NO fix for Prius Gas Tank Filling Up Issues

[dar]

I do understand that the tank is rated at 11.9 gallons. I know that I will never get 11.9 gallons of gas in the car, that is not my concern. My concern is not knowing how many gallons of gas are in the tank to even guess a driving range.

What I base my fill ups on are the actual miles I have driven at about 45mpg. My Prius gets at best, around 48mpg. The first instance of this showed is would have gotten nearly 56, I was excited but a little concerned. The next fillup took less than 2 gallons and I drove 132 miles.

When the gas tank stops filling the car, it shows that I would be getting unrealistic gas mileage - over 55 on most fill ups. I use the slowest automatic on the pump and it still clicks off way too early.

I assure each of you that I am not over estimating the number of instances ... it has been every fill up since I hit 5000 miles on the car. At this point, since there is not fix ... I plan to fill up at what shows to be a 1/2 tank or 200 miles driven ...

Again, I thank everyone for their comments. I find this to be the strangest gas tank situation I have every encountered after owning over 2 dozen cars of different makes and models. I like the fuel economy, but I am not certain enough to keep dealing with the problem ... I will try a while longer!

[miscrms]

I don't understand your problem at all. Maybe you can go back and try to describe what you are actually seeing.

You always know at a minimum how much fuel is in the tank, because you just put it there. You always know when the tank is getting low, because the last pip blinks and the MFD says add fuel. When the pip blinks, I fill it up. Due to the bladder this can be ~8-9.5 gallons depending on temperature, fill speed, pump sensitivity etc. I assume that there was no fuel left in the tank (even though I know there is some) and just calculate my range based on how much I actually put in at a reasonable mileage (~50mpg usually for me, maybe 48 on a road trip). Normally I just don't worry about it and just fill up when the pip starts blinking. If I need to estimate a partial tank, I calculate using 11 pips, as the Prius gauge seems to peg off the top for a pip or so (like most gas gauges). The variability is a minor nuisance but IMHO its a small price to pay for the vast improvement in evaporative emissions.

I'm not really sure what you are trying to accomplish by filling up at 1/2 tank or 200 miles. Has your car ever run out of gas with the gauge showing something more than empty? If so you either need you inclination sensors reset or your tank float replaced. If not, I'm not sure why you are so uncertain about how much gas you have.

I'm also not sure why everyone seems to think just because the Prius has a 10 bar gas gauge that its actually any more accurate than a traditional needle gauge. Last week on my subaru the fuel light came on even though I thought I still had 1/4 tank. My wife had run out of gas just after the light came on a year or so ago, so I went right in and filled it up. It only took ~10 gallons into a 16 gallon tank, so I tried to top it up and barfed gas all over the place. Starting the car up it read completely full. Thats the equivalent of a 7-10.75 gallon uncertainty in a Prius. On my Land Rover I used to see as much as an 1/8 tank change in the needle from parking it at night to starting it up the next morning. On the Land Rover I've had the tank range be anything from 250 to 330 miles (on 23 gallons of Premium, ouch!). Thats the equivalent of an 8-10.5 gallon variability in a Prius, and those vehicles don't have the added complexity of the bladder to deal with.

Rob

[M. Oiseau]

What the OP describes happened to me several times (maybe 4-5 times out of 137 fill-ups), but I know, more or less, how much should go in, so I just manually fill very slowly until the nozzle clicks off. I've never spilled gas doing this and the car has never barfed gas.

I'm not sure the criticality of the numbers for the OP unless gas will be unavailable and fill-ups must be planned. The tank's either full or it's not.

[freshmtt]

I don't have any issues with the tank so far, I have owned the car for almost 2 months now and I think the most I ever put in was 8 gallons when it was down to 2 pips.

I don't know if you can ever really know how much a gas tank holds. I just recently found out that my traded in SUV, the Saturn VUE is supposed to hold 16 gallons of gas. Well, in the 3 years that I owned that SUV, the most I was ever able to put into that tank was 12 gallons, and that was when the gas gauge was down to empty and the light was blinking. I don't think the SUV holds 4 gallon reserve when your light start blinking telling you you are almost empty.... So, I don't know how much my VUE tank ever really held. I know for certain I was never able to put more than 12 gallons in.

But why should this issue with the Prius tank be such an issue?, I just don't get it, I fill my tank when the gas gauge tells me the tank is low, I know to fill it around 2 pips, so are there people that only fill their tank according to their mileage??, I don't, I watch the gas gauge and when it gets low, I fill it up.. I have never heard of anyone running out of gas at 2 or 3 pips. So just fill it up when it reaches that point. What does it matter really if the tank holds 11.9 gallons or only 7 gallons of gas, as long as the gas gauge appears to be working properly and goes down from 10 pips to 2 pips or 1 pip, that should be enough warning to fill the tank when the pips get too low.

