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MPG not as advertised!!!!!

Discussion in 'Gen 3 Prius Technical Discussion' started by thatcrazydoglady, Feb 21, 2010.

  1. thatcrazydoglady

    thatcrazydoglady New Member

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    So, anyone care to share why, in only Houston city driving, I still have yet to get better than 42mpg (remember, this is all flatland!), and am currently reduced to only 38mpg?????? I admit, I haven't driven my 2010 Prius much since I purchased it. Since September, still only have less than 2700 miles on it and none of it for any real highway driving. But still.....!!!!!!! Is this normal????? I have to admit, I am a bit disappointed. And then I now must take said vehicle back to the dealer to get the brakes fixed (And for this, I still haven't even received anything in the mail/email, etc., etc.!!!!!!!) But, Toyota is proud of the fact that these recalls have "saved them $100million"!!!!!!!!! Hmmmm............
     
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  2. john1701a

    john1701a Prius Guru

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    Take your Prius out for a cruise on the highway and watch what happens. The MPG will shot up. 60 MPH is especially impressive.

    Nothing but short trips in a city environment is tough on efficiency of any vehicle, Prius is no exception. Of course, 38 MPG is still way better than any non-hybrid could deliver under the same conditions anyway.

    Be glad you don't have a long commute to deal with. Putting on so few miles saves time & money.
    .
     
  3. Joe166

    Joe166 New Member

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    Maybe because of the way you drive. Different people get different mileages. There have been numerous posts with suggestions on how to achieve better mpg figures, but I don't know how anyone can second guess your driving habits long distance.

    I can't compete with some of the people who have posted their numbers, but all I know is that if I get higher mileage numbers than they do, I am absolutely confident that I am getting much better mileage than I could get with any other car that I would even consider driving. I just happen to like to punch it once in a while and I don't want to dawdle in front of other people who are trying to get to work just to try to get 60 mpg. I can also state that at a steady 75 mph I got better mileage than you do, so obviously there is either something wrong with your car or your foot. I bet on your foot.
     
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    I would say short trips are killing your mileage (like it did on your old vehicle). Take a drive around town on a weekend. Drive about 20-30 miles around town so that the car is warmed up.
     
  5. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    This is true for any car, the EPA defines tests which the vendor performs. Using the results of those various tests the EPA assigns a city number and a highway number. The vendor is not allowed to advertise any other number in the US.

    Toyota HAS to use the EPA numbers. (the EPA numbers are more realistic than the European Union's numbers or the Japanese numbers, but they still only hold true if your driving is identical to the EPA tests)

    'Features' of the EPA tests: almost all tests are performed with the car already warmed up, almost all tests are with the air conditioning off, all the tests feature VERY conservative acceleration, as every car made has to be able to achieve the specs of the test.

    Prius specific 'features': the city test the EPA uses has the car idle 18% of the time, a warm Prius shuts off the engine, a cold one does not. It takes 31 minutes to perform, you may be at your destination before your Prius warms up. The EPA tests travel 44 miles in total, the Prius gets better gas mileage warmed up, you may be starting cold each morning/evening and traveling a shorter distance.

    http://www.caranddriver.com/features/09q3/the_truth_about_epa_city_highway_mpg_estimates-feature
     
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  6. Wiserone

    Wiserone Member

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    I see your frustration. Here is my non-kool-aid opinion.

    Your gas mileage is not that bad. In fact, it is not unheard of to do worse than the EPA ratings. That said, I am not going to ask you to cruise around to for the sake of enjoying the mileage.

    I drive between 40-70 miles round trip when I go to work. I would get way better mileage than you because it is flat high way driving.

    Then there is also the break in period.


    Just curious, how many MPG were you getting with your old car?
     
  7. Tom183

    Tom183 New Member

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    First: EPA MPG is not an "advertisement", it's a fact - the number the EPA got using their test regimen. That's all it means, nothing more. Your mileage WILL differ if your driving style/route does not match the EPA test pattern.

    Second: the braking issue has absolutely nothing to do with MPG, and is not that serious unless you take a lot of risks and leave no room for error.

    Third: "stomp and go" driving is bad for mpg in any car - it's just more noticeable in the Prius. If you're working through a string of stoplights, go a little easier on the gas, and take your foot off sooner when you see a yellow up ahead.

    Fourth: in cold weather, firmer tires (higher PSI) may help. (in fact, if your tires were never properly inflated, this might explain everything)

    Fifth: if you spend a lot of time between 35-50mph, do some reading about "pulse & glide", it definitely makes a difference although it was not used for the EPA testing.

    Last but not least, if your driving is lots of short trips with stops in-between, the engine will never really warm up to maximum efficiency.
     
  8. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    With the temperatures here having reached a balmy 40F I've been cruising at 65 on the interstate (and it's not flat here) and getting just over 50 real. It seems to be 5% over so 52.7 on the display is just over 50mpg at the pump. My display is currently reading 51.8. It was 52.8 before we went grocery shopping on Saturday.

    A lot really of it is about cold starts.
     
  9. bwilson4web

    bwilson4web BMW i3 and Model 3

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    So when you answered the poll about SSC-A0B not working, you hadn't gotten it, yet. So if you were inaccurate in the poll, perhaps you are having trouble calculating the mileage too.

    It is a shame that having the Prius since September, it wasn't until January 26 that you found us. No doubt, had you come earlier, we might have been able to help sooner. Still, we're pretty good about helping newbies with timely advice.

