Fuel tank top off is bad. I'm now a believer.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bbald123, Feb 1, 2008.

  1. diamondlarry

    diamondlarry EPA MPG #'s killer

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    I think you'll be fine. There probably would have been a warning light or two by now if it had done anything harmful.
     
  2. morpheusx

    morpheusx Professor Chaos

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    I would have been pissed I would have made them give me 10 or 15 bucks just for a car wash too.
     
  3. R_Ann

    R_Ann New Member

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    Thank you sooo much. I remember "glancing" at this thread before this ever happened - but "knew" it was bad to top off the tank. Then when I read the post I freaked. Now I can breathe (in and out).
    (Yeah - I prob wasted another couple of bucks driving around that morning looking for a car wash near work since I don't work local I don't know where anything is - found one - but it wasn't opened yet - too early). Not a good start to day. If I had to do a service call on this I was going to take the bill in.
    Ok - breathe again.
    Whew.
    Thanks again.
     
  4. hobbit

    hobbit Senior Member

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    ...and there goes about 50 prius-years of HC emissions into the
    sparkling NJ air, because I'm sure those numbnuts just let it
    sit there and evaporate.
    .
    _H*
     
  5. R_Ann

    R_Ann New Member

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    ok - I'm going to be paramoid - but now at 300 miles and still only 1 "tick' down from totally full mark. (You know this would be something a normal person would be shouting gleefully about but in this situation...)
    Should I be calling the dealership for service for something to be reset? or is this going to reset itself? How am I going to know when I'm "empty"? (I know I'm not going to get like 1000 miles on this tank)
     
  6. diamondlarry

    diamondlarry EPA MPG #'s killer

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    I wouldn't be real concerned. I've had several tanks where the first "tick" didn't go away until the 300 or more mark.
     
  7. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    R ann. i am so sorry to hear what happened to you. Oregon is the only other "full service" state i know of and its that reason i avoid getting gas there at all costs.

    i dont blame you for being upset, i would be livid!! for one thing, i doubt that $7 covers even your gas expense much less the damage to the Pri's exterior.

    as far as damage to the fuel storage system. you are probably ok. the system is designed to take some abuse. only when repeated top offs occur will issues arise.
     
  8. R_Ann

    R_Ann New Member

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    so will the ticks just all of a sudden just "drop" when it gets near empty or do I do I guage by my last tank full (about 475)?
    (Sorry for all the questions, just don't want to do something harmful). I did (being female I guess) open up the gas cap and look inside to see if that would do any good.:rolleyes: (And no - I'm not blonde).
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Its reasonable for you to be cautious until you can observe whether your fuel gauge has returned to normal behavior. I suggest that you refuel after 400 miles have elapsed and see how many gallons you need.
     
  10. R_Ann

    R_Ann New Member

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    2 'pips' down now. But I think I will fill at 400. And you can bet I'm going to be standing right there waiting for that thing to click off. (Like it not NJ Laws - HUH!)
     
  11. PriAva

    PriAva New Member

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    I'm not sure if this situation has been addressed here or not. My wife filled up yesterday. I had told her to be sure and stop putting gas in after the pump clicked off, and to put the gas in at the slow rate if necessary to prevent premature click-off. She got home and said that when she stopped to fill up, the gas gauge had two pips left, and we had been a little over 300 miles since the last fill-up. She said the pump started shutting off after only a couple of gallons. She tried filling at the slowest rate and it continued to shut off. She knew it wasn't full, so she kept putting gas in, off and on. When it shut off at about 7.5 gals, she stopped. She came home hoping she hadn't "ruined" something. This is probably a situation that is not uncommon. I have experienced it before on our other cars, but was not as concerned about over-filling as I am now with what I have read about the Prius. Is this a problem that was peculiar to this pump? She asked if she should have gone to another pump. I said it might have been worth a try. Anyone else experience something like this?
     
  12. Voidvoice

    Voidvoice New Member

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    After reading this thread. I begin to understand better. Before I was scracthing my head, how Toyota design a car that spill out fuel when refueling.
    See if i understand the reason. First people try to put in more after the "click". Im curious why people not stop fueling when it "click" ? because it doesnt indicate the tank is full like normal car?

    Another reason is even stranger to me, people dont turn off their car when fueling?

    Perhaps people shouldnt have to worry too much if they just do the normal thing, stop fueling when you hear the "click" and turn off your car.

    Am I right?
     
  13. JimTheEngr

    JimTheEngr Junior Member

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    I am a new Prius owner (February 1, 2008) and I have a LOT to learn about this!

    Overfilling: it has been my habit to fill the gas tank carefully until I can see the fuel level in the filler pipe. This lets me verify that I have added a "precise" amount of gasoline since the last fill, and I know how far I have driven (within a mile), so I can calculate the miles per gallon. (Hey - I'm an engineer! see Dilbert comic strips...)

    Apparently, with a "variable size" gas tank, that no longer works. I guess I'll need to rely on the displayed MPG and use that to calculate approximately how much gas should go into the tank. That should guard against an early shutoff.

