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Today's Crappy MPG

Discussion in 'Gen 2 Prius Fuel Economy' started by Spcalan1, Jun 4, 2011.

  1. Spcalan1

    Spcalan1 New Member

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    Here is the setup:
    98 degrees ( hot )
    super easy driving - all level - no hills
    everytime I 'touch' the gas - it says my average is 8-9 MPG - WTH ??

    See photo
    What could be causing this?

    I went from 11mpg with my truck to averaging 41 with the Prius - but I think I should be getting more ( based on the super easy driving )...
     

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  2. bisco

    bisco cookie crumbler

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    mfd says 40 mpg? 93 degrees, is the a/c on? might need a new 12v.
     
  3. F8L

    F8L Protecting Habitat & AG Lands

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    You may be driving it too easy and using up all of the HV battery charge which will then cause, the engine to run to recharge it. Combine that with short trips, AC usage which will also cause the engine to run when it would otherwise be off will ruin mpg.

    You should spend more time reading the sticky threads in this forum and in the Genii section.
     
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Yeah sorry but I would like some more info. I often find that when I try to "drive easy" I end up hurting my mileage. Granted, it's not as bad as what you're showing there.

    Something's going on, that's for sure. I like bisco's idea of a new 12v and with a 2006 it might be time. Have you ever drained it to the point that you needed a jump? It's been reported that when the 12v can no longer hold a full charge, the car keeps trying to top it off unsuccessfully and therefore wrecking the mileage.

    I'm sure someone will come up with the answer.
     
  5. Spcalan1

    Spcalan1 New Member

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    Yes - AC blasting 100% of the time
    Driving too easy ? I stay above 40 miles per hour - so it should be mostly gas engine.

    The 12v reads 12.6 this morning first thing... but the first time I test drove the car ( before buying it - the 12v was dead and needed a charge ).. but after a 1 day trickle charge - everything seems ok with the 12.6 in the mornings..

    I hate to say this but..... it seems the car is 'dragging' a bit in performance compared to when we got it - and I did check the foot brake!

    The car seems too heavy when taking off..
     
  6. bisco

    bisco cookie crumbler

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    something definately going on. how does it roll when you are in 'glide'? and what were your mpg's on the first few tanks?
     
  7. dabize

    dabize New Member

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    Could you have been in "B" mode?

    I did that once without noticing for 20 miles or so and the results were certainly similar; "draggy" performance, horrible mileage etc.

    Just spent the day driving a manual for the 1st time in 20 years and kept shifting into 3 when I wanted 1, so the thought came naturally to me......
     
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  8. Gary in NY

    Gary in NY Member

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    I've heard if the hybrid battery is overheated the car may avoid using it and run the ICE more. Any chance this happens after being parked in hot sun for a long time? Have you checked your tire pressure to make sure you're not driving around with any severely underinflated tires?
     
  9. flareak

    flareak Fleet Captain

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    it's the A/C. no joke. if you leave it on when your car is stopped, it drains the battery quickly and you'll lose fuel economy.
     
  10. F8L

    F8L Protecting Habitat & AG Lands

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    And when the HV battery is drained you will definitely lose power and the car will feel sluggish.

    When I proposed you may be driving too easy I was referring to slow take offs and using the HV battery too much. Try just driving it like a regular car for your first few tanks and see how it does. :)
     
  11. mikewithaprius

    mikewithaprius New Member

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    Spcalan even with AC on there is no reason for a Prius over 40 mph on flat ground to get that sort of mileage. Sorry to say since I know you recently got the car, but something is not right. Dabize has a good suggestion, you are going into D (left and down) and not B (down) with the shift stick? Also, since your battery was dead, it might be as simple as replacing it, but you already said it was at 12.6 in the morning, which is fine.

    More questions to pepper you with :)

    Within the first minute of starting the car, are you accelerating up to 40 mph/highway speeds, are you driving up a hill, or are you going slowly around a neighborhood before getting to a main road?

    The bars that you showed us, were the second and third bar going pretty constantly 40+mph? I see you must've had at least one nice downhill or a lot of stoplights...were there a bunch of lights?

    Just to let you know where I'm going with this, the performance would be very sluggish if you have to speed up a lot or go up a big hill within the first minute. I can't imagine, though, that it would be so bad as to hamper performance to that extent for the next 10+ minutes.

    Also, have you ever hit "reset" on the consumption screen you show us since you've owned the car? Holding down the ODO/button doesn't count for this purpose, I mean the touchscreen reset button. Have you manually, hand-calculated your mpgs on any gas fill-ups, and what were they?

    When you look at the "Energy" screen at different points in your trip, how many bars do you see filling up the battery icon? Are they fluctuating a lot or holding steady around 5 or 6 blue bars after you've been driving awhile? If you never look at that screen, give it a try tomorrow and let us know.
     
  12. Spcalan1

    Spcalan1 New Member

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    before today - very good in glide...
    I am only on my 2nd tank... still averaging 40-41 per both tanks.
     
  13. brick

    brick Active Member

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    Can you describe the kind of driving you do to get 41mpg? Short trips? Long trips? Low speeds or high? Hilly or flat? Lots of stops or few? Plenty of things can contribute to poor fuel economy but it's hard to know which to look into without knowing how the car is driven.
     
  14. Spcalan1

    Spcalan1 New Member

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    Not in B mode for sure = I haven't even used that function yet.
     
  15. Spcalan1

    Spcalan1 New Member

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    Funny you say that... I heard a 'fan' sound coming from the vent for the hybrid battery - passenger side back seat.. is there even a fan there? sure did sound like it

    tires are good.

    parked in hot sun? absolutely - 100% of the day - even ran the AC while parked...
     
  16. Spcalan1

    Spcalan1 New Member

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    usually the battery is quite full - sometimes green, but usually 3-4 bars most of the time.
     
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  17. Spcalan1

    Spcalan1 New Member

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    41mpg - I would consider this very conservative driving - no racing at red lights, coasting downhill when possible... playing the 'game' of trying to break fuel efficient records...
     
  18. Spcalan1

    Spcalan1 New Member

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    Tomorrow is a new day.
    I am going to not run the AC and see if I still get the sluggishness.
    I will also check the 12v to see if it gives me the 12.6 range like this morning.

    I will check back tomorrow.

    I really appreciate everyone's support and help.
     
  19. richard schumacher

    richard schumacher shortbus driver

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    Easy stuff first: check the tire pressures and the oil level. Accelerate briskly and as much as possible avoid using the brakes by coasting and gliding.

    Do you spend a lot of time parked with the car ON? That's the same as getting 0 MPG. That's perfectly fine, but unlike other cars the Prius is telling you explicitly how much that costs.

    Note that the battery system gets its cooling air from the cabin. *Not* running the A/C on a hot day can decrease MPGs by impairing battery function. If you're sweltering then so is the battery.
     
  20. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    This may be a bad idea. If you are hearing the Battery fan running near the passenger backseat, then the HV battery is overheating. (Make sure the vent is not obstructed) Turning off the A/C cannot help this, and should make it worse. You want lots of cool air folwing though that vent. (if you have pets or extremely hairy friends* you may have clogged the fan to the battery) If the battery is overheating you are only using the engine, and it is not powerful.

    http://priuschat.com/forums/gen-ii-...-fur-dirt-causing-major-battery-problems.html

    *He's the hairy, hairy gent, who ran amok in Kent.
    Lately he's been overheard in Mayfair.
    You better stay away from him, he'll rip your lungs out Jim.
    Huh, I'd like to meet his tailor.