Poor gas mileage

Discussion in 'Gen 3 Prius Fuel Economy' started by GTO, Jun 28, 2017.

  1. GTO

    GTO New Member

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    Just bought a 2014 Prius III with 59K miles. I'm on my 3 tank of gas and the mileage I;m getting is no where close to the rate MPG. I'm driving 45 miles each way to work with 33 miles on the highway and balance on side streets. My best MPG has been 38 and the worst was 35 MPG. Any suggestions what going on?
     
  2. bisco

    bisco cookie crumbler

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    welcome!
    start with tire model and pressures. then check the 12 volt. then move on to the emergency brake and calipers.
    what is your speed on the highway? are you up to date on maintenance? is it hot there, a/c blasting?
    is the oil full, air filter clean?
     
  3. GTO

    GTO New Member

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    I have checked all tire pressures and oil and filters. Car is not Toyota certified but came from Toyota dealer that replaced front brakes and replace the start battery. Could the problem be with the drive battery and if so how is checked?
     
  4. Raytheeagle

    Raytheeagle Senior Member

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    Welcome to Prius Chat (y).

    How much AC are you using? What type of terrain is the Prius subjected to?
     
  5. bisco

    bisco cookie crumbler

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    the dealer can scan the hybrid battery for voltage parameters under load.
     
  6. ibraheem

    ibraheem New Member

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    The same problem I have but the high temperature I have is up to 100-107 and the AC always on Is that normal I hope help
     
  7. fuzzy1

    fuzzy1 Senior Member

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  8. The Electric Me

    The Electric Me Go Speed Go!

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    It is very difficult to track down what might be causing a significant MPG drop with a Prius over the internet.
    All the advice thus far are good starting points.

    My suspicion?
    Is you say the brakes were replaced.
    Going entirely on a guess and instinct, the above mentioned brake drag I think could be something to investigate.
    Prius Brakes are a very important and integrated part of the entire HSD system. I would want to make sure they were replaced correctly and that nothing is happening manifesting from them. I'd get them checked out.
     
  9. FuelMiser

    FuelMiser Active Member

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    The primary thing you can do is monitor the # of bars in the battery indicator, called State of Charge, or SOC. In steady, level driving, the SOC should be between 4 and 6 bars. If your SOC spends a lot of time below 4 bars, the internal combustion engine (ICE) will spend extra time and gas re-charging the traction battery.
     
  10. FuelMiser

    FuelMiser Active Member

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    You really need to say what tire pressures you are running. Most will run more than the door jam sticker says, such as 39 front and 37 rear, to get best MPG. Also, the tire brand/model makes a big difference. Prius is quite sensitive to tire model and brand for best economy. Good low rolling resistance (LRR) tires are more expensive than standard tires, but will significantly improve MPG.
     
  11. Mendel Leisk

    Mendel Leisk Lapsed Cargo Cultist

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    Again: what speed are you doing, on the highway?

    35~38 is very low, something's going on i think. Yeah post what your tires are.

    Also, just after you stop, feel all four wheels, see if any are exceptionally hot, might be a dragging brake. Have they ever been serviced? Not sure?
     
  12. The Electric Me

    The Electric Me Go Speed Go!

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    He say's they were replaced, which is why this is an area in which I would be suspicious.
     
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  13. Mendel Leisk

    Mendel Leisk Lapsed Cargo Cultist

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    Rear brakes in particular are my "usual suspects", they are very easy to screw up, with bad results. That in itself is a poor design.
     
  14. BigalG

    BigalG Junior Member

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    My 2016 Prius seems to be out of spec. I also have a 2008 Prius which is giving exactly the same 53.4 MPG/US as the 2016 G4 model. Having driven Prius for a few years I know all the tricks to get best mpg but the 2016 wont play ball. It goes in for its warranty service to Toyota each time I tell them its got grotty fuel economy each time they tell me to change fuel from 91 to 96 octane or higher. That has to be rubbish, as the 2008 runs on 91 octane, and this G4 claims 69MPG/US. Ive suggested that the battery may be leaky or similar but the service people are adamant the octane will fix, even though owners manual states '91 octane or higher, unleaded'.
    Anyone else getting same low fuel economy?
     
    #14 BigalG, May 15, 2018
    Last edited: May 15, 2018
  15. bisco

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    even 91 is high. doesn't the manual say 87, or is that just u.s.?

    are you tracking fuel economy by the tankful?
     
  16. fuzzy1

    fuzzy1 Senior Member

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    87 is just North America. Different countries have different rating scales.
     
  17. bisco

    bisco cookie crumbler

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    thank you.
     
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