i've filled gas 4 or 5 or 6 times on the H2 now, and each time it has required only 25-26 gallons despite the "low-fuel" warnings going off, and my range down to 15-20 miles. After filling, my range is typically 380-395 miles.

So unless the fuel/range/mileage computer is set to leave ALOT of gas in the tank as a reserve, or i have a smaller tank.

theories?

 

i'd say it's the computer playing it safe. i've put 30 in mine before, but usually don't let it get down to where the light comes on. not good to run an injected engine empty.

 

Definitely playing it safe, I think a lot of hummer owners would get pretty riled up if they would be standing on the side of the road 15 minutes after the warning light went on. Judging on how much you said you could put in your tank you have approximately 6 gallons left, which should be enough to get you somewhere.

 

Keep in mind the capacity of a tank is the total volume it holds. The safe full liguid capacity is never more then 90%-95%. This is needed for expansion room. After you subtract that off of the total, you cant forget about the unuseable abount left in the tank. This amount can vary depending on how it is installed and where the pick up is located. In small aircraft it can be as little as 1.5 gallons, and I'd figure something around there for cars as well. So, if your total capacity is 32 gal, your safe liquid capacity is about 28.8-30.4. After your unuseable amount, you are down somewhere around 27-28 gallons. This fits well with how much you have put in. Any time you can squeeze more in you are either overfilling the safe full capacity, or the tempreture of the fuel is warmer then standard and you are actually geting less volume per metered gallon.

 

Well put Linus..

I heard that if you fill up your tank tip top full in the cold of winter and say only drive a block or so to get home and then park in a nice warm garage, you could wake up the next morning with a little fuel on the floor..any truth to that?

 

It is possible, but you would have to fill it all the way up, and the gas would have to be extremely cold. The gas would also most likely have to be in an above ground tank so the tempreture can be signifiacntly lower then standard (59 deg F). In ground tanks do a good job of keeping the fuel at a reasonable temp, somewhere in the 50's. They aren't typically burried very deep, the stick I use to measure the fuel level is only about 14 feet long or so, and it goes all the way to the bottem. Being close to the surface and filled with cold air will also help lower the fuel temp, but it has to be really cold for a long time for the fuel to get cold enough to expand enough to spill out of your vehicle once you put it in your warm garage. Also the newer fuel systems are sealed better to prevent vapor loss, so that will make it more difficult to have a tempreture caused spill.

 

thanks guys.

i'm probabyl doomed to test this the hard way...