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gas gauge goes from empty to full without filling?

Discussion in 'Gen 2 Prius Main Forum' started by priusma, Nov 24, 2009.

  1. priusma

    priusma Junior Member

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    My last tank of gas lasted a long time according to the blips. The last few days (not much driving) has been 2 blips. I was going to get gas yesterday. I started the car and the blips showed a full tank! Figuring it would go down soon as I drove a bit, I headed off to work. The blips showed full all day. Today I am going to open the gas cap, see if it changes anything, and will certainly get gas. Anyone have this happen? I did search, didn't see this exact issue. Sorry if I missed it though. BTW I am a newbie-first tank of gas got 505 miles!
     
    #1 priusma, Nov 24, 2009
  2. qbee42

    qbee42 My other car is a boat

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    I've never heard of this specific problem. Fill the tank as soon as you can. Doing so will reset the calculation, as long as you put in three gallons or more (roughly).

    Tom
     
    #2 qbee42, Nov 24, 2009
  3. swi66

    swi66 Member

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    You may have gotten everyones idea of a perfect Prius.
    It doesn't use gas, it gains gas.......LOL

    Be careful when you take off the cap, it might pour out.
     
    #3 swi66, Nov 24, 2009
    1 person likes this.
  4. dogfriend

    dogfriend Human - Animal Hybrid

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    Here is the best advice I can give a self-described "newbie": Don't trust the gas gauge and don't believe that you can get 505 miles on the current tank just because you got 505 miles on the previous one. Because of the bladder in the tank, the tank volume is variable and the gauge isn't all that accurate either.
     
    #4 dogfriend, Nov 24, 2009
  5. BAllanJ

    BAllanJ Active Member

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    I did a speadsheet of my fuel consumption from my first tank and it's been decreasing. Extrapolating forward (linear trendline fit to the data), I should be using no gas at all by the end of 2011, and after that I'll have to bleed gas out of it now and again to keep it from overflowing. :D

    I guess his 2005 has already got there. Don't know why the guy sold it to him.

    OK... more seriously, it sounds like your spouse filled it up when you were watching TV last night.
     
    #5 BAllanJ, Nov 24, 2009
  6. priusma

    priusma Junior Member

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    Ha, I love the replies. Leave it to me to have a new issue. I just filled up to the first nozzle shut off, 7.6. Now maint lite on for just a few secs upon driving, then disappears. Maybe gas guage something, maybe 80 thou service reminder? I learned not to top off the hard way, 2 fills had gas barfs, to my utter embarrassment and good luck that no one was smoking nearby. BTW dogrfriend, had 1 505 tank out of maybe 6.
     
    #6 priusma, Nov 24, 2009
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, I think this is a new one - where your gauge reads full although you needed at least 7.6 gallons. Sounds like the fuel gauge sender unit within the fuel tank has a stuck float.

    The MAINT REQD light will appear based upon an odometer "timer". It will appear for a few seconds once you have driven 4,500 miles since the timer was last reset; then will appear solid once you have driven 5,000 miles since last reset.
     
    #7 Patrick Wong, Nov 24, 2009
  8. hyo silver

    hyo silver Awaaaaay

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    Mine 'fills up' as I drive down the street, but only right after leaving the gas station. (The last few pips blink on about a block away)

    Yours is even better - glad to see the 2010 has this improvement. ;)
     
    #8 hyo silver, Nov 24, 2009
  9. priusma

    priusma Junior Member

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    Hi All, Well, I brought the car in for it's regular service and mentioned this crazy phenomena to the service dept. The guy who worked on the car gave me a big explanation and said he fixed it. Now, two tanks later, it still does the same thing. Goes down to one blip, even one blinking blip. Suddenly, usually on my way to the gas station! all or most of the blips line up. It doesn't really bother me, but for the fact that I paid for something to get fixed that didn't. I still can't quite believe that I have a problem no one else has experienced, but oh well. Love my prius anyway!
     
    #9 priusma, Jan 26, 2010
  10. Rokeby

    Rokeby Member

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    Patrick has most probably hit the nail on the head... but a gas tank
    replacement is pricey. IIRC the metal tank with the enclosed bladder
    cum fuel pump and sender goes for ~$400 salvage.

    Two other remote possibilities that should be checked out first and
    which would be much less expensive to fix are:
    * Grossly out of true fore/aft and left/right angle sensors (can't
    remember the correct terminology) -- no cost, owner realignment
    * 12v battery getting very weak, probably ~12v vice ~12.8+ when
    new. 12v battery service life is ~4 years -- ~$160 replacement
     
    #10 Rokeby, Jan 26, 2010
  11. CharlesJ

    CharlesJ Member

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    It's even better than that. Her 2005 is doing this magic trick;):D
     
    #11 CharlesJ, Jan 26, 2010
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