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Why I ran out of gas?

Discussion in 'Gen 2 Prius Fuel Economy' started by theculturecritic, Mar 4, 2009.

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  1. theculturecritic

    theculturecritic New Member

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    Hello fellow Prius Lovers. Call me the dumbest Prius Nubee in the land, but I ran that sucker right out of gas on the 405 (craziest highway in LA LA Land). Can anyone help? My first week I got 432 miles before filling up fully with 9.5 gallons. With a 11.9 gallon tank, that leaves 2.5g in there (give or take). This week I figured I would see if I could get close to 500 and it died at 455? I was monitoring the system the whole time and my driving was normal and registering the standard 45 mpg. Let me know what you think. Thanks, Jeff
     
    #1 theculturecritic, Mar 4, 2009
  2. Sp33dy_gr33n

    Sp33dy_gr33n New Member

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    My advise to you is simple. When the fuel gauge is down to 1 or 2 pips, fill up with gas. Don't wait for the final light to start flashing before you purchase more fuel. There are plenty of gas stations where you live, so filling up shouldn't be a problem.

    There are thousands of posts on this website discussing the accuracy of the fuel gauge and the range of the car. Don't over think your fuel gauge. When it says you are low, refill.
     
    #2 Sp33dy_gr33n, Mar 4, 2009
  3. triumph1

    triumph1 Member

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    Run a search on "bladder fuel tank". You'll find out all you need to know. In the winter, I can't get more than 8 gallons in. Summertime I can't get more than 10. You'll never get 11 in.
     
    #3 triumph1, Mar 4, 2009
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    What did your gas gauge indicate?

    I can be snippy because I also have run out of gas. In the future, you will have your turn. :)

    Here's the short version. For the long version, browse the forums. I'm not going to be technical and many of the posters-to-come will correct my explanations. But here's how I think of it.
    The Prius gas tank is a hard tank like all other cars. However, to control emissions, that hard tank has a rubber bladder inside. It's the bladder that holds the gasoline. In the summer, rubber stretches more; in the winter, rubber stretches less. This means that you can fit more gasoline in the bladder in the summer than in the winter. Many drivers run out of gas in the cold months because they use the "I've only driven 300 miles" excuse. Additionally, there are very few people who actually get the whole 11.8 gallons into their tanks. I think I average a little less than ten and I'm fine with that.

    So yeah, when the MFD says, "get fuel" then it's time to get fuel.
     
    #4 TonyPSchaefer, Mar 4, 2009
  5. Aces

    Aces Member

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    Okay, now I want everyone here at PriusChat, who've ran out of gas with there Prius to raise there hand... (Note that mine is in the air too). Good. Wow that's a lot of hands. Now if you've ran out of gas in your Prius more than once, keep your hand in the air... (Now my arm is starting to get tired). Still a few hands. More than twice? (Finally I can put my hand down...)

    For me, try to pretend I only have a 9 gallon capacity. That works pretty well. But I still expect to run out again sometime...
     
    #5 Aces, Mar 4, 2009
  6. richard schumacher

    richard schumacher shortbus driver

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    The One True Method is: Trust The Gauge. Don't pretend that the tank is of *any* particular size. Fill the tank *before* the last pip on the gauge starts to flash.
     
    #6 richard schumacher, Mar 4, 2009
  7. Genoz World

    Genoz World ZEN-style living

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    i agree - NOBODY knows how much the bladder really takes. i'll assume 7-9, weather related of course. FILL UP AT TWO PIPS. PERIOD. DONT GUESS, DONT THINK, TWO PIPS, RUN TO THE STATION.
     
    #7 Genoz World, Mar 4, 2009
  8. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    I memorize the amount of gasoline that I put in the tank at each refill. Then I use the current MPG to calculate the number of miles obtainable. But most likely, I drive until it beeps and blinks and then I get gas.
     
    #8 TonyPSchaefer, Mar 4, 2009
  9. theculturecritic

    theculturecritic New Member

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    I never heard of a bladder. All of my other cars were pretty accurate to what they listed ... You learn something new everyday, esp. when running over an interpass in a suit and paying $15 for a .25 gas can. I'm an idiot, you are all very cool. Thanks for the knowledge, Jeff
     
    #9 theculturecritic, Mar 5, 2009
  10. bobjeri

    bobjeri New Member

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    All this bladder talk is making me want to pee.
     
