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"Running on Empty"

Discussion in 'Gen 3 Prius Main Forum' started by lutece7, Sep 24, 2009.

  1. lutece7

    lutece7 New Member

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    remember the old Jackson Brown song "Running on Empty"? well that is me. I have been running on empty fo 20 miles now and I expect to be able to keep running on empty for many more miles.

    Every time I fill up my 2010 Prius, I KNOW there is still 2 gallons or 100 more miles in the tank. I think it is stupid that the computer has us fill up when we have that much still in the tank. So when my display read "0" miles to the next fill up, I zeroed out my Trip B odometer and kept driving. I have 20 miles on "empty" now. I will start carrying a fuel can tomorrow. I want to know how many mile I can go on the official 0 miles to fill up, empty mark. I think Toyota is mistaken to have us all fill up with 2 gallons still in the tank. When I run out of gas, I will have almost a mile of EV mode range, right? and then I will have my 1 gallon gas can that I am going to start carrying. Hope I am not too far from a gas station.

    Can anyone tell me why I should NOT attempt this on my precious new Prius? I don't see why not. If I get up to 80 or 90 miles "on empty" I will be satisfied and fill up then, but not before!
     
  2. OvertheHill

    OvertheHill New Member

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    Don't know if it's still the case but I was always told that running out of fuel in a modern car can damage the catalytic convertor but I can't imagine just once would be that bad?
     
  3. DavidA

    DavidA Prius owner since July 2009

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    Here's a thread about what can happen if you run out of gas in a Prius.
     
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  4. Spartane

    Spartane Member

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    Three reasons that I can think of:
    1. The electric motor in your fuel pump is cooled by the gasoline; it could overheat and this could reduce it's life expectancy.
    2. Your chance of running out of fuel is greater on a hill since the gasoline will all collect either to the front of the tank or the back. This is potentially dangerous since other cars may not see you when you run out.
    3. Over the long term, crud in the gasoline will collect and settle to the bottom of the tank. Using the last of the fuel will force this crud through the system, possibly plugging the fuel filter.
     
  5. steve44

    steve44 New Member

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    No reason at all. Go ahead buddy! (Better you f up your car than me). Have at it and post results!!! (I wonder how many years your stunt will take off your car?)

    :lalala:
     
  6. patsparks

    patsparks An Aussie perspective

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    I think it is stupid to carry a can of petrol in a car for no reason except so you can drive past petrol stations until you run your tank dry.

    Do you realise that if, like me you get about 1000km from a tank of fuel, and you drive 20,000 kilometres a year, (about average in these parts,) if you get 10% further by running the tank dry you will save filling your car once every 6 months! Whoop dee do!

    As a result of running your tank empty you might need to transfer fuel into the car in bad weather, in darkness or on a dangerous stretch of road. On top of this your hands will smell of petrol and, and this is a big and, you still have to fill the tank anyway. You will also need to fill your can.

    Also in the process, as stated above you might harm the fuel system of your car.

    Please explain the benefits again, I think I missed it.

    PS, read the pink parts of the quote, it has a message hidden in it.
     
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  7. marzprius

    marzprius Junior Member

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    Just did that a couple days ago. First & only time, just for my own info. I had a good tank going 722 mi & 68.2 mpg, my first 700 mi. tank :rockon:!
    Had a fuel can with me, got 78 mi. beyond when the last pip started blinking. So the 100 mi. you think you might get is pretty unlikely. First & last time because of the potential fuel pump damage, but now I know I can go 40-50 mi. in a pinch if I have to. Depending on terrain & avg. mpg. of course.
     
  8. David Beale

    David Beale Senior Member

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    Sure hope you don't have an accident with that gas can in the car, because they will often burst in the violence. Just what you want, trapped in a burning car full of gasoline!

    Very strange attitude, but not uncommon. As I've said in another thread, I often wonder how we have "covered the earth" being so dumb!

    Fill the tank at one or two pips. It's not a contest to see how far you can get on a tank. It's a contest to see who can avoid being killed on public roads!
     
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  9. steve44

    steve44 New Member

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  10. Codyroo

    Codyroo Senior Member

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    Bob Wilson and ACPilot64 have done this experiment. They've come to the result that you have approximately 2.1 gallons after the initiation of the blinking light.

    *edit link*

    http://priuschat.com/forums/gen-iii-2010-prius-fuel-economy/69244-800-mile-attempt-one-tank.html

    It is my understanding that, historically, auto manufacturers build in a "safety cushion" from when the tank indicator shows "Empty" and when you actually run out of gas. While I can appreciate the aggravation of not know precisely how much gas you have in your tank (I work in the sciences, and we like to know how much material we have), the vast majority of people can't be bothered with accurate and precise measurements. Thus, giving this group of people a flashing pip and a "miles to zero" indicator is sufficient to minimizes instances of running out of gas.

