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How much fuel left?

Discussion in 'Prius c Fuel Economy' started by johnhlong, Oct 6, 2013.

  1. johnhlong

    johnhlong Junior Member

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    How much fuel is left in the tank when the fuel gauge reads 1 bar?

    How much fuel is left in the tank when the low fuel warning starts blinking?

    John
     
  2. steveoknievo

    steveoknievo Member

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  3. bilzhorse

    bilzhorse Junior Member

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    Only did this one time. Last fuel bar blinked and then I drove 16.1 miles and filled up with 8.6 gallons.
     
  4. ztanos

    ztanos All-around Geek!

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    ~1.5 gallons left. Depending on how you drive, that's a lot of miles. I usually go 50 miles after the light kicks on.
     
  5. orenji

    orenji Senior Member

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    Why does cruise range show 0 miles left, but I still have 2 bars left of gas?
     
  6. johnhlong

    johnhlong Junior Member

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    Simple answer:

    Cruse range is based on hitting the reserve level in the tank not an empty tank.
    So you should have ~1.5 gal or somewhere around 80 miles left to drive (varies based on the MPG you get).

    A safety feature ?????

    John
     
  7. ztanos

    ztanos All-around Geek!

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    Give it a mile or two and it will start flashing only 1 bar.
     
  8. orenji

    orenji Senior Member

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    Yes it did start flashing, that is when I stopped and filled it up, and got 420 cruise miles left, so is the computer saying I am averaging 420 miles between fill ups?
     
  9. ztanos

    ztanos All-around Geek!

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    Not necessarily. Toyota left themselves ~1.5 gallons as a buffer so that idiots wouldn't run out of gas and blame the car. If you look at my fuelly signature below, you will see that I'm averaging about 500 miles per tank with the same MPGs as you are. My car says that I can travel around 475 when I refill my car. The more fill ups you do, the more the car learns what your MPGs will most likely be and starts you closer to that data point.
     
  10. johnhlong

    johnhlong Junior Member

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    As fate would have it I just got down to where the range left = 0. One mile later the bottom line started to blink on the fuel gauge. There was a gas station right there so I pulled in.

    It took 8.129 gals using slow fill rate and I let the pump click off by itself. I then managed to add an additional .274 gals to where it wouldn't take any more. (I know, but I was doing a bit of driving right after fill-up to use the excessive gaso_O ).

    So.... On my car I should have had about 1.371 gals of gas left in the tank or about 71 miles left (calculated at 52 MPG).

    Question ???? Is the 1.5 gals left in the tank from when the bar blinks or when the bottom bar disappears?


    John
     
  11. fuzzy1

    fuzzy1 Senior Member

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    I shouldn't speak for the 'c', but on the older models, the bottom bar never disappears. The blinking bar is the last warning until the engine quits.
     
  12. ztanos

    ztanos All-around Geek!

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    Usually the bar blink and the 0 are the same.


    Edit:
    As pointed out to me, this was my 1776th post. I'm a Priuschat 'Murican Patriot. :D
     
  13. chuckiechan

    chuckiechan Member

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    I think 30 miles is safe. I got in the habit of resetting the trip odometer when the light came on, each time going a little farther. But in some cars, the fuel reserve also is there to help keep the fuel pump from overheating, shortening it's life. I have no idea if this applies to the Prius. Someone else can answer that for us.

    The tank is 11.8 gallons according to the specs, so theoretically you can get ~ 10 gallons @ say 46 MPG for a fairly safe 460 miles and leave yourself with 1.8 gallon in reserve for a possible 82 additional miles. You don't know where the fuel intake line goes. You may start to sputter at anytime on hills or turns. And that may or may not be OK with your car's electronics.

    Personally, I feel that running out of gas is very poor judgement. On battery, you'll be going ~ 20 MPH on streets where the traffic is going 45 or higher. You'll be lucky to make it to a gas station alive. I'd advise against it.

    Also, in my experience the mileage numbers IMO, are backward. I get around 46 in town - I guess due to heat and air conditioner demands - and 52 or better on the highway, with or without air. The window sticker says 51 city/48 highway. I've never had those numbers in my old Prius or my new one.
     
  14. ztanos

    ztanos All-around Geek!

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    This is the prius C forum. We have a 9.5 gallon tank. When the car says 0 we have ~1.5 gallons left. I push it 50 miles every time and haven't had an issue. But you are correct about the fuel pump needing the fuel to keep cool, which is why I only do the 50.
     
  15. ShirLit

    ShirLit Junior Member

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    I'm just reading this thread because I'm getting down on my first tank of gas. I was thrilled when I'd gone 250 miles and still had half a tank left (according to the graph) and then BAM, the bars started dropping faster!! NOOOO!!!! :mad: I now have two bars left with 350 miles on the car. Since I'm not willing to push it to find out where the bottom is, is it wise to fill up when you're down on the last bar? Or should I wait until it starts blinking and making me nervous? I guess it really isn't going to change the mileage before it's really low - right?
     
  16. ztanos

    ztanos All-around Geek!

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    When the car beeps and says 0 miles you have ~1.5 gallons of gas left. If you are uncomfortable with "pushing" the envelope, then this would be a great spot to refuel.
     
  17. The car stays at 10 bars longer than at lower numbers. Here is what I recall from my Ultragauge readings, after a few road trips on the highway and after calibration:
    Totally full tank: at 9.5 gallons
    From 10 bars of fuel to 9 bars of fuel: at 7.9 gallons (loss of 1.6 gallons)
    From 9 bars of fuel to 8 bars of fuel: at 6.8 gallons (loss of 1.1 gallons)
     
  18. fuzzy1

    fuzzy1 Senior Member

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    The first tank is not the time to push it. Been there, done that, had to call for help on a long-ago car that ran out with the needle still above 'E'.

    Fill up now, see how much it takes, and keep a fuel logbook. Then, if you are comfortable with the results so far, you can start pushing farther on later tanks. But push it only in circumstances where failure is not too inconvenient or dangerous.

    Paraphrasing another senior poster, who ran dry in a Gen2 with the infamously unpredictable fuel bladder (fortunately not present in your 'c') just 7 miles into the blinking bar:

    * With your mother-in-law in the car, fill up at 3 bars. She will always remind everyone that you ran out and stranded her.
    * With your spouse in the car, fill up at 2 bars. She will always remind you that you ran out and stranded her.
    * When driving alone, fill up at 1 bar. No one else needs to know that you ran out and got stranded.

    (Personally, I often go well down into the blinking zone with my liftback during benign conditions, to get a feel for what is there just to be ready for future emergencies. See past stories. But I don't do this during bad weather or hazardous conditions that otherwise are not emergencies. And I first tested multiple times at increasing lower levels to make sure my gauge wasn't seriously off in its reading.)
     
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  19. ShirLit

    ShirLit Junior Member

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    Ok, good advice. I'm curious, how accurate is the trip meter's readout on the mileage? Will I be disappointed or thrilled? It's saying I'm averaging between 51 & 52mpg, which seems like a fairly common 'fuelly' number.
     
  20. minkus

    minkus Active Member

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    Mine usually overestimates by about 2 mpg, with a range of +-1.

    If yours says 51.5, it's probably actually ~49.5.
     
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