    Just a couple of quick questions:

    • Tire air pressure? - My tires lose about 1-2 psi per month and more when it turns cold. Given Sept., Oct., Nov., Dec., Jan. and most of Feb., you could be easily down over 5 psi and as much as 8 psi. This will hurt your mileage and wear out your tires.
    • Oil level? - Have you checked the oil dipstick level? We've found on earlier Prius that an overfilled engine oil will lead to worse mileage.
    At this rate, ~2,500 miles in ~5 months, it will take another 5 months to reach 5,000 miles for your first service call, about June. That could be a long stretch of misery unless you're willing to adopt some of the group suggestions.

    Recently, Ken@Japan posted the warm-up cycle and the Japanese recommendation is to warm-up the car before driving. I think there is merit in this suggestion. But it can be a little tricky understanding exactly when to drive off. Is this car parked in the sun or shade?

    Bob Wilson
     
  10. Indyking

    Indyking Happy Hyundai owner...

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    Even in the mild Houston winter, a drop from 42 to 38 in the Prius is pretty fair game, but you’re running now more than 10 bellow EPA. The question for you is: how does the MPG in your previous or current car (that drives the same routes as the Prius) compare to EPA estimates? If the other cars do or did pretty close to EPA in similar conditions.
     
  11. PriusLewis

    PriusLewis Management Scientist

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    As a non-fanatic, I have found there are two ways to improve your mileage: 1) radically change the way you drive, and drive the Prius completely different from the way you would drive any other car, or 2) drive only on a set of rollers in a building following the EPA driving cycle (which is the way the EPA numbers are produced).

    You can get incremental improvements with the usual suggestions: increase the tire pressures until it hurts (high pressure increases mileage but makes the ride abusive) and do not use the heater or air conditioner (both radically kill mileage, and both are not used in the EPA driving cycle). I have never seen 42 MPG in my 2006, so your best is already better than my best here in Denver. My commute (admittedly over a 7,400 foot high pass) in hard winter is down to 38 MPG because I run winter tires and use the heater.
     
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  12. qbee42

    qbee42 My other car is a boat

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    I have driven in Huston. Your version of city driving isn't remotely close to what the EPA considers city driving. Alternating between standing still and racing to the next traffic light will not produce good mileage, no matter what you drive.

    Tom
     
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  13. ksstathead

    ksstathead Active Member

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    Suggest we wait for the OP to provide some details... 3 brake complaint posts, poll answered that the re-flash did not work, 2 mpg complaints without ANY details, and this one indicates no re-flash done yet...
     
  14. 32kcolors

    32kcolors Senior Member

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    I had to gas up my car this morning on my way to work and did this while it's already warmed up. I was in a bit hurry so I took off in power mode after topping off and drove 10 miles (half on the street and half on freeway), not trying to conserve fuel. When I reached my destination, the trip meter registered a very impressive 53 mpg (as I always reset Trip A after topping off).

    Moral of this post--you'll get great mpg if you skip the cold starts (or short trips for this matter) regardless of your driving habit/condition.
     
  15. Indyking

    Indyking Happy Hyundai owner...

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    I agree, but driving habits can have a big impact as well. If nothing else, my previous experience with the prius has taught me how to drive more efficiently. I admit that.
     
  16. cwerdna

    cwerdna Senior Member

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    please give us more details

    Yep. OP, please copy and paste the questions from the post at http://priuschat.com/forums/gen-iii...ry-copy-paste-fuel-economy-questionnaire.html and answer to the best of your ability. It's ok to answer "don't know" for some of them.

    It would help us a lot. Otherwise we're here spinning our wheels, making guesses, throwing out suggestions that might/might not help. The others are correct about the EPA test procedure and what automakers can legally advertise (the EPA test results numbers). Besides the Car and Driver article pointed out earlier, there are a few more useful links about the EPA procedure at http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html.

    This thread also belongs in the Gen III fuel economy forum.
     
  17. mad-dog-one

    mad-dog-one Prius Enthusiast

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    I just checked the EPA window sticker for my 2010 Prius. It reads 51 city and 48 highway, with a city expected range from 43 to 59 and a highway expected range from 40 to 56, "depending on how you drive and maintain your vehicle." It seems like you're numbers are within the bottom part of the expected range. Depending on my driving, I can get numbers like yours, but I usually average between 50 and 55 MPG in a mix of city and highway driving. Either your Prius is not working properly or your driving characteristics are not conducive to the kind of mileage that is possible in your car. I hope you can figure it out so you can enjoy the economic benefit of your Prius.
     
  18. cwerdna

    cwerdna Senior Member

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    The EPA test is just a test. Did you know they don't measure actual fuel usage? Did you know they don't drive on a real road? Did you know the average speed of the highway portions are only ~48 mph? Did you know the two portions of the test that are begun w/a cold engine are each 31.2 minutes long? Did you know they use a special blend of fuel for the test?

    Please see my post #16 for details on the EPA test.

    Here's what Consumer Reports got in their testing: Most fuel-efficient cars.

    The OP needs to provide more details for us to be able to say whether it's normal and to provide hints as to how to improve.
     
  19. Ohpoh

    Ohpoh Junior Member

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    i agree with this post. If your driving less than 3-5 miles a trip, your gas mileage will will suffer. Driving more than that, you will see your mpg jump up. But it does depends on how you drive too. I consider myself an aggressive driver and i get about 47 mpg. If i drive conservative, i get about 51 mpg.
     
  20. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Column 1 Column 2 Column 3 Column 4 Column 5
    0 low MPG high MPG EPA site user counts percent
    1 35 40 4 5.6%
    2 40 45 10 14.1%
    3 45 50 23 32.4%
    4 50 55 20 28.2%
    5 55 60 13 18.3%
    6 60 65 1 1.4%
    The range of results.

    Bob Wilson