    Realize that you are exceptional in that you want to know this information. Car Manufacturers don't build their cars and safety margins for the exceptional, it is too small a group.
     
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  11. Blind Guy

    Blind Guy New Member

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    ...Every time I fill up my 2010 Prius, I KNOW there is still 2 gallons or 100 more miles in the tank.
    * This is ONLY true if: A) your driving has been EXACTLY the same over that tankfull, B) weather and temperature have remained EXACTLY the same as previous tankfulls, C) Settings in your car have stayed EXACTLY constant (i.e. heat, A/C, power selections and electrical settings that effect current draw) and D) Seasons, which affect fuel milage, which will dramatically effect the fuel remaining.
    There are MANY variants that determine the amount of fuel remaining in your car. DON'T depend on it being constant over a given period of time.
    I think it is stupid that the computer has us fill up when we have that much still in the tank.
    * This is to prevent running out of fuel inadvertantly, as opposed to doing it intentionally!
    So when my display read "0" miles to the next fill up, I zeroed out my Trip B odometer and kept driving. I have 20 miles on "emptynow. I will start carrying a fuel can tomorrow.
    * Good idea!
    I want to know how many mile I can go on the official 0 miles to fill up, empty mark. I think Toyota is mistaken to have us all fill up with 2 gallons still in the tank.
    * How much would you recommend Toyota leave after the last Pip (preferably in oz. I assume)?
    When I run out of gas, I will have almost a mile of EV mode range, right?
    * NO, the manual states the car will operate about 1/2 miles, at or below speeds of 25 MPH. However, if the Fuel Pump ceases due to fuel starvation (as in the case of running out of gas) the Hybrid Battery is disabled (to prevent damage to it), and thus, the EV mode will be inoperable! So your total distance after running out of fuel will be...0!
    and then I will have my 1 gallon gas can that I am going to start carrying. Hope I am not too far from a gas station.

    Can anyone tell me why I should NOT attempt this on my precious new Prius? I don't see why not. If I get up to 80 or 90 miles "on empty" I will be satisfied and fill up then, but not before![/quote]

    David (aka Blind Guy)
     
  12. Bob_Stan

    Bob_Stan New Member

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    David (aka Blind Guy)[/quote]
     
  13. Bob_Stan

    Bob_Stan New Member

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    [/quote]
     
  14. bluemonday

    bluemonday New Member

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    I can understand the sentiment, as it is a bit annoying how far off the gauge is from empty when it tells you to fill up. But it's what we got, and I really don't see the point in running it dry just to prove....something? I don't know what.
    I would say someone has already run it dry and proven you can get a decent bit on what is in your tank at "empty." I don't know what else you can learn by running yours dry other than, yep, yours can run dry too.
    So I think what we have collectively learned that when the car shows empty, get some gas in a reasonable time frame.
     
  15. wvgasguy

    wvgasguy New Member

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  16. wvgasguy

    wvgasguy New Member

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    If it were simply a matter of running longer between fillups I would say ignore the gage. However Toyota designs this into their hybrids (it's like that in my HH, my Prius and my past TCH) and I would be concerned about the other issues spoken of here unless Toyota came out and said cooling your fuel pump wasn't an issue and it was simply a reserve. Guessing at what the designers had in mind could cost money if your're a long term owner and you don't follow their guidelines.
     
  17. wvgasguy

    wvgasguy New Member

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    Better yet, why not every evening when you park you just add a gallon or two?
     
  18. raidbuck

    raidbuck New Member

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    I'm confused. I thought the car wouldn't run, even in EV mode, when empty. I remember someone else driving on a lot till he ran out of gas and he couldn't move the car at all.

    I'm also confused about this reserve. I fill up at about 3 pips and put in aroun 8.5 gallons = 1.2 gallons per pip. The gas tank is 11.9 gallons (1.2 gallons per pip X 10 = 12 gallons). So obviously the pips are not consistent when they go out. Very confusing.

    Rich N.
     
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  19. bwilson4web

    bwilson4web BMW i3 and Model 3

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    There seems to be two points of view:
    [​IMG]
    and
    [​IMG]

    I think it is a personal choice and having run out of gas three times in our ZVW30 and nearly 40 times in our NHW11, my only recommendation is to be careful to watch for when the engine actually dies. Your SOC will start dipping down and it is better if you have enough to reach a safe place to refill. If the "electronic steering" light comes on, you have lost all traction battery so try to coast to a safer place ... don't panic ... deal with it.

    GOOD LUCK!

    Bob Wilson
     
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  20. bluemonday

    bluemonday New Member

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    Wow.
     
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