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New guy needs help

Discussion in 'Gen 3 Prius Fuel Economy' started by jfhb, Oct 1, 2013.

  1. jfhb

    jfhb New Member

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    2010 Prius
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    Hello everyone. I just got my first Prius 2010 model II used almost a month ago. My first drive from work to home I got 54-56 mpg average per the display. Now I am averaging 26mpg. My drive from work is about 35 miles. I live in Orange County, CA so it's not cold here. My tire inflation is on par. I don't gas it hard from a stand still and I feather the throttle while driving trying to keep it in the ECO range. What's going on? The only reason I bought this car is to double my mpg. I was getting around 20 in my truck so this is very disappointing. Thanks in advance.

    Justin
     
    #1 jfhb, Oct 1, 2013
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    #2 bwilson4web, Oct 1, 2013
  3. jfhb

    jfhb New Member

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    II
    - Have you read this thread Yet? no. link doesn't work on the following page. ​


    - What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations)​

    just looking at the average on the computer.
    - What fuel economy are you expecting and why?​

    at least 40 mpg, because i've heard all the talk of people getting well beyond that.
    - What are the approximate outside air temps?​

    southern california, not cold, not too hot.
    - How long are your trips?​

    35miles to and from work
    How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? ​

    not sure will check
    Have you had your alignment checked? Any pulling or abnormal tire wear?​

    no. front tires worn just purchased new tires yesterday will install tomorrow. no pulling at this time.
    - How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving? most driving is done on the highway. 60-70mph some slowing on the 5fwy ​


    - What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.)​

    flat.
    - What are your tire pressures?​

    35 psi all around per the tires pressure sticker on the door
    - Is your oil overfilled? (i.e. above the full mark on the dipstick)​

    not sure will check tonight.
    - Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.)​

    2003 Toyota tacoma, automatic, not sure on the engine.
    - What region/state are you in? (if you haven't set your location)​

    Southern California
    - How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking?​

    In ECO mode. EV when I hit my neighborhood. feathering unless i have to make a sudden stop on the freeway.
    - What modes are you using, if any? "normal", EV, power, eco? ​


    - Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on?​

    not really. a few minutes. how long is good?
    - Are you driving using D or B mode?​

    D
    - HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to?​

    No try not to use either.
    - Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15).​

    factory tires and wheels.
    - If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute?​

    no.

    ​
     
    #3 jfhb, Oct 1, 2013
  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Ok,

    Your car has two trip meters. Take one for a series of tests:
    • Push POWER button twice without foot on brake - put the car powered up
    • Reset the trip meter - hold "trip" reset until the "---" show up
    • Apply brake and push POWER to "READY" the car
    Drive to work and record the miles, MPG, and average speed. Repeat the procedure on the return trip. This establishes a baseline so we can begin to understand if the mileage problem is specific to one direction or the other.

    Are the hubs or brakes running hot? If you have a non-contact, thermometer, it is possible that a dragging brake, say a parking brake, might be causing excessive drag. Measuring the temperature of the brakes after a commute is the symptom.

    How long does your '35 mile' commute take? The reason is we know MPG is a strong function of speed:

    [​IMG]
    But to reach 25 MPG takes exceptional speed or something terribly wrong. It would be unpleasant to stay within the speed limit and achieve 25 MPG but not impossible.

    The "Top Gear" program once had a race-car driver beat the heck out of a Prius with race track style driving. In effect, maximum acceleration, flooring the accelerator, followed by heavy braking that defeated regenerative braking. My testing indicates speeds of 100 mph will bring mileage into the 25 MPG range. But following "Top Gear" driving style will have a similar effect.

    Now we know low rolling resistance tires help Prius mileage. I'm assuming you are replacing all four tires with?

    If you can, get a copy of the alignment report and post a picture. The electronic power steering can mask alignment issues. Having a photo of the before and after alignment specs can give a clue as to a possible alignment problem . . . soon fixed.

    Since this is a used Prius, consider having the transmission oil changed. If you do, provide a clean, dry, water bottle and ask for at least one cup. It does not have to be analyzed but without the sample, you'll never know.

    Bob Wilson
     
    #4 bwilson4web, Oct 1, 2013
  5. wjtracy

    wjtracy Senior Member

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    As Bob says, sounds like you have some problem, we probably expect 50 MPG in your scenario. Some of the common things are oil over-fill (as you know) , your 12v batt could be low or bad (see our tests), you need to tell us what kind of tires you have, but wheel alignment, also calculate MPG by hand to make sure display is good. Heavy load is another thing.
     
    #5 wjtracy, Oct 1, 2013
  6. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    When you put the new tires on consider bumping them up to 42/40.
    Add to Bob's questions:

    How many miles are on the car?

    Has your car ever been in a major accident?

    If above is "YES", are you sure?

    Are you measuring your MPG by the tank or trip and are you hand calculating or using the MDF???

    Do you have a Bike Rack, Roof Rack, Trailer, Hitch carrier, 5th Wheel, towed Airplane?


    My guess is that you're using a running average, which can be off by a LOT depending on your driving style. I have a 2010-G3-II and I can only get 40-mpg if I try REALLY hard to, otherwise I'm in the mid-40's to low 50's.

    If you can't get at least 40mpg?
    There is either something seriously wrong with your car, you drive like a teenager, or you're towing or hauling something that you shouldn't be.

    Good Luck!
     
    #6 ETC(SS), Oct 1, 2013
  7. Former Member 68813

    Former Member 68813 Senior Member

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    I would check for sticking brake calipers.
     
    #7 Former Member 68813, Oct 1, 2013
  8. jfhb

    jfhb New Member

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    Vehicle:
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    Model:
    II
    thanks everyone. I checked the battery. Good. Checked the tire pressure again. 35psi. Stock rims and tires. Will be putting new 195/65/15 tires on it. Bridgestone's off a 2013 Prius. I am going off the average on the display. I have not gone through a whole tank yet and will calculate once done. No heavy loads, no racks. I drive very smooth. Watching the display all the time. I may be jumping the gun since I'm reading the computer's average and not calculating miles per tank. I will repost when I do. Car had a clean Carfax but who know's?
     
    #8 jfhb, Oct 1, 2013
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