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Less than 100 miles on a 1/2 tank of gas???

Discussion in 'Gen 2 Prius Fuel Economy' started by tiffnco, Feb 1, 2010.

  1. tiffnco

    tiffnco New Member

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    Hi all,

    I didn't know where to go (aside from the dealer), so I'm hoping maybe someone here can help me out.

    I've had my car for just about 3 years now...and it's been working just fine. I do live in the hills, so my MPG isn't as great as it could be...but I've been averaging about 40MPG...until lately.

    I've been noticing my fuel gauge dropping faster and faster with each tank of gas. At first, I could go 100 miles before I drop one line. The past 6 months or so, it has dropped to about 80, which I still find acceptable.

    The last 2 months, I've noticed a distinct drop. And I am now on a tank of gas I got on Friday. It's Monday. I've driven 87 miles...and I'm now down to a half of a tank.

    Surely, something is wrong! I plan on going to the dealer this week...but wanted to get your thoughts and input first.

    HELP!
     
  2. qbee42

    qbee42 My other car is a boat

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    Has it been cold where you live?

    Tom
     
  3. Tgreco

    Tgreco Junior Member

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    Never really cold in So Cal !!! LOL
     
  4. JimN

    JimN Let the games begin!

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    Is the calculated fuel economy stable? IMO don't expect a miracle at the dealership. If the problem doesn't throw a code they don't look very hard to find it. I would take it to the dealer since time is short. My guess is a faulty or miscalibrated sensor. Good luck.
     
  5. tiffnco

    tiffnco New Member

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    No, not really cold for me...unless you consider 64 cold. :)
     
  6. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    It would be very helpful to know what kind of mileage you're seeing along with the gasoline consumption.

    Also, what is the state of charge of the battery? Always high? Always low? About the same as the last few years?

    Also, what's the motor sound like? Revving high? About the same as the last few years?

    All information you can possibly provide would really help.
     
  7. ksstathead

    ksstathead Active Member

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    Dirty or bad sensor sound likely. Does it sound normal when the ICE runs? If not then maybe not firing right in a cylinder.
     
  8. jdenenberg

    jdenenberg EE Professor

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    Did you happen to do a fill up of less than 4 gallons? If so that can confuse the GuessGauge and it will read low until you do a fill up that is large enough to reset the software (about 4 gallons).

    JeffD
     
  9. richard schumacher

    richard schumacher shortbus driver

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    Ditto Jeff. Otherwise:

    Does the screen still show a reasonable MPG value? If so then it may be a problem with the sensor in the tank, but it may only be natural variation in how the tank bladder folds up as it empties. Annoying, but insignificant. Keep driving and see what happens after the next fillup.

    But if the MPG number has also dropped dramatically (that is, 20% or more, say from around 50 to less than 40) or there are other symptoms, then there could be a problem somewhere else, and that's worth a trip to a dealer.
     
  10. tiffnco

    tiffnco New Member

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    According to the digital readout...about 37 mpg (I was normally running about 39 - as I stated earlier, I live in a hilly neighborhood so I know that will affect consumption.)

    I'm not sure how to check this...can you please tell me?

    Hmmm...I would say about the same. I haven't noticed a difference, so that's my assumption. I'll start to listen more closely.
     
  11. tiffnco

    tiffnco New Member

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    Nope...last fill up was 7 gallons. I usually fill up when I'm down to one pip on the fuel gauge...which normally amounts to about 8 gallons.
     
  12. tiffnco

    tiffnco New Member

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    Hey everyone,

    I wanted to come back with some updates. I had to fill up after this last tank...and lo and behold, the consumption was back to normal. So, it leads me to believe that I was a "victim" of the fuel bladder...

    Thanks for all the advice
     
  13. JimN

    JimN Let the games begin!

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    That's why it is known as the "Guess Gauge". Glad things are back to normal.