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Help ! 35-37 MPG

Discussion in 'Gen 2 Prius Main Forum' started by tigerider, Nov 2, 2007.

  1. tigerider

    tigerider New Member

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    Hey Kids,
    After 1 yr and 9 months my 06 has decided to stop averaging 45 + MPG and s now getting
    a fairly consistent 36 MPG ... :( It's been the the dealer several times they say nothing is wrong
    and has re-calibrated the fuel gauge twice.

    It went in for reading near empty, and only accepting 6 or 7 gallons that has self corrected
    or the re-calibrations have helped but the mileage has dropped 25 percent overnight.

    It seems the battery is always charged or very near where it used to get down to 1/2 when at 75 mph
    with the air on. Like it's not helping where it did.

    This happen to anyone else ? I've given up on my dealer ! :angry:

    John

    Silver 06 Priusilla
    (I hate silver)
    Lite Gun Metal Gray
     
    #1 tigerider, Nov 2, 2007
  2. Stairman

    Stairman New Member

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    Any major changes in your driving habits? Any other symptoms besides low mileage?
     
    #2 Stairman, Nov 2, 2007
  3. tigerider

    tigerider New Member

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    <div class='quotetop'>QUOTE(Stairman @ Nov 1 2007, 11:14 PM) [snapback]533742[/snapback]</div>
    I took it in to the dealer because of low mileage and the tank wouldn't hold more than
    6-7 gallons in a fill up. Hence the Re-calibration... They did minor tune 35,000 mi check at 36,700

    I did put on new tires right after I left, Pirelli P-6 195-60 's this is a "acceptable" size at .05% smaller
    AA rated better speed rating and a better weight rating. (44 psi) My parking brake was a little tight as usual
    after a tune-up causing the mileage to drop a 2 or 3 MPG but this usually wares off after a few hundred miles.

    As a traveling salesman I drive a lot and on the same trip to Tucson (1000 mi. round trip) last year
    with a passenger and more equipment I got 46 + actual, this year no Passenger & a lighter load,
    I got 37.5 actual.

    When pulling a grade with the air on the battery used to help now it doesn't unless I floor it.

    I did tell this to the dealer ... they ignored it .
     
    #3 tigerider, Nov 2, 2007
  4. JimboK

    JimboK One owner, low mileage

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    The new tires are likely part of it. First, new tires typically cause an MPG hit as they break in. Second, the low rolling resistance OEM tires, though not the best for tread life and handling, are among the best in fuel economy. I replaced my OEMS tires a few months ago with Michelin Hydroedges and estimated a 5-10% reduction in fuel economy. Third, the footprint of the slightly wider tire may cost you a bit in MPG.

    Beyond that, there are so many variables that affect fuel economy, you can't make much of a judgement based on one trip. Temperature and wind, for example. If it was cooler on your most recent Tucson trip than previous trips, that would account for some difference. A 5 MPH head or cross wind will reduce MPG by as much as 10%.
     
    #4 JimboK, Nov 2, 2007
  5. tigerider

    tigerider New Member

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    <div class='quotetop'>QUOTE(JimboK @ Nov 2 2007, 04:33 AM) [snapback]533787[/snapback]</div>
    So I should expect a 25 % change because I changed to a .05 % smaller tire. Maybe 1/2 inch wider.
    Before I took it in for gas tank bladder collapsing..I was getting 44-46 mpg and my last 4 fill ups have been:
    34.5
    26. something can't remember
    37.5
    35. something can't remember

    all actual mpg
    I might try a different dealer..


    John
     
    #5 tigerider, Nov 4, 2007
  6. patsparks

    patsparks An Aussie perspective

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    The tyre compound is different. Have you ever wondered why roller skates have Polyurethane wheels not rubber? Because rubber doesn't roll as well.
    The original tyres have a silica compound tread for low rolling resistance, do your P6s?
    Try another dealer, that will do it.
     
    #6 patsparks, Nov 4, 2007
  7. donee

    donee New Member

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    Hi John,

    Have you given this a month to sort out on its own ? The tires will wear down the new edges, and the sidewalls will become more compliant. Also, they probably reset the computers during the "calibration". As I understand it, the computers relearn the car and this improves mileage. Also, are you hitting reset at each fillup ? What is your MFD mileage ?
     
    #7 donee, Nov 4, 2007
  8. Neicy

    Neicy Member

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    I know I saw something posted about how to check to see if your brakes are dragging. You drive 1-2 miles without hitting the brakes, stop and feel the drums - if they are hot your brakes are dragging. I cannot for the life of me find the post. Anyone else remember that post or what topic it was posted under? It seems to be too much a drop in mileage for it to be just new tires.
     
    #8 Neicy, Nov 4, 2007
  9. tigerider

    tigerider New Member

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    <div class='quotetop'>QUOTE(Neicy @ Nov 4 2007, 05:37 AM) [snapback]534595[/snapback]</div>
    Thanks for looking .. no problem, B)
    It's going back to the dealer again (I know ...1 more time)
    they are going to take it apart if they have to. My service advisor really seems geniune
    in trying to get it fixed.

    Thanks to all for your help though. I just want " Priscilla " to feel better soon.
     
    #9 tigerider, Nov 7, 2007
  10. richard schumacher

    richard schumacher shortbus driver

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    It's not the tire diameter, it's their composition. I'd bet there's nothing wrong with the car.
     
    #10 richard schumacher, Nov 7, 2007
  11. tigerider

    tigerider New Member

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    <div class='quotetop'>QUOTE(richard schumacher @ Nov 7 2007, 07:17 PM) [snapback]536513[/snapback]</div>
    Richard,
    Your not alone in thinking its just the tire composition,
    Here is a blurb from Perilli dot com: ( see # 4) I wish there was a standard for this.

    -Maximum Water Expulsion
    -Blocks for High Stability & Reduced Road Noise
    -Excellent Dry Handling & Braking Stability
    -Extra Low Rolling Resistance (ELRR) System: Flexibility, Smoothness & Fuel Savings

    Thx,
     
    #11 tigerider, Nov 8, 2007
  12. YoDaddyAlex

    YoDaddyAlex Member

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    what size perilli tires would work on a 07 standard prius?
     
    #12 YoDaddyAlex, Nov 10, 2007
  13. tigerider

    tigerider New Member

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    <div class='quotetop'>QUOTE(YodaddyAlex @ Nov 10 2007, 07:14 AM) [snapback]537659[/snapback]</div>
    Alex,
    a recommended size other than the oem size ( 185 65 r15) is 195 60 r 15 it is 5 % smaller and a
    little wider. I don't recommend this tire P6 because it has 4 large straight grooves that allow the car to wander back and fourth on roads with the rain grooves cut in them. Luckly there aren't too many of them left. At least around here. The smaller tire changed the RPM about 27 RPM lower at about 2500 RPM.
     
    #13 tigerider, Nov 12, 2007
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