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Shrinking Gas Tank

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Larry Lininger, Nov 20, 2015.

  1. Larry Lininger

    Larry Lininger Junior Member

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    I bought a used Prius a year ago. I love it, but I've never gotten more than 395 miles to a tank of gas. (Thinking the fuel guage was wrong, I kept driving and ran out of gas.)

    I've never been able to pump more than 9 gallons. My book says I have a 12-gallon tank, and I get over 40 mpg, so something is amiss.

    I filled up two days ago with only 310 miles on the odometer and could pump on 7.8 gallons while my last fuel bar was blinking.

    Has anyone else experienced this? If so, what kind of repair do I need?

    Thanks.
    First time poster.

    Larry L
     
  2. bisco

    bisco cookie crumbler

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    welcome! your tank has a rubber bladder inside of it. under 'normal' conditions, you have about 2 safety gallons left when the last bar starts blinking.

    as the weather gets colder, the bladder will not accept as much fuel. for tips, see other threads on 'the fuel tank bladder' in the gen II forum. all the best!(y)
     
  3. techntrek

    techntrek Member

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    To keep the bladder's shape so it will accept more fuel (usually), the rule of thumb is to refill when there are two dots/bars left. Yes it means you are effectively using less of its capacity but you are sure to have a reserve when you need it.
     
  4. 48mpg

    48mpg Member

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    I fill up every 300 to 350 miles with 2 bars showing, when filling the car you can get almost a gallon after the pump shuts off the first time by pulling the nozzle out half way and turning it side ways than slowly filling.. this allows more air out of the bladder but don't do it all the time as it can flood the emissions canister (I forget the correct name for it).

    I have gone 160 miles before it dropped off full than it drops like a rock over the next 150 miles..
    running out of gas will burn up your fuel pump so don't push your luck..unless you want to spend about $1000 on a new one

    I have never seen a prius get the 500 miles a tank or constant 50 mpg they said it would..I can push mine to 48 mpg but over the tank of gas its more like 44 and Im happy with that on a 10 year old car with high miles..

    read the articles on tire inflation to bump up the MPG a little more..
     
    #4 48mpg, Nov 21, 2015
    Last edited: Nov 21, 2015
  5. bisco

    bisco cookie crumbler

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    there are more than a few 'tricks' to increasing mpg's, and thus tank distance. but driving style is probably the biggest.
     
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  6. wjtracy

    wjtracy Senior Member

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    normal behavior...as stated we with Gen2 have a flexible "guess" tank.
    7.8 gal typical for colder weather fill-up.

    The only time we get >400 miles (never got 500) is in summer doing a long drive on the highway getting 50+ MPG. Most we ever got is 485 miles and that's on long trips in summer.

    You don't want to run out of fuel as Gen2 allows the battery to run down when you do that. You don't want to run the battery down to zero charge because that kills it.

    When you get a really good fill up, you get about 150-160 miles or so on the first pip (adjusted to 50 MPG). usually that does not happen either as the tank tends to not want to get filled like that.
     
  7. JC91006

    JC91006 Senior Member

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    The math usually works out regardless if you are able to squeeze 10 gallons in or 7 gallons in. The mpg will pretty much be the same.
     
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  8. WilDavis

    WilDavis Senior Member

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    I keep accurate records of how much is put into the tank, and how many miles the car is driven. It's maths FGS, so what's the big deal?:confused:
     
  9. techntrek

    techntrek Member

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    Never heard of that.

    Not true. The Prius will allow you to limp up to 2 miles on the battery after it runs out of gas. No damage to the fuel pump.

    Ours is 7 years old and I still regularly get 52 mpg.
     
  10. wjtracy

    wjtracy Senior Member

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    Just noticed we are at 45 miles on this tank, and the first pip is gone already. I think that is 100-miles deficit right there. Most we can expect on this tank is probably 350 miles.
     
  11. WilDavis

    WilDavis Senior Member

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    Since Jan 2014, average of 84 fill-ups = 5.88 gallons per fill-up, and 267 miles, and the maximum is 9.16 gallons over 449 miles. I've never seen the flashing last-segment, and usually fill between ¼ and ½ on the gas gauge, for reasons mentioned above!:)
     
  12. LarryYT

    LarryYT New Member

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    What increases mpg?
     
  13. WilDavis

    WilDavis Senior Member

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    Search this board for pulse & glide, also youtube has many, many videos describing the technique! Welcome to PriusChat! :)
     
  14. bisco

    bisco cookie crumbler

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    increase your tyres pressure to 42/40 f/r, make sure your oil level is midway on the dipstick, drive the speed limit. accelerate briskly to a little above the speed limit (pulse), then release the gas pedal and press down just enough to get no arrows flowing on the power meter (glide). make sure your air filter is clean and when you reach 100,000miles, start thinking about extraordinary maintenance like plugs, throttle body, mac sensor and etc.
    in winter try to bundle your trips and drive to the furthest one first, then work your way back home. whoops, you're in az.:cool: that's all i can think of, but others will chime in, and as wildavis mentions above, plenty of mpg threads.
     
  15. WilDavis

    WilDavis Senior Member

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    I haven't come across the "oil-level mid-way" one, care to elaborate? (…please!)
     
  16. bisco

    bisco cookie crumbler

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    happy place. you don't want it above the max line, but midway is even better with less total internal pressure.
     
  17. WilDavis

    WilDavis Senior Member

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    Makes sense! Thanks!
     
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  18. fuzzy1

    fuzzy1 Senior Member

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    #18 fuzzy1, Nov 21, 2015
    Last edited: Nov 21, 2015
  19. Mendel Leisk

    Mendel Leisk Senior Member

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    May not damage the fuel pump, but could run the hybrid battery's state of charge to fall to extreme low level.

    See post #6, third paragraph.
     
  20. techntrek

    techntrek Member

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    I have seen that quoted many times and I have never seen any proof. When I run my Prius as a generator (see the link in my sig), the computer never lets the battery get below 200 volts - at that point the engine starts. It would only make sense that if the computer knows the engine won't start when the battery is at 200 volts it would shut off the electric motors, too. There are so many protections built into the vehicle (traction control to protect the transmission, ground fault protection for the HV system, etc) I'm sure they thought of this situation and guarded against it.