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!!! FUEL GAUGE !!! RAN OUT OF GAS WITH 2 BARS LEFT

Discussion in 'Gen 3 Prius Technical Discussion' started by devid, Feb 12, 2021.

  1. devid

    devid New Member

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    hi guys im new to this forum i hope you can help me out with this one.
    i have a 2010 prius with over 290 miles on the clock still running strong good economy,no oil consumption and lots of power and being reliable for the past 3 years. I live in the republic of georgia (not usa).

    last summer i was driving on the highway with approx. 2 bars left on fuel suddenly one bar added by itself making it 3 bars and after like 5 minutes i ran out of fuel had to stop on the side of the road.
    i ran out of fuel with my gauge still showing 2 bars of fuel. i verified it was a empty tank put a little gas in it started the car and then refilled at the gas station.
    after that incident i would always try to fill her up thinking it might be a stuck fuel floater.
    did this for 2-3 months then tried to bring the fuel level down again but it wouldn't go lower than 2 bars.
    ran out of fuel a couple of week ago. same problem . miscalculated the amount of fuel .again 2 bars no fuel.
    i always fill up when going half empty but this is getting annoying knowing i could drive for a week with that 2 bars of fuel.
    i don't want to start bring my car to someone whos gonna start experimenting with my car not having enough knowledge. also this is not a really common issue and there is not really much info on the web.
    since i always fixed my cars on my own i would like fix it together with your help.
    i read about the same problem with the 2 nd gen prius where you can recalibrate the fuel gauge which is not possible on the 3rd gen.
    my english isn't the best so i hope you could understand my situation.
    thank you for your time
     
  2. tvpierce

    tvpierce Senior Member

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    Welcome.

    I don't have a fix for your fuel gauge, but I have a work-around you can use until you can get it fixed: stop relying on the fuel gauge and start using the trip meter. My first three motorcycles didn't have fuel gauges, and I had a Volvo wagon for more than 10 years that never had an operating fuel gauge. Your fuel tank is 11.9 gallons. To be conservative let's say 10 gallons is usable (and because 10 is a nice round number, the math is easier for me :D ). What's your average mpg? For the sake of discussion, let's say it's 45 mpg. With that math, you simply reset the trip meter at each fill-up, and plan to get fuel at 450 miles. By using conservative estimates for fuel capacity and economy, you've built in a bit of cushion so you're not dead on the side of the road at 450 miles.
    Motorcylists have been doing this for 50 years. Once you do it a few times, it becomes second nature, and the fuel gauge becomes superfluous.
    If it still bothers you, then by all means, continue to pursue a fix. But in the mean time you can still reliably use the car without the fear of being stranded.
     
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  3. ASRDogman

    ASRDogman Senior Member

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    The float is probably sticking toward the lower end.
    You could remove the sending unit, which is accesed through a hole on the top
    of the tank under the rear seat, clean it up and hope that fixes it. Check that the
    float is not cracked and allowing fuel to get into it.
    Or just do what tvpierce said to do. :)

    To me, the guarge is just a "guide". I drive so much It's rear I go past half way before
    fueling up.
     
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Presuming you mean 290,000 miles, have you cleaned the Exhaust Gas Recirculation system and intake manifold? Those who don’t invariably have head gasket failure, and then piston failure if not addressed. More info:

    Bad Flywheel | PriusChat
     
  5. Grit

    Grit Senior Member

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    “Let's not give the OP busywork.”- chapmanf


     
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  6. mr_guy_mann

    mr_guy_mann Senior Member

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    I can think of three possible faults that could cause your problem. 1 is that something in the tank is blocking the float arm from going all the way down. 2 is that there is an electrical failure in the sender or the circuit and it cannot display "empty" even if the float is fully down. 3 is that something is preventing the fuel pump from sucking gas from the bottom of tje tank (ie, it pulls air in even though there is still gas in the tank.)
    When you fill up after running out, did it take a "complete" (maximum capacity) number of gallons/ litres? If yes then that would rule out #3. To check 1 or 2 you would have to remove the sending unit and test the system "out in the open" (while being careful about gasoline vapors and such).

    Posted via the PriusChat mobile app.
     
  7. fuzzy1

    fuzzy1 Senior Member

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    Have the gallons dispensed at these refills been consistent with the tank being fully emptied?