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gas mileage and how ICE engine cuts on/off

Discussion in 'Gen 2 Prius Main Forum' started by camner, Sep 15, 2010.

  1. camner

    camner Junior Member

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    I'm a happy owner of a 2007 (non-touring) Prius. So happy, in fact, that when it was time to replace my 1998 Camry, I bought another 2007 Prius (touring this time, with about 22K miles on it after 4 years of service).

    What I'm noticing is that the gas mileage on the "new" 2007 is at least 5 mpg lower than on the one I bought new (same driver, same daily routine, etc.). I'm also noticing that the "new" car's ICE is slower to cut out than on the first vehicle (it stays on longer when stopped at a stop light, doesn't cut out as quickly when coasting downhill, etc.). It's not dramatically different, but noticeably so. That probably accounts for the MPG difference.

    Is the "delay before ICE is cut" an adjustable item? Or do I just figure I lucked out on the first vehicle and eat worse mileage on the second one?
     
    #1 camner, Sep 15, 2010
  2. 2009Prius

    2009Prius A Wimpy DIYer

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    #2 2009Prius, Sep 15, 2010
  3. ksstathead

    ksstathead Active Member

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    Not adjustable, but it could be correctable if something is degraded.

    Make sure engine and cabin air filters are in good shape.
    Make sure oil is not over-filled.
    Maybe try cleaning the MAF sensor.
     
    #3 ksstathead, Sep 15, 2010
  4. qbee42

    qbee42 My other car is a boat

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    Look at your tires first. Touring Prius are often equipped with performance tires, which favor grip over mileage.

    Your longer running ICE may be a symptom, not the cause. If your car gets lower mileage, it means the ICE must run more or harder to provide the additional power. Since it doesn't coast as well going downhill, the engine has to push a bit more.

    Tom
     
    #4 qbee42, Sep 15, 2010
  5. camner

    camner Junior Member

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    Thanks all for your responses. The reason I think it may (but I'm not sure) it's a cause rather than a symptom is that the slower "cut out" of the ICE happens when I'm at a dead stop (at a light, say) in addition to while I'm coasting. I wouldn't think tires would impact that.
     
    #5 camner, Sep 18, 2010
  6. cwerdna

    cwerdna Senior Member

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    No, but the wrong tires will negatively impact mileage. Please indicate the make, model and size of your tires along w/what pressures you have them at.
     
    #6 cwerdna, Sep 18, 2010
  7. camner

    camner Junior Member

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    Yokohama avid envigor 195/55R16 87V

    36psi all around

    I know increasing the psi will improve mileage, though the ride will get rougher. But, for comparison purposes, I'm comparing the mpg against a Prius that is identical (year) and gets higher MPG except that the higher MPG Prius is non-touring and has the OEM tires that came with the non-touring Prius in 2007 and the one with lower MPG IS touring and has the tires specified above. The other Prius also is at 36psi all around.
     
    #7 camner, Sep 18, 2010
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