Gas fill over 10 gallons?!

Discussion in 'Gen 2 Prius Main Forum' started by batboy, Apr 20, 2011.

  1. batboy

    batboy Junior Member

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    Before I explain, I have easily read over a hundred posts with few directly relating to this topic. Therefore, I wanted to post and get some opinions.

    I recently (this past weekend) filled my gas tank at a gas station I do NOT typically use. Like always, I set the pump until it clicked off. I did not top off. When I saw how much it was I couldn't believe it. 10.4 gallons! Keep in mind I have never, in over a year and over 100 fills, ever gone over 9 gallons let alone 10. Yes, I have read that many go over 9, but out of all the posts I have read only one went over 10 gallons and that was after he topped off. I did not top off.

    My first reaction was a badly calibrated pump and I was considering making a complaint. However, I am now ready to refill, at least I thought. I went to refill and noticed my gauge still read 3/4 full (7 pips) and I had gone 252 miles. I typically get around 400 miles before the last pip starts flashing. As a result, I did not get any gas yet. I wanted to see how far I could go before the gauge tells me to get more.

    My concern is I have ruptured the bladder and the safety hard tank is filling up. I have done nothing to justify a rupture, but what else could it be? Assuming this is a consistent issue, will I need to take it to get fixed? I am reserving judgment and trying not to overreact, but I must admit I am rather concerned. Thoughts?

    Matt
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You don't have to worry about a ruptured bladder. The fuel tank contains a sensor that will detect fuel vapor in the space between the bladder and the shell.

    It is most likely that, on your last refueling, the fuel pump allowed a greater fill than normal. My estimate is that ~2 US gallon capacity remains after the fuel pump clicks off the first time, under "normal" conditions.
     
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  3. batboy

    batboy Junior Member

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    Excellent! I did not know about the sensor to detect vapor. Good to know there. I have read enough posts to not be surprised by severe fluctions in filling the tank; however, I thought this was extreme. I remain calm, but certianly need some validation. I hope to get that in the next few days. Thanks for the input!
     
  4. dogfriend

    dogfriend Human - Animal Hybrid

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    I've gotten over 10 gal twice since owning the car; both times I had gas spurting back out the filler pipe though. :madgrin:
     
  5. sorka

    sorka Active Member

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    I once put 23 gallons of gas in my SC400 which only holds 19 gallons if you actually run out of gas on the road. I hadn't run out of gas yet, so the pump was off by at least 4 gallons and probably more.

    Needless to say I did make a complaint to the state weights and measures board.
     
  6. ystasino

    ystasino Active Member

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    Is this estimate from mpg calculations? Care to elaborate?
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    My estimate is based upon the additional range achieved when my 2001's fuel tank was filled to the brim and overflowing, due to the fuel pump nozzle failing to click off at the normal time.

    Although no damage was caused to the fuel tank emissions control components, I don't recommend that owners deliberately overfill the tank since damage could result.
     
  8. batboy

    batboy Junior Member

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    I'm currently at 430 miles with still two solid pips left. I usually fill up before I hit 400. I have gone over 400 before but the dash was screaming at me to get gas. I'm going to try to make it home today before a fill up. That will put me near 500. At 50mpgs that's right at 10 gallons which would corroborate what the pump told me when I filled up last. We shall see. *fingers crossed*
     
  9. stefano5777

    stefano5777 Member

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    I am one who always fills over 10 gallons and also top off.As I have been boasting on this forum my last tank of fuel I traveled 700.1 miles :jaw:
    But it also took 11.5 gallons to refill so you have absolutely
    no worries
     
  10. cwerdna

    cwerdna Senior Member

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  11. Cessna157

    Cessna157 Junior Member

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    Wow! My normal fill up is almost never above 8 gallons. Being able to squeeze 10 in would be nice
     
  12. fgoodyear

    fgoodyear New Member

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    Well..... it is an 11.9 gallon tank. I have put in 0ver 11 gallons when down to 1 pip and it is blinking and telling me to put in fuel soon. Technically if it is an 11.9 gallon tank, 11.9 gallons should fit, right? I put 10 gallons in regularly when I am down to 1 pip. If you run the pump slowly you will get more in before it kicks off. Run the pump at full speed and you will never get it full. It will kick off sooner. Figure your gas mileage by miles and where the gas gauge is to see how many gallons you used. You will see that you come up short on how much gas you should have left, therefore your tank wasn't full. The bladder in a Prius is not like a regular solid tank in other cars. It has to burp the air out as it fills, like a bag. Some people have said they have had gas shoot back out when the pump shuts off. That is because the air has to escape somehow. Run it slow and it doesn't do that, and you will get a fuller tank. Done it for 87k and never had a problem with ruining anything by topping off.:rolleyes:
     
  13. qbee42

    qbee42 My other car is a boat

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    No, not right. The 11.9 gallon specification is for gross capacity. The maximum amount you can add during refueling is the usable capacity, which is always less than the gross. In the case of a Gen II Prius it is considerably less, given the volume consumed by the bladder.

    Tom
     
  14. stefano5777

    stefano5777 Member

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    Well maybe I have a Prius with a big bladder since I consistently put over 10 gallons of fuel with last fill up over 11 :0 I am a slow filler I do not like to stop for fuel but after reading all this I guess I have to stop more often
     
  15. qbee42

    qbee42 My other car is a boat

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    Ten gallons is on the high side, but not unheard of, especially since you live in a warm climate. Generally the fuel bladder consumes one to two gallons of tank capacity.

    Tom
     
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  16. fgoodyear

    fgoodyear New Member

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    Have to disagree with 11.9 being inaccurate..... I have put in as much as 11.5 before. If I am on the last pip and it is blinking I can always put in 10 gallons +
     
  17. stefano5777

    stefano5777 Member

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    I have put in 11.5 as well before. know one is disputing that you cant put that much fuel in what is being said is by stretching bladder to its limits can cause it to burst which we all know would be very bad!
     
  18. qbee42

    qbee42 My other car is a boat

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    The 11.9 gallon figure is the gross capacity of the tank. Part of that capacity is displaced by the fuel bladder, part is unusable fuel. This makes the net capacity less than 11.9 gallons.

    On the other hand, the published tank capacity does not include volume in the filler hose and other related nooks and crannies. If you insist, you can overfill the tank and use the extra capacity contained in the hoses. This will somewhat offset the unusable capacity of the tank, although it's not a recommended practice.

    Tom
     
  19. wjtracy

    wjtracy Senior Member

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    Matt- I live pretty close to you, I get 10+ gal fill-up occassionally in summer heat only. Not since last September. However, we did have that stretch of 85F+ weather a week or so back. Does it correlate?
    I am thinking the bladder expands in the summer heat.
     
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