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Something wrong with my Prius II - It takes more gas than it advertised.

Discussion in 'Gen 3 Prius Fuel Economy' started by hschen, Aug 24, 2009.

  1. hschen

    hschen New Member

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    Thank you all for all these great suggestions, comfort and encouragement. You all are right. I am a newbie with Prius and I need break-in just as the car does. Since I bought Prius simply hoping to get 3X mileage over my old 4Runner which is getting constant 17-18 on the freeway, highway or drive way, I would be upset if I failed to achieve my goal. I shall give it more time and patient.

    Thx again.
     
  2. PeteJE

    PeteJE Junior Member

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    I take my foot off the gas and feather back on. With the Hybrid System Indicator display, if you coast with foot off pedals, you will see a little indication of "charge". This causes friction and momentum loss from the car turning something to regen the battery. If you feather back on the gas so the indicator basically disappears, then you are gliding - aim for the line on the meter between "charge" and the next larger segment (basically the battery power area). Coming down a hill is where this really works for longer times - it really does feel like freewheeling along in neutral.

    If you look at the display with the little car and power sources, you will see no arrows at all indicating no power is going to the wheels or battery and the engine is off.
     
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  3. dhs

    dhs New Member

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    Think of it in terms of consumption, and you will be happy.

    At 17 MPG, you are consuming 58.8 gals/1000 miles.
    at 47, it is 21.3 / 1000 miles....
    at 50, it is 20.0/ 1000 miles.
    My Bicycle: 0/1000 miles.

    You save more gas between the 4-runner and prius *even with your mileage* then you will going to infinite MPG....
     
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  4. bruceha_2000

    bruceha_2000 Senior Member

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    Not necessarily: you can glide AND have the engine idling, VERY annoying!! Nothing like no arrows AND 70 MPG. You will only see this at slow speeds, say < 20 MPH. Higher than that it displays the max it can (99.9) which is not necessarily 'no gas infinity'. It would be nice if there was an 'engine run' light.
     
  5. PeteJE

    PeteJE Junior Member

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    I am no expert. An engine run light would be cool.

    When I "glide" as I described, the instantaneous mpg meter is pegged - I have not considered when or if the engine is idling or not under this condition.
     
  6. hschen

    hschen New Member

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    -- Update Report --

    Now I gained 1 more day of driving Prius experience. Commuting to work and back on I-405 between Irvine and LA yields much better mpg. The 5-minute bars showed my Prius were running around or above 75 mpg line most of the trip. Why? I drove by the mpg meter (always trying to keep the meter above the 50 mark) and doing only around 60-66 mph on the freeway. After exiting freeway, since the battery was pretty much charged (never full), I found I can keep the city speed at around 30 mph and Prius would be powered by electric motor only while gas engine shuts off and mpg meter stays at 100 mpg for a long stretch. I don't think this is the same as "gliding" but it sure achieve the best mpg possible - 100 mark and stay there. Well of course, until battey drain to a level then engine shall kick on and I am sure the mpg will drop. I tried to "glide", I can't do it yet.
    Later.
     
  7. PeteJE

    PeteJE Junior Member

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    That is pretty good technique - it is fun, isn't it? If you haven't found this here yet, check it out. I learned a whole lot about the HSI and possible techniques from this write up - thanks to hobbit...

    HSI



     
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  8. Salsawonder

    Salsawonder New Member

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    You know when I had "other" cars they rarely got close to the big 18 or 22mpgs that they were supposed to get either.
    Thing is the Prius (and Prius Chat) gives you a better chance at improving your MPG and general driving skills. When I still had a non-hybrid I improved my mileage significantly with that vehicle by applying my hybrid driving techniques. I live in hilly terrain so I will never achieve 50+ but I do get mid-forties around town which is way better than the 14mpg I got in the Ford Sport Trac!
     
  9. hschen

    hschen New Member

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    I am not sure I would drive my other vehicle - a supercharged 4Runner the same way as I did with Prius. To achieve the best mpg which is the purpose of buying a Prius, I have to drive so slow and smooth comparing to driving my 13 years old 4Runner. They are 2 totally different animals, each with its own purposes. I enjoy seeing 100+ mpg on Prius but I want to feel the instant supercharged power from my 4Runner.
    Just my 2 cents.

     
  10. bac

    bac Active Member

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    Let me get this straight. On a BRAND NEW auto (read: not broken in) you came within 1.2 mpg of your target, and you think something is wrong with your scoot?

    Really? :confused:

    - Brad
     
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  11. hschen

    hschen New Member

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    Brad,
    Because after reading all these posts from hypermilers who can achieve high 50 and 60 mpg, my expectation had been raised so high to see these same numbers prior to receiving my new Prius. I think I tried too hard initially. It's getting better now.
     
