1. George Mercieca

    George Mercieca New Member I am in australia

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    Hi there
    I've just installed a sub tank to my 75 series ute
    So my question is
    Am I able to connect it to the main tank by tapping into the the main tank fuel lines so that the two tanks will be working together
    Will this work?
    Any advice would be greatly appreciated
    thanks in advance
     
  2. CTS2

    CTS2 New Member I am in australia

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    No. It won't work. End of story .

    If the two tanks were connected together, fuel from the higher tank would run to the lower tank and cause it to over flow. Also, if you disregarded that problem, when there was still some fuel in the lower tank, it would start to suck air from the higher tank.

    Simple really.

    It's probably a diesel, but you will have to confirm whether it's diesel or petrol before I can suggest how to connect it up.
     
  3. Animal Mother

    Animal Mother Well-Known Member Supporter I am in wales

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    Many Frontrunner tanks work as an "upper" tank were they are in line with the main tank from the filler so that the fuel gauge will indicate full, and the main tank will remain full while the "sub tank" empties. Only when the "sub tank" is empty does the main tank start to indicate fuel that's being used. I'm not sure why the main tank would "overflow" as per CTS2's reply, as the main tank will be a sealed unit.
     
  4. Chas

    Chas Well-Known Member I am in england

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    That's exactly what I have in my 80, no overflowing, works a treat, better than having to have transfer pumps to transfer fuel from one tank to another. Just fill from usual filler tube to sub tank which then gravity feeds the main tank. :dance:
     
  5. George Mercieca

    George Mercieca New Member I am in australia

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    It's a diesel, 1998 75 series ute 1hz
    I've put the tank in now I just want to plumb it up. Ideally I would like to find a wreak with the parts but I'm finding it hard to find one.
    So just trying to find another way
    Thanks
    Both tanks are 90 litres
     
  6. CTS2

    CTS2 New Member I am in australia

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    Because it's not a sealed unit, therefore fuel will overflow out of the breather.
     
  7. CTS2

    CTS2 New Member I am in australia

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    Okay. So you will have two fuel lines, a large one which supplies the fuel and a small one which is fuel return.

    The factory way of doing it, is to connect the hoses from both tanks to a solenoid valve which is actuated by a switch on the dashboard. There is a solenoid valve for the supply line and another for the return line. The solenoid valves are quite expensive so a wrecker would probably be your best bet.

    If you don't want to do it this way, then you could hook up the hoses to taps that you have to get underneath and turn manually to swap tanks.

    Quite a bit of fuel circulates through the return hose for lubrication and cooling, so it is important to have the return going to the same tank as the supply is currently coming from.
     
  8. CTS2

    CTS2 New Member I am in australia

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    Here you go

    1541540551820-871776784.jpg 1541540574424-915369605.jpg
     
  9. George Mercieca

    George Mercieca New Member I am in australia

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    Ok thanks, so one solenoid is connected to the large or main fuel lines and the other to the small or return fuel line?
    And both solenoids are wired together and then plug into another plug near the gearbox?
     
  10. CTS2

    CTS2 New Member I am in australia

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    They plug into two plugs of the main loom just above the RH chassis rail, about where the transmission is. Do you have the sub fuel gauge and switch on top of your dashboard like in the photo?



    1541624541852-763453760.jpg
     
  11. George Mercieca

    George Mercieca New Member I am in australia

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    No mate I wish (you didn't have a spare one do you?)
    So I was thinking I'll get the solenoids and wire them to a switch and then I would have to wire up a separate fuel gauge.
    Trouble is I'm not sure how, and if it'll work
    Might have to have a chat with an auto electrician
    Fitting the tank was the easy part
     
  12. CTS2

    CTS2 New Member I am in australia

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    Yeah righto, the reason I asked was that there is not much point connecting the solenoids into the loom if there is no switch at the other end to power it.

    It would be simple to just power the solenoids with a switch as you suggest.

    However, you may be horrified at the price of them, in which case a couple of three way taps might do the job for you? Bit of a hassle having to turn taps to swap tanks, but so is giving a Toyota dealer hundreds of dollars.

    Screenshot_20181109-071948.png
     
  13. George Mercieca

    George Mercieca New Member I am in australia

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    Thanks mate
    I'll keep looking for parts or a wreck
    I suppose the values can be the last resort
     
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