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Defective Gas Gauge?

Discussion in 'Gen 2 Prius Main Forum' started by kilo watt power, Jul 16, 2008.

  1. kilo watt power

    kilo watt power Junior Member

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    2008 Prius
    Picked up my prius last saturday...tank was filled by the dealer. Question is I have 142 miles on the vehicle...averaging 43.7 mpg so far...but the gauge readings still read full (as the 1st day I picked it up with 4 miles on it)...no change in reading what so ever:confused: Being in Vegas heat possible a build up of gas vapor pressure....? cause the "float" to read inaccurate. I hope this is not a dealer repair visit:(
     
  2. nerfer

    nerfer A young senior member

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    Don't worry, it'll drop pretty soon. The first bar (or pip, as they call it here) can be about 2 gallons worth, usually you have to average 50 mpg or better to get over 120 miles before the first one disappears, so the dealer was nice and really filled it up for you. (Some dealers take advantage of this and don't put in the last gallon). Most of the other pips represent about a gallon each. It depends on how much the gas bladder can expand, in warm weather it expands the most, which I'm guessing you have plenty of in Nevada right about now.
     
  3. seasalsa

    seasalsa Active Member

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    Welcome to the world of the "Guess Gauge". If you try the search feature of this site you will find that there are even contests to see just how far it is possible to go on the first pip.

    The gauge is known to be very accurate when FULL and when the last pip begins to blink.

    One word of caution, many of us try to fill the tank when we get to 2 pips. Those that try to see how far they can go on the blinking pip can expect to see a screen full of warnings, including the Triangle of Death when they run out of fuel. This can not only be very embarrassing but can lead to costly repairs.

    No need to worry about "gas vapor pressure" there is a bladder in the tank that expands and contracts with the fluid in an effort to eliminate the vapor. This is the reason that you will never be able to put the advertised 11.9 gallons of gas in the tank.
     
  4. orracle

    orracle Whaddaya mean "senior" member?

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    My gas gauge started blinking yesterday. I filled this morning and got 9.6 gallons in it. There were plenty of miles left. Don't need to be paranoid about it. You'll get a feel for when it's really empty.
     
  5. dumas

    dumas Junior Member

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    That doesn't mean there were 2.7 gallons left. With the bladder, the tank could have been empty and only 9.2 gallons would fit.
     
  6. richard schumacher

    richard schumacher shortbus driver

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    Yeah, the feeling of the car grinding to a stop.

    If you ever let the last pip start to flash you really need to buy gas immediately. There is no way to know how much *available* gas is left in the tank at that point.
     
  7. Joekc

    Joekc Member

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    I've had my Prius for eight months and saw the behavior you describe for the first time about a month ago. It never happened again. Don't worry about it.
     
  8. northwichita

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    I pushed it today, and drive my 4 year old,111K prius till the blinking last bar appeared; ~ 6.2 gallons to fill up. I'm not one to ever drive it till empty, and I take it my bladder tank has shrunk over the years . Sigh. Maybe one day I'll perform a bladderectomy. Well, they don't have em installed in the prius's in some foreign countries, right? I am dreaming of course, I'll just fill up the same (frequency) as my other chevy, and be happy with the low total bill I have to pay.

    Note, that was stopping fueling at the second click; I just read some threads on fueling, I may bring the paper with me next time and fuel at the slowest rate possible.
     
  9. kilo watt power

    kilo watt power Junior Member

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    My first 'pip" finally occured today at 180 miles..thank god for the trip odometer...thanks for the replys!;)