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Lower guage - lower fill? No more gas below 30%

Discussion in 'Gen 2 Prius Main Forum' started by tovli, Feb 14, 2009.

  1. tovli

    tovli 2023 Prius Prime replaced 09 Prius

    Joined:
    Jun 5, 2008
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    Location:
    Boynton Beach, FL
    Vehicle:
    2023 Prius Prime
    Model:
    XSE
    I've been tracking mileage at each gas guage change for the last five tank fulls and possibly see correlation between the guage reading at the time of fill-up and the amount of gas that will go in before first click shut-off.

    When I filled at 30% and 20% the pump shut off at 8.35 gallons both times. When I filled up at 10% the pump shut off at 8.5 gallons. Effectively, no extra gas went in below a 30% reading. (2% more gas went in when guage indicated 28% more needed to fill the tank.)

    Lots of people have reported the guage inaccuracies, and many people have reported less than rated capacity fill-ups, but I have not seen anyone suggesting I should fill up at no lower than 30% after any fill-up at lower guage indications.

    tovli
     
    #1 tovli, Feb 14, 2009
  2. firepa63

    firepa63 Former Prius Owner

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    Jul 23, 2005
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    Other Hybrid
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    You'll go nuts trying to figure out the 'guess' gauge and the relationship with the bladder-filled gas tank. The bladder changes with temperature, so you also have to try to figure in the ambient temperature in your calculations. My advice is to enjoy the car. Drive it as any normal car, and get gas when you are down to 2 or 3 pips.
     
    #2 firepa63, Feb 14, 2009
  3. David Beale

    David Beale Senior Member

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    It -may- be that if you drain a lot of fuel from the tank, it takes time for the bladder to expand again, thus limiting the amount of fuel you can put in "quickly" (in this case, quickly would mean the time it takes for the pump to fill the collapsed bladder volume and trip off).

    You may want to redo the test using the slowest pump setting to fill. This -may- allow more time for the bladder to expand.

    I fill the tank whenever it gets to 1/2 full (unless on the highway, where filling stations are not as readily available). I haven't noticed that behavior.
     
    #3 David Beale, Feb 14, 2009
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