    #10 bobjeri, Mar 5, 2009
  11. richard schumacher

    richard schumacher shortbus driver

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    Be sure to read the Owner's Manual and the Scheduled Maintenance Guide that should have come with the car. They contain a lot of stuff that will (mostly) save money and annoyance.
     
    #11 richard schumacher, Mar 5, 2009
  12. hill

    hill High Fiber Member

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    YOU !? :eek:

    I am SO tempted to laugh, but for the fact I'd then have my 1st "ranoutofgas" time. I regularly do the blinking pip dance, but never more than 10 miles. I've cut the dance to 6 miles, so I'd say it'll never happen, but for the fact as soon as I'd say THAT, it'd be my downfall.
     
    #12 hill, Mar 6, 2009
  13. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    You betcha I ran out of gas. After a couple years of ownership and a thorough understanding of the bladder, even. I openly admit that I usually run the tank down to the blinking point. But this was different.

    There was some talk here about bladders not filling completely, about pumps shutting off early, etc. For three tanks in a row I was fitting less and less gas in the tank. My reasoning was "I put ten in last time and only nine in this time. Clearly there's still a gallon in the tank." And then it happened again: "I only fit eight in this time, so there's still the one gallon from the nine-gallon fill-up and still that one from the ten-gallon fill-up."

    My mileage was up but my miles-per-tank was going down. So I decided to drive through the blinking pip until I decided it was time to get gas. It turns out that between me and Priapus, I'm the voting minority. When he lit up like a Christmas tree and stopped running, I lost my veto power.

    After doing the math, the number of miles I had driven and the mileage I was averaging was pretty reconcilable to the amount of gas I had refilled with.

    I have never since questioned the blinking pip.
     
    #13 TonyPSchaefer, Mar 6, 2009
  14. Celtic Blue

    Celtic Blue New Member

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    Tony,

    How much gas did it take to fill it from the flat out empty state?

    I'm sticking with filling at the flashing pip...until it's out of warranty anyway.
     
    #14 Celtic Blue, Mar 8, 2009
  15. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    #15 TonyPSchaefer, Mar 8, 2009
  16. magruder

    magruder Average Member

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    I've run out of gas in other cars, but not the Prius yet. Of course I've only had it two weeks, so give me some time. After reading all this I definitely will fill up early and not push it like I usually do. I sure am glad I filled up the first time with just one pip left. Thankfully I listened to the voice in my head saying "you better fill up, you don't know this vehicle yet". I can only get 7.5 gallons in the tank, its been very cold though.
     
    #16 magruder, Mar 8, 2009
  17. a priori

    a priori Canonus Curiosus

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    Ha! You're an idiot?! Ha!

    Read some of my threads . . . then you'll know the company you keep on this site. Don't get up on that high horse of being the idiot around these parts. Plenty have been there afore ye.
     
    #17 a priori, Mar 8, 2009
  18. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    If you read my thread you'll find that I did manage to make it to the nearest gas station. My biggest fear - and the one that keeps me from running out of gas again - is that of coworkers and friends finding out that I ran out of gas in the most fuel efficient mass-produced vehicle. The irony would be absolutely unavoidable.
     
    #18 TonyPSchaefer, Mar 8, 2009
  19. Celtic Blue

    Celtic Blue New Member

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    Ouch! Yep, trying to push ~100 miles on the blinking pip requires a bigger pair than I'm sporting!

    11.05 gallons is pretty good for a fill with the bladder. If it had been less than 9.5 gallons or so then it would be different. With the Fall weather change there were probably several factors working against you.

    One thing I'm suspecting with the MFD is that the MFD will calculate less fuel injected in cold weather than was actually pumped into the tank (which is warmer since it is underground.) The effect is small, probably not much more than a percent in the coldest weather based on some figures I found for gasoline volume change with temp. However, it does seem to fit some of the systematic shift I've seen in my fills as temperature has cooled and is now warming. Of course, for individual tanks the bladder shrinkage itself and other factors dominate. I'm not sure quite how to evaluate this statistically to screen out the other impacts, but it looks like it will take at least another full year to gather enough points to take a stab at it with my own data.
     
    #19 Celtic Blue, Mar 9, 2009
  20. patsparks

    patsparks An Aussie perspective

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    My tongue is bleeding.
     
    #20 patsparks, Mar 9, 2009
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