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First tank mileage question

Discussion in 'Gen 3 Prius Fuel Economy' started by Wavey, Dec 7, 2009.

  1. Wavey

    Wavey New Member

    Joined:
    Nov 21, 2009
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    Location:
    Alaska
    Vehicle:
    2010 Prius
    Model:
    II
    There's probably a whole thread about this, but here goes. I filled up today for the first time while the last bar was blinking. Our ODO reads 378 miles and I put in 10 gallons exactly, so about 38 mpg. But one of my trip meters was running since the beginning (it read 377 miles) and quoted a consumption avg of 43 mpg. What am I missing here? I'm not too concerned about the relatively low numbers as it's (A) my first tank and (B) averaging about 20 degrees (F) here in Anchorage. But what about the difference in mileage calculation? Is it due to the consistently inaccurate MFD mileage calculator which is well established here? Which do we think is the correct number?

    Thanks,

    Russell
     
    #1 Wavey, Dec 7, 2009
  2. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
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    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    I'd say three things:
    (1) the displayed MPG is consistently too high, though that seems too much to be accounted for by this alone;
    (2) the 'dealer' fill never counts, because you don't know if they filled to the same level that you do, and they almost certainly used a different pump;
    (3) you don't know how much fuel was used before your trip meter was reset. 1 mile doesn't allow for much moving fuel, but it could have done some cold idling before that reset.

    Revisit this issue after the next refill.
     
    #2 fuzzy1, Dec 7, 2009
  3. HelloMyPrius

    HelloMyPrius New Member

    Joined:
    Dec 25, 2009
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    Location:
    N. Cal
    Vehicle:
    2010 Prius
    Model:
    III
    I am still on my first tank of gas (140 miles total). My displayed MPG is at 44.6 but it has been slowly creeping up. Hopefully it will get close to 50 by the time I get my first refuel.:)

     
    #3 HelloMyPrius, Dec 28, 2009
  4. GrumpyCabbie

    GrumpyCabbie Senior Member

    Joined:
    Dec 14, 2009
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    Location:
    North Yorkshire, UK
    Vehicle:
    2010 Prius
    Model:
    III
    I find the computer readout to be almost always about 2mpg out. I have also found that filling up at different pumps and different fuel stations can make a difference too - such as one pump clicking off earlier than another and also filling up on a slope one time and on the level the next etc.

    I fill up a lot :(
     
    #4 GrumpyCabbie, Dec 29, 2009
  5. mbarrows

    mbarrows Illini Bird

    Joined:
    Jun 22, 2004
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    Location:
    Frankfort, Illinois
    Vehicle:
    2010 Prius
    Model:
    V
    My first fill up was worse than that! We went 152 miles and I put in 5.163 gallons last night. MyHybridcar.com calculated 29.4 MPG - Yuk! I hope future tanks are a lot better than that. We averaged between 44 - 46 MPG in our G2 2005 Prius.
     
    #5 mbarrows, Jan 9, 2010
    1 person likes this.
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