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Wierd fuel gauge behavior

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by edrum, Sep 17, 2004.

  1. edrum

    edrum New Member

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    Odd thing happened today. I had to dive the 04 about 50 miles to an appointment, and the fuel gauge just started flashing. So I stopped and put $5 of gas (2.5 gallons) since I knew that once I got to my appointment, gas would be cheaper. The gauge never stopped flashing the low warning the whole time. It had me concerned, but since I knew I had put gas in, and I knew about the pecularilties of the tank bladder I decided to ignore it. I put another 60 miles on the tank before filling it. All was fine after the car was filled.

    Moral of the story; don't trust the gauge. Fill the tank all the way whenever possible.
     
    #1 edrum, Sep 17, 2004
  2. seeh2o

    seeh2o Prius OG

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    Same thing happened to me, it freaked me out, but now that I know that the gas gauge is really the guess gauge I don't freak out.
     
    #2 seeh2o, Sep 17, 2004
  3. edrum

    edrum New Member

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    If the old float gauge doesn't work in the new tank, why don't they measure how much gas is in it by weight instead? Seems to me that it would be just about as accurate as a float, and no more costly.
     
    #3 edrum, Sep 18, 2004
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Priapus encountered some odd errors this past week and reset everything. The fuel gauge was weird after that:

    As I was driving to work, I noticed three bars.
    After the "incident" I noticed four bars.
    The next day, there were only two bars in the morning and one on the way home.

    I stopped and filled up. When I started Priapus, I checked out the gauge and still only one bar. Then two (pause) then three (pause) then four, etc, until all bars were lit. Thing is, I only put 9.977 gallons in the tank which I would think corresponds more closely to 2 -3 bars.

    Everything's working fine, otherwise.
     
    #4 TonyPSchaefer, Sep 18, 2004
  5. john1701a

    john1701a Prius Guru

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    A fill less than 3 gallons will almost always not register properly, as Toyota mentions in the owner's manual.

    When I travel up north, I stop at the last station that offers low-sulfur gas and top-off the tank. That always leads to a skewed calculation and temporary confusion with the gauge. But after you use up some of that gas, the gauge settles down and figures out where the level really is. And I've seen this with both my 2001 & 2004. It's just the way the bladder & sensors behave. Everything balances out the next time you fill with a normal amount.
     
    #5 john1701a, Sep 18, 2004
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