OK, so I ran out of gas in my 2008 and am feeling pretty dumb and frustrated . I had been filling up when the last pip started blinking, and was only getting about 9 gallons into the tank. Having checked several places and found that the tank capacity is 11.9 gallons, I wanted to see if I could run it down a little lower before refilling. Seeing as how I was getting 45 MPG and the tank is 11.9 gallons, I figured I should be fine up to at least 490-500 miles, but I ran out at 471 (!?!??!?) Can someone explain this? Is the tank not really 11.9 gal (yes, I know about the bladder)? Or is the milage totally incorrect?? Please help.

Thanks.

--Fuzz

 

I've run out of gas over three dozen times, deliberately, in my NHW11, 2003 Prius. I've found the usable gas to be ~11.3 gallons +/- 0.2 gallons. But when I run out of gas, I have a one gallon spare can in my trunk.

As for the 'guess' gauge, if it blinks, I put the spare can in the trunk. After the blinkin' light starts, I've been surprised with as little as 20 and as high as 130 miles but the average is closer to 65 miles before the gas finally runs out.

Bob Wilson

 

Please understand your 2004-2008 NHW-20 Prius before complain it.
The NHW-20 Prius has a fuel tank system with bladder, which means the capacity is not always 11.9 gallons.
The owners manual clearly says "The fuel tank capacity is decreased at low ambient temperature".
You'll be only sure you have at least 9 gallons if you put 9 gallons, that's all.

The computer mileage has a few percent of errors. The variation is different vehicle by vehicle. You have to know your own variation of your displayed mileage.

Ken@Japan

 

Well, by my calculation my tank is only holding about 10.4 gallons. Could this be correct? (270/45=10.4) Does anyone know how much difference the bladder makes? What is the point of the bladder, anyway?

Thanks.

 

471/45=10.47 plus/minus 3%.
Depends on ambient temperature.
http://priuschat.com/forums/prius-te...r-exposed.html

Ken@Japan

 

"DOH!"

 

My '06's milage is getting over the board. The relationship between the display and the, "guess gauge" is increasingly random.

So, to protect myself, when that thingee starts blinking, I'm looking for a gas station. If it's in the evening I'll park it until the morning, otherwise any station will do.

In short, you're too rational. Look at the whole thing (display, gas gauge, fill-up) look at as magic.

 

The bladder capacity definitely depends on temperature.
In the colorado winters, most fillups are around 8-9 gallons
In the summer, it's ~10 gallons. 11.0 is the most I've ever put in.

Also, it may help to fill at a slower rate (but don't top off - bad for the air and for the car).