I'm not understanding that. If my prius is sitting next to your prius and you got 5 gals left and I have 2 gals left (low indicator blinking), isn't that still the same temperature in the tank such as the outside air temperature, or air temperature plus heat emitted by vehicle, whatever that happens to be? Maybe you are just living in a freakin hot place dude, move north. Just kidding.
Yes, part of it is the hot climate, but keep in mind that in summer (anywhere) the more fluid (gasoline) there is in the tank, the more substance there is to absorb and dissipate the heat of the electric motor running the pump which is inside the tank. Add to that, in northern climates where humidity is a factor, there tends to be more condensation/moisture inside a fuel tank if you keep it low. This sparked (excuse the pun) a lot of discussion on a prior forum I belonged to until it happened to me. My fuel pump went out and it was $900 to replace it. All fuel pumps have a given lifetime, but you can help prolong it by using quality gasoline and not always running the tank to low or empty.
I'm a new Prius owner (metallic blue, about six weeks old) and I'll share my low gas indicator story I just had last night. So I was driving home from work (about 20 miles) and I had 1 bar left on the indicator. It said I had about 37 miles left on this bar. So I'm rushing to get home and find a gas station to fill up. I live in Bend, OR so for some reason there are like 2 gas stations open past 10 PM. I finally find a gas station and the indicator has already been flashing for about 10 miles. All of the sudden it went from 10 to fill up, to 0 to fill up... as I'm literally pulling up to the station for the attendant to fill up. I don't know how much I had until it would run out, but this was pretty crazy timing nevertheless. Has anyone else run into this issue before? I love my Prius though! Greatest car on the planet!
Unless you supplement this information with how many gallons it took to fill up your tank, I don't think you have given enough information to advise you. The tank holds a little more than 11 gallons, doesn't it? If you filled up with 8 or 9 gallons then you now know you really had quite a while before you actually ran out of gas. I am too chicken to actually run out of gas to see how long my light was on. In fact, I haven't even let my light go on yet, but I suspect it is just a matter of time.
Take a look at Bob Wilson's post on page 1 (he's done the experiment for you). ~ 2 gallons left when the last fuel "pip" starts blinking.
As the others have said - I tend to get just about 50 miles per pip, or just about 1 gallon per pip. The last pip starts to flash with about 20 "miles to empty" - or about 480 miles into the tank. When the last pip starts to flash, I have just about 2 gallons left in the tank. The last 2 gallons are "hidden" from the display - sort of a secret reserve. I'd personally prefer that when your car says you have 20 miles until it is empty - that you really do have about 20 miles until it is empty. However, that not being the case, it's nice that it is fairly consistent that you have 2 gallon left when the car says you are empty. After all - consistency is the hobgoblin of little minds - so I'm good with that. The only thing to be careful about - there is some terrain that you don't get anywhere near 50 MPG in - namely long uphill mountain stretches. I don't mind running the tank down on the flats, but am more careful in the mountains as I can't count on getting 100 miles on the "reserve".
My Distance To Empty display has also snapped from 5 or 10 to 0, skipping everything in between. ScanGaugeII can display an Xgauge fuel gauge reading to tenths of a gallon, see Adrian's spreadsheet. It reads about one gallon more than the dashboard display bars, but sloshes around a lot more. I've run down to 0.7 gallon on this display (and there should be nearly a gallon more beyond that) --but not all the way out as Bob Wilson has done for our benefit.
I am now convinced that Bob Wilson's Prius has about two gallons left when the last fuel pip starts blinking. I am not convinced that MY Prius has that. I am not sure I need to find out.
We call it a guess gage for a reason. Is gen 3 still a fuel bag? vs a tank. Must get all air out to get max amount of fuel in. Fill it up till pump goes off and then pull pump out, wait 30 seconds, put more fuel in and you might get another gallon in her. Do not run out of gas EVER if possible. E means Empty. Go get gas. Don't wait for alarm.
The Gen3 does not have a fuel bladder. I have never ran mine out of fuel but I have pulled into a gas station, a couple of times, just as the last pip started to blink and it takes about 10 gal to fill it, indicating it had about 2 gallons left.
According to a spreadsheet somewhere on this site (It's in Spanish, btw.), the "reserve" when the bars go away is about 6.5 liters (1.7 gallons). My inference from a number of posts and from various calculations is that the reserve is available, but is not counted in the dashboard "distance to empty" computation. I do know somebody who ran a Gen II completely out of gas. Nothing bad happened, except I had to bring her a couple of gallons in a can. (No, I am not related to her.)
