuel gauge ? I want to make sure my fuel level is what it reads. Thanks. </font color=purple>

    <font color=purple>L8r,

    .Riz.<font color=purple>
     
  2. FWP

    FWP CRS

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    I thought my sender had a problem, and it did. I pulled the tank, and here's what I found: The float operates an arm, with an electrical contact that contacts a coil of wire. On mine, the wiper was contact was dirty, slightly corroded, I cleaned it up with some 600 sandpaper. The resistanse from the ground wire to the wiper conact was 0 to 93 ohms, depending on tank level. As for the other problems that could occur:
    Bad ground at sender
    Bad connections, anywhere from the sender to the cluster.
    Broken gage
    Float broken off or a hole in it.

    Hope that helps. Any particular symptoms Riz?

    [​IMG]
     
  3. riz

    riz 3/4 ton status

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    <font color=purple>It just seems to fluctuate all the time. I haven't had too much time lately to dig into the problem, although I will be putting a 2" body lift in soon and I heard that it is easier to get at the rear bolts if the tank is dropped. If so, it would be a good time to get the fuel gauge in order. Basically inconsistant readings from the gauge.</font color=purple>

    <font color=purple>L8r,

    .Riz.<font color=purple>
     
  4. FWP

    FWP CRS

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    Riz, Ohm it out, right at the sender, while someone rocks the vehicle. The reading should stay stable(within a couple of tenths of an ohm. If it jumps all over the place, you got worn or dirty parts in the sender- If not, It'll save you from dropping the tank.

    [​IMG]
     
  5. riz

    riz 3/4 ton status

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    <font color=purple> Thanks, I'll look into that as soon as I get some free time and the weather stays on the warmer side here in Wisconsin for a few days.</font color=purple>

    <font color=purple>L8r,

    .Riz.<font color=purple>
     
  6. HarryH3

    HarryH3 1 ton status Author

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    The fuel gauge on all of my K5's "wandered" a bit while driving. I just always figured it was due to the fuel sloshing around in that cavernous tank! [​IMG] I've seen it move by as much as a quarter of a tank after taking a turn. Is this what you're seeing?

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  7. kpanza

    kpanza 1/2 ton status

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    Mine works fine until it hits about 1/2 tank, then it doesn't go any farther?? It just hovers at the 1/2 mark until I refillit, then it reads Full until it goes back down to 1/2 again! I had this happen a long time ago, and one day we were fixing something on the truck, and my friend (since he owns a Furd, he likes to drop my truck off the jack and see how tough it is) well, he dropped it and lo and behold, that week my gauge went all the way down to empty! It stayed that way until I replaced the fuel pump and remounted the fuel bladder in the bottom of the tank (it broke off its mount), now it is back to the old 1/2 full problem...must be a "sticky" float, or something is catching on it, huh?? It really sucks, since I only get about 9-10 MPG, I am always worried about running out, and with teh big tires my odometer isn't correct, so is hard to keep track of the miles!!! Arrrggggghh!!! But, I now carry two jerry cans with me on any trip, just in case...
     
  8. HarryH3

    HarryH3 1 ton status Author

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    kpanza, sounds like your float is getting stuck and is not able to move through the full motion. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  9. kpanza

    kpanza 1/2 ton status

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    That is what I figured, and it stinks because when we were in there replacing the fuel pump, we made sure that the float was moving freely!! I guess something moved, who knows?

    HarryH3...about your gauge moving when you round corners...I think that is due to your fuel tank baffle coming loose. The bottom of the tanks have a plastic-rubber baffle that is designed to keep the fuel from sloshing as much when you get down to lower fuel levels. My mechanic buddy at the GMC dealer said that he sees a lot of these break where the "feet" attach to the tank. They use bolts to hold them down, and the plastic often cracks around the bolt, and then the baffle moves around when us four wheelers bounce around off road (or in my case, it actually broke off completely and was sitting sideways in the tank!). Just a suggestion, I would check that if you ever have the tank down. We fixed it by using some large fender washers so that there was less stress on the area around the bolt...
     
  10. Confederate9

    Confederate9 1/2 ton status

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    mine works, but as i make turns it will go down and up, doesnt bother me too much cause if it gets on 1/8 of a tank it freaks me out and i fill it up, i usually dont get down past a 4th jsut in case i have to go for a long drive.

    Confederate's w/ K5's!
    '85 K5: BIG BAD AND MEAN
    K5: Because size DOES matter
     
  11. HarryH3

    HarryH3 1 ton status Author

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    kpanza, that baffle must be used on later rigs. I've been into the tank on my '75. Had to modify things to use an electric (external) fuel pump and return line for the TPI system. There was nothing in that tank except the fuel pickup and sending unit. The rest is just a 32 gallon hole. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     

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