  12. DrJon

    DrJon New Member

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    If you take the time to read many of the posts here on PC and at various hypermiling sites, you will find that in order to really know everything about your car instantaeously, you need a scangauge like device. Toyota did a great thing with the HSI screen but it isn't a substitution for a device that plugs into the onboard computer and shows all things at any given time. The vast majority of us are not going to go that far. But we can learn a lot from those who do about how to get close and make educated guesses about what happens when and then use our limited info in our cars and experience driving and reading what others do to get really great MPG. I'm up over 60 mpg and I am realizing that I am hitting the point of diminishing returns on what I can do with the info. I have. This is where I will be satisifed. My old truck was 18 mpg so I figure I'm doing great even if I was only at 47!
     
  13. rachaelseven

    rachaelseven New Member

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    Whew. Thank goodness it's improved! For a minute there, I thought we were going to have to recommend servicing your car to replace the carbon-based bipedal input module. :p
     
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  14. wfolta

    wfolta Active Member

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    Yes, there have been many discussions on this. What someone without experience THINKS is the strength of a hybrid, what they THINK will get them good mileage... is wrong. It certainly was for me.

    So they try too hard: accelerate too slowly, try to use the battery a lot, figure braking is efficient, etc, etc, and they lower their mileage. Add to that the fact that mileage increases significantly during break-in, and then add unrealistic expectations and it's a recipe for disappointment.

    And it doesn't help it when you consider 3% low at first try as "something wrong with my Prius".

    I've had to disabuse myself of my misconceptions and I've ridden the break-in curve and am, at 2700 miles, getting 10% higher mileage in my daily commute than when I started. You'll probably experience the same thing.
     
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  15. georgew

    georgew New Member

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    I haven't read the replies posted but for what it is worth, Each one of my tanks (three so far) has yielded better mileage than the previous tank..from 48 to 53 right now.

    I also drive more naturally now and don't pay so much attention to the indicators except when I see opportunities.

    Also, since you live in California, be aware that there is ethanol in the gasoline which I hear decreases your mileage, and increases both the frequency of your gas purchases and the tax revenue for the state.

    George.
     
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  16. ken1784

    ken1784 SuperMID designer

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    Assuming you did not reset the trip display, how long have you driven at the 46 mpg mark?

    If your 36 miles driving started at 100 mile point...
    miles mpg gallons
    1 100 46.0 2.174
    2 136 48.8 2.787


    miles gallons mpg
    1 36 0.613 58.7


    You were already seeing 58.7 mpg result during the 36 mile driving.

    Ken@Japan
     
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  17. jburns

    jburns Senior Senior Member

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    Keep in mind that the difference in gas cost to you for a 6 mpg difference is a lot different at the type mileage the Prius gets than it would have been for your 4runner.

    Assuming 15,000 miles per year at 2.59 per gallon.

    4runner 18 mpg 833 gallons

    4runner 12 mpg 1250 gallons

    Difference in 6 mpg 417 gallons $1080.00



    Prius current 48 mpg 312 gallons

    Prius hoped for 54 mpg 278 gallons

    Difference in 6mpg 34 gallons $88.00


    The $88.00 per year difference in the Prius stats would be equaled by your 4runner if instead of getting 18 mpg it got 17.6. I doubt you would have even noticed that small a difference.

    It's a whole different ballgame. Just enjoy your car and know it is getting the best mileage of anything on the road.
     
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  18. hschen

    hschen New Member

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    That is a very interesting analysis, thank you, jburns. You are absolutely right.
    Again, I appreciate, Ken and all of you out there giving me valuable comments and suggestions.
    Update today: As of this morning, my current ave mpg (still in 2nd tank) climbed to 56.4 which is 1/3 city and 2/3 freeway. I still have a half tank left and I expect mpg to continue to rise. To achieve the best mpg, I do pay a price - my commuting time is longer since I drive slower (stay under 65 mph). The good side is that with Prius I probably won't get a speeding ticket anymore :)

     
  19. rrolff

    rrolff Prius Surgeon

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    My first tank (filled yesterday) got me 43.8 mpg - but I bought the car in the desert, and the first 190 miles had a huge headwind, and I was running ~80mph. It's been in ECO mode since the first mile. Next tank should change that :)
     
  20. efusco

    efusco Moderator Emeritus
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    Yea, it'll take a little longer, but I challenge you to do the math..I suspect it's less than 10 minutes longer. My 15 mile each way commute takes me on average 5-10 min longer by taking the side roads and "hypermiling" with an average speed near 30mph (ie. 30 minutes) than it took me when I drove the 'main roads' that include a 7 mile 60mph zone. There are more stop lights on the highway stretch so when I'm not moving I'm stopped for longer time periods. And I gain no time at all when I'm on the non-highway parts b/c they're essentially the same roads as my hypermiling stretch.

    And here's the biggest benefit, IMO. I am a more relaxed, happier and safer driver. While I might need to leave for work a few minutes earlier, I find myself much less stressed. You wanna pass me? Ok. You wanna drive fast...OK.

    In my Expedition I'd arrive at work with clenched teeth, frustrated with traffic, I rushed there and thus felt rushed when I got there. I took more chances and the inherent risk of the speeds were always present.

    Going slower has changed me to a type B personality...at least when I'm driving!:p
     
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