    I do have another question - once the bottom tick on the fuel gauge starts blinking, how much gas is left? I've been noting the odometer miles when it starts blinking. At some point, I'll bring along extra gas and run the tank dry and note the mileage. I can then add the extra gas and drive to a gas station.

    I understand that I am not supposed to drive the car without gas, even though the battery and electric motor SHOULD carry me a few miles (how many?) at low speed (what maximum speed?). Is it possible to make some change so that one COULD drive electric only?

    - Jim
     
  14. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Hi Jim,

    You might consider getting the maintenance manuals. Haynes has come out with one and I understand another 3d party manual is soon coming out. However, I went with the Toyota paper manuals, ~$300, and think it is the best start. They do show up on Ebay from time to time.
    The low emissions rating is due to a fairly complex and sophisticated vapor trap system that uses the space around the bladder in the tank. If you ever 'poison' this space from over filling, you'll get a master warning light and replacing the tank can be pretty expensive, ~$1k. I believe the consensus is no more than the second click is safe.

    I would suggest using the displayed MPG for specific experiments. The fuel gauge is adequate to avoid running out of gas. As for mileage calculations, any individual tank variance averages out over a couple of fill-ups.

    I've done this over two dozen times but my car is well past warranty and I have a scan tool that can clear any error codes (as if they matter now.) Until your warranties run out, Toyota is able to read out error codes including those that show you've run out of gas. Some Toyota service centers will use "running out of gas" to avoid a warranty repair. But excessive driving on traction battery after running out of gas is a real risk.

    There have been various reports of going a mile or so at high speeds. Personally, I prefer to be gentler on my traction battery but it is your car. IMHO, the best answer is to find the first safe place to park and use the one gallon, spare can you put in car when the low fuel alarm started.

    There is an EV modification that allows driving on just battery at low speeds, less than 30 mph, for a mile or so. Search for "Prius EV" and you'll find a wealth of information.

    GOOD LUCK!
    Bob Wilson
     
  15. kathyb

    kathyb New Member

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    I think I remember reading that premature clicking off of the gas pump could be due to fuel quickly entering the tank. Which leads to air pocket? I've taken to slowly refueling, pulling the nozzle out waiting a couple of seconds and continue refueling. The fuel tank only holds 11 gallons so if your aware of how many boxes are empty you can pretty much know how much fuel you need.
     
  16. LenS

    LenS New Member

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    Very good thread!!!

    Yes, I have ALWAYS topped off.

    This will take a different mind set. I am used to our van that gets 15.22mpg (78,000 mile average) and "only" has a 31 gal. tank for a maximum range of 471 miles. That has a 'simple' steel gas tank and the mileage varies from 14.5mpg to 16.3mpg when I use 2,500 miles of driving to generate the average economy.

    The Prius with a 12 gallon tank and getting about 50 mpg will have a maximum range of about 600 miles. So who really cares if there is 11 gallons or 12 gallons or 12.5 gallons in the tank. I still will not be stopping at a filling station very often.

    Now my new Prius with the bladder design and the fill errors designed into it means that individual fill ups really are meaningless. I will have to trust the vehicle computer for fuel economy until I at last get 10,000 miles of fill ups measure fuel economy with.

    Mine also spit up the first and only time I have filled it. I must have put 1/4 of a cup of gasoline into the air. I will fill it on a lower fill rate next time and try not to "overfill" it.
     
  17. berinker

    berinker New Member

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    Do you people think that Toyota engineers
    did not anticipate topping off? I have ran my
    2004 one gallon over the initial click-off point
    and never had a problem. That was after the
    very first fill-up with a very slow pump and
    it spit back at me when I removed the nozzle.
    Bud
     
  18. xsmatt81

    xsmatt81 non-AARP Member

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    when i first bought the car i topped it off, but not to the point where it would spew out of the car, so far no problems. But absolutely dont do it. Anymore i dont top off, once it clicks off from auto, i just pull once and that's it..

    so far everything has been fine, i normally get about 10 gallons in right now during these hotter months when it's cold about 7-8
     
  19. freshmtt

    freshmtt Dachshund Addict

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    IN the past I have never really topped off a tank where I waited until the fuel was coming out of the gas tank, my version of topping off is just pumping after the first click until I round out the cost on the pump. I'm kinda neurotic like that, I hate putting $23.72 in my checkbook, so I will pump until I round it out to an even $24.00, I don't really consider this topping off. But since I bought the Prius I don't even do this anymore in fear I will ruin something. So I just round off the figure in my check book and end up with lots of little extra cents here and there in my account, which is kinda cool to have hidden money in your checking account, at some point it will all add up.
     
  20. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Michelle,

    I am like you, to the extent that I like to pump gas to reach the next whole $. Considering that gasoline costs > $4 per gallon, this means that you are only adding <= 0.25 gallon after the first click-off, so no worries! My guess is that there is probably 1.5 - 2 gallons of "headroom" after the first click-off, if the pump is acting normally.
     
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