I'm just not understanding why some have such a problem with this? Just fill up when the pips get low,, it is not like there is no gas gauge or are people just trying to say that they don't have to fill up for a month? I don't think too many of us live in such a rural area that it would be over 50 miles or so to a gas station and I don't think that the gas gauge works that badly that you would have to worry about registering a half tank and then no gas within a 50 mile radius.

[racerbob]

Originally Posted by dar

I contacted Toyota Corporate about recent challenges I have had trying to fill my gas tank. It is nearly impossible to get anywhere near a full tank of gas in this 2008 Prius. What is most interesting and disturbing about this issue is that Toyota noted this IS an issue and that there is NO fix for the problem. Here is the response from Toyota Corporate:


Dear Ms. :
We apologize with your dissatisfaction with the fuel tank bladder in your 2008 Prius.
As your Case Manager explained to you, this is the design of the fuel tank and there is no repair available to change the design.
We appreciate you taking the time to let us know of your dissatisfaction with the fuel tank bladder because the only way we know what our customers are looking for is when they tell us, as you have. We try to scope our customers out in advance, by researching the market, conducting interviews, surveys, focus groups and doing our homework, but there's no better source than a Toyota owner who takes the time to tell us like it is.
We can't guarantee that a change would be made, but if it were, it would be driven by just this sort of honest communication.
We have documented your email at our National Headquarters under file #. If we can be of further assistance, please feel free to contact us.
Sincerely,

Toyota Customer Experience

I have read that many other owners have the same challenge. I have talked with Toyota technicians who are frustrated that they cannot take care of this issue ... which gets worse in the winter .... as the bladder collapses and the cold weather keeps theh bladder from expanded back to the 11.9 gallon size!

For those of you that are not having issues or do not mind this ... great! I for one really need to know if "full" means 6 gallons or 10 ... can I drive 300 miles or 400 miles on a tank??? Overall, it is a nice car ... it is not a safe long distance drive car ... Consumer Reports was VERY interested in this design flaw ...

Just learn to live with it and enjoy the other 200 good features of the car. Nothing is perfect. It is a good thing that many are making Toyota aware of their dissatisfaction with this problem. They have known about it before the 04 model hit the streets. Maybe they will make a major change in the 2010 model.

[PriusSport]

A good estimate of partial filling is to compare the computer mpg since the last fillup with the calculated mpg based on the trip odometer and gallons filled. My first fillup on the car at 150 miles, the computer read 48 mpg vs the calculated 65 mpg. Assuming the computer was correct, the tank was .8 gallons short of fillup due to the bladder? Maybe. But maybe the dealer filled the tank more than I did using the auto-stop on gas pump. We'll see what happens next fillup.

[Alolio]

Sorry to hear you've had so much trouble. That happened to me once at a Sam's Club gas station. I could only add 7 gallons, so I checked another pump. Same story. So I drove down the street and added the final two gallons from another station. I chalked it up to wierd pumps, but the last time I went to Sam's for gas, it didn't happen... I'll open an X-File on that one, I guess...

[tkil]

Originally Posted by freshmtt

I'm just not understanding why some have such a problem with this? Just fill up when the pips get low,, it is not like there is no gas gauge or are people just trying to say that they don't have to fill up for a month? I don't think too many of us live in such a rural area that it would be over 50 miles or so to a gas station and I don't think that the gas gauge works that badly that you would have to worry about registering a half tank and then no gas within a 50 mile radius.

One might not live in such a rural area, but I (for one) often drive through them. Knowing whether I've got 50 more miles in the tank, or 200, can make a difference in how often I stop -- and every stop does take extra time and MPG hit. (Not as much time as running out of gas in the middle of nowhere, granted, but there have been more than a few times I've wanted a reliable "miles remaining" calculation on the Prius.)

[dar]

Sorry that I have not explained my issue better.

Each time I "fill" the tank ... the gauge shows that the tank is "full". My issue is that I do not know if full is 10 gallons or 6 gallons in the tank ... which is quite a difference in range of travel.

Thinking that I have 10 gallons, I could drive easily 450 miles at 45mpg. If full was only 6 gallons at 45 mpg, I would run out of gas at less than 300 miles. I understand the bladder causes the gauge to show full at 6, 7 or 8 gallons, as well as a truly full tank of gas.

Again running around in town or areas where gas stations are open 24/7 ... no issue. On long road trips late into the evening in areas where gas is not available 24/7 ... not knowing if you can go 300 miles or 400 miles ... is a concern. I bought this as a road trip car ...

I will keep an eye out on this site and on my fueling issue. I know that I am NOT the only Prius owner with this problem ... it is noted on several other sites. Most owners and Toyota appear to accept that filling up 6-7 gallons as just fine ... I guess that I am too scared of running out of gas to like this much ...

Thanks again everyone for trying to assure me that this is not a big issue ... :-)

[lwnboy]

I have a new 08 and have had this issue a couple of times. From what I can tell, for me, it has to do with the filling station and the speed at which the tank is filled.