I'm not sure if my gas station is scamming us, here's my story: Last time I filled the car, my Prius (07 blue package 2) told me I had ~52 mpg, but when I filled up, I calculated it to be ~48 mpg. I didn't think much of it because there is a lot of room for discrepancies. I just figured next time I fill my tank, my mileage should be better than my car tells me. Just today, I filled my tank and I got 11.431 gallons. This is weird on its own because I was just down to one tick and it wasn't even blinking. I should have had atleast 2 more gallons in the tank, but the Prius tank isn't that big. Also, my mileage this time was supposedly 51.4 mpg, but my calculated mileage (489 miles out of 11.431 gallons) is only 42.8. What's going on? Why is there such a big difference? I shouldn't be filling my tank this much...normally at 1 tick left w/o blinking, I only fill 9 gallons, maybe 10. Thanks for reading this long post. Please advise!
This is fairly normal behavior. Do a search for "bladder" or "guess gauge" and you'll see hosts of posts about the inaccuracy of the fuel gauge. The bottom line of all of them ... don't trust the displayed MPG to determine how far you can go on a tank of gas.
Whats weird is you've been a member for over a year and haven't stumbled upon the hundreds and I do mean hundreds of "guess gauge".."gas tank bladder" posts which describe your issues in extremely boring detail. But nice try blaming the gas station though. Inaccurate gas gauge questions made PriusChat what it is today. God bless 'em. Got a few days? Google: Toyota Prius Gas Gauge I dare you. :boxing:
I've read a lot about the bladder, but this seems super extreme. Also, I check my mileage 2 ways every time I get gas. I've never had such a big difference.
I agree... it does seem extreme. If you're thinking your gas station has calibrated their machines wrong, it wouldn't be so hard to check. Either go with a gallon container of some sort and see if 1 gallon of purchased gas fills the container as it should. I think I saw in one of those many bladder posts that the nice poster above so nicely reminded you about that there's a number to call if you think gas stations are shorting you, but I'm afraid I couldn't find the link. Maybe some other nice poster will point you in the direction, but I probably wouldn't take that step until I had confirmed it for myself by doing an actual test with a graded container. Good luck.
Gas station pumps can and are inaccurate. I've run out of gas in my SC400 4 times in 10 years. Each time, I managed to cram a maximum of 19 gallons in. Normally it's 18 to 18.5 meaning that I'd have 0.5 to 1.0 gallons left before running out of gas. Several months ago, I filled up at a gas station in Dinuba. The pump clicked off at 21 gallons. I went in and told a story to the clerk about how I once ran out of gas moments away from a gas station and managed to coast in. I explained that since I had run out of gas, I was able to put as much as 19 gallons into the tank. Blank stare. I then said but my tank just took 21 gallons and I didn't run out of gas. Interesting, isn't it? Blank stare. Since he still wasn't getting it, I came right out and told him that my tank doesn't hold 21 gallons. Blank stare. The meter on your pump is inaccurate. Oh no, it couldn't be. I reported it to the Weights and Measures commission in CA. That was one screwed up pump. I make sure to avoid that gas station every time now.
Thanks for your help nicer people How many gallons is the maximum that people have been able to put into the tank? This was another part of my concern. People on this forum say the tanks usable capacity is about 10 gallons. If I got almost 11.5 gallons without even being close to empty, that should imply there is something wrong with the meter, right?
There has been an occasion or two when I have been able to squeeze 11.5 gallons or so into mine like on an extremely hot day. Normally it is rare if I get more then about 9.5 gallons in it.
I can't recall ever filling above 11 gallons, even with the last pip blinking. But I've only had the car 1 year, so who knows. If you can narrow down your suspect gas station to the one station, I see it that you have two choices... either you just avoid that station because you suspect their pumps are calibrated wrong, or you report it (maybe confirm it for yourself first... I don't know if you have to have some kind of 'evidence' when you call the Weights and Measures people).
nah you don't need evidence, there supposed to inspect the pump annually anyway they do have an undercover fleet of vehicles that will purchase gas from random gas stations to make sure they don't cheat customers too maybe if you say something, they will check it out i know they have undercover vehicles, i am not sure if its a fleet tho, heh
i also agree you probably got a bad pump. in WA state, the inspection is once every 3 years and they are running an average of 10-18 months behind. a TV news team went undercover a few years back finding about 1 in 9 to be inaccurate and of the inaccurate pumps, they favored the station by a 5 to 1 margin. in 2005 i reported a pump to the weights and measure bureau for a tank i felt i was cheated on. after 6 months, i got a letter agreeing that "inaccuracies were detected but not enough to warrant further action"
I do an average of 450 to 480 on a tank of gas, and each and everytime I fill up, it takes 11.3...11.4 gallons of gas, and the most I can ever get is 41 to 43 mpg. So it's not your gas station that is ripping you off so don't worry about it. I never depend on what the MFD displays says, etc..etc.... I fill up...take out my calculator divide the miles by the amount of gallons I put in, and it has never ever been more than 43 mpg. And this is done by 8 tanks of gas, and I've done 2,386.6 miles and put in 57.81 gallons of gas which averages 41.283 mpg since I have owned my 2007 Prius Pkg. #4
OK, I filled up today... we had 460 miles on the tank and it took 9.6 gals. We were down to the last blinking pip, and had about 6 miles on it after it had started blinking. I checked my log, and the most we ever filled was 9.88 gallons. We average about 48 mpg and drive consistently.
Although we measure our gallons differently, the gas tank in the US Prius and the UK Prius I believe is the same in litres at 45 litres. Converted, this would give a max tank capacity of: Imperial Gallons 9.9 US Gallons 11.9 ...but that's without allowing for a bladder....
