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running out of gas after effects

Discussion in 'Gen 2 Prius Fuel Economy' started by feethanddooth, Aug 11, 2005.

  1. feethanddooth

    feethanddooth New Member

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    after i ran out of gas a month or so ago i have not been able to get back up to the same mpg by about an average of 3 mpg. does running out of gas effect the car in a way that will make your mpg average drop for the life of the car?
     
  2. prius04

    prius04 New Member

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    There is a good deal of variability in MPG so the running out of gas could just be coincidental.

    On the other hand, gasoline is notoriously dirty and that dirt sinks to the bottom of the gas tank. Over time is accumulates. Run out of gas and it gets sucked into the system. Of course, there is a fuel filter so it should catch it all, but there is another place it can get caught.

    In the fuel injectors. Decades ago I ran out of gas in a fuel injected VW Rabbit. It cost me $80 to get it started again.

    But I doubt this is your problem. Cars are better than back then, and filters are better as well. I suspect it's simply a coincidence.
     
  3. kkister1492

    kkister1492 New Member

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    When we ran out of gas, the only things I noticed were these:

    1. After we put in the 5 gallons from the gas can, the gas gauge didn't reset and the one last bar contimued to blink until we drove to the next station and finished filling up the tank.

    2. On the next two tanks, we didn't lose the first bar until we had gone 200 miles. I was concerned that I would have to re-calibrate the gas gauge but it has settled down.

    Just before we ran out of gas, I had had the 2nd oil change and had switched to synthetic oil. I have noticed that since then I have been getting better gas mileage around town. And that has been with the AC working pretty hard. School starts in two weeks and my driving will be back to a regular routine so I'll know for sure but with the price of gas here - $2.65 to $2.85 - I'm pretty happy.
     
  4. jamarimutt

    jamarimutt New Member

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    Prius owners seem to run out of gas 10 times more frequently than owners of other cars. :roll:
     
  5. NuShrike

    NuShrike Active Member

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    You get warning signs in other cars such as the starter wheezing for a while as it tries to kick over the engine with low gas levels, unlike in the Prius.

    Also, the bladder makes the tank level a guessing game, unlike normal cars.
     
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    Question:

    if we have all that gunk/dirt sitting at the bottom that accumulates over time, how do you get rid of it?

    Also, does the bladder not take care of the bottom stuff?
     
  7. TJandGENESIS

    TJandGENESIS Are We Having Fun Yet?

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    Bladder? Does that mean there is no tank in the car? That would be odd...

    And, is this 'running out of gas' thing just because folks think the car can run forever, or faulty gas gauges, or a combo...Help out a newbie,please! Thanks! :D
     
  8. seasalsa

    seasalsa Active Member

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  9. kirbinster

    kirbinster Member

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    I think about filling mine when it gets to two bars, and wnen it gets to one I make sure I find gas that day. Why risk running out of gas -- just to be able to say you went "X" miles? Sounds like a stupid trade-off to me. Using this strategy I typically add about 9 gallons at a fill. Why risk getting stranded and possibly causing damage to engine. I just don't get the facination of taking it down to the last spoon full of gas.
     
  10. hobbit

    hobbit Senior Member

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    *Why* does this myth about "gunk at the bottom of
    the tank" remain so prevalent? THINK about it, people.
    The fuel pickup is already at the bottom of the tank, otherwise
    you wouldn't have full capacity. So any gunk that's
    going to enter the system already has done so long
    since, and hopefully caught by the filter.
    .
    The only circumstance that would increase dirt in fuel
    trying to get through the system would be if it
    was floating on *top*.
    .
    So, sorry, try again. Just once I would like to
    hear a good explanation with solid physics principles
    on how running out of gas clogs a system with
    anything other than air.
    .
    _H*
     
  11. prius04

    prius04 New Member

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    I've heard about dirt at the bottom of the tank my whole life. I'd also like a good explanation as it does seem counterintuitive when you think about it.

    But I do know I tried for hours to get my fuel injected Rabbit started on my own many years ago, after running out of gas. And the station that towed it and fixed it is extremely high on my list for being reputable. And they couldn't get it started until they did something to clean the injectors.

    So are there any auto mechanics out there who can explain this?
     
  12. kirbinster

    kirbinster Member

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    I believe there is "some" truth to it. There is junk in the fuel and it does settle and gum-up somewhat on the bottom of the tank. When you let the fuel level get very low the fuel sloshes around and the gunk is not totally covered with fuel thus the sloshing is more able to dislodge this gunk and then it gets sucked into the engine.

    I agree that it is not ordinary dirt that is pulled in, as you always pull from the bottom of the tank. It has nothing to do with running out of gas, it is never a good idea to let the tank get super empty.
     
  13. wstander

    wstander New Member

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    I am not a mechanic, but I do know that when the service station tanks get low, the silt and sludge at the bottom of THEIR tanks can get into the fill hose and thus clog your fuel system. My motorhome injectors got a bad clog coming out of Groveland, CA and I suffered for entire run from Yosemite to San Diego. Trust me, a max speed of 2mmph on the I-5 is not good;-P

    In any case, the only other fuel injector clog occurred in my diesel Jetta a few years back. In both cases, a trusted mechanic noted that there was contamination in the fuel. Inthe case of diesel of course, there is algae formation as well.
     
  14. TJandGENESIS

    TJandGENESIS Are We Having Fun Yet?

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    Still, the question I have remains...is there really a 'bladder' in there, and no metal/iron tank kind of thing?
     
  15. micheal

    micheal I feel pretty, oh so pretty.

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    Indeed, there is no metal/iron tank in the Prius, but it is a fuel bladder. I am not sure what the fuel bladder is made of, but the intent is for it to minimize any escaping gas vapors that hurt the environment.
     
  16. kirbinster

    kirbinster Member

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    Isn't the bladder inside a tank. I cannot believe there is just an unprotected rubber ball filled with gas.
     
  17. Frank Hudon

    Frank Hudon Senior Member

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    the bladder is encased in what would be the gas tank on an ordinary car. It expands to fill the tank volume under ideal circumstances. Under less than ideal circumstances it doesn't. The gas gauge sender is also located in a sub tank inside the gas tank it has a magnet on it and it changes the impedence of a coil around it there by changing the output to the computer that controls the cas gauge on the dash. The fuel pump and the fuel pressure regulator are also located in the tank. Non of the three units is a servicable piece. A problem with any one is fixed by changing the tank assy.
     
  18. TJandGENESIS

    TJandGENESIS Are We Having Fun Yet?

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    Huh! I would not have guessed that!
    Me neither.

    Wow, that is good to know. So, does this mean it safer, or not as safe, or just as safe as a 'regular' tank??? :?: :?:
     
  19. prius04

    prius04 New Member

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    Liquid gasoline does not burn, nor does it explode. It has to be in the gaseous state to do that. However, it is extremely volatile, which means it turns into a gaseous state VERY easily. This is why you should never store gasoline in your house, or in your car.

    So this would therefore make gasoline in a bladder that keeps the gasoline in a liquid state, theoretically safer.

    I say theoretically because I'm not completely sure how the Prius bladder works.
     
  20. kirbinster

    kirbinster Member

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    That is very true. I recall years ago on a bet proving to someone that I could put out a small fire by dousing it with gasoline. I did, and won the bet!

    The liquid does not burn, its just the vapor which is why the fuel is atomized before being injected into the piston chamber.