Strange fillup

If he meant that he adds gas until the tank cost is in whole dollars, then it WOULD affect mpg. Putting in more gas for a fixed mile duration will change the mpg.

 

I'm curious about how people are calculating MPG, and coming up with wildly different numbers. I average my MPG calculations out over several fill ups.

I fill to the click, and take the nozzle out and put it on the pump. Topping off wastes gas, may damage the emissions system, and spews smog causing hydrocarbons into the air. I can't imagine someone socially concious enough to be concerned about their mileage spoiling the environment this way. Clubbing a baby seal to death is probably more rewarding!

I take the receipt and write the ODO mileage on it. I average out the mileage over several tankfuls. I only have 4 tank fulls in my spreadsheet so far, but my mileage is very, very close to what the MFD has given me over time ... 49 mpg. I have long suspected that those that claim the computer isn't accurate are simply doing it wrong; human error is much more plausible than computer error in this case.

Why don't I have "49.235435 MPG"? Because nothing after that decimal point matters ... its needless precision.

 

This fill up thing bugs me. There really is no way to accurately tell what your MPG is if you don't know that the amount of gas you put in gets to the same level each time. The only way I can think of to get an accurate read on your true MPG in comparsion to the MFD indicated is to run the Prii out of gas and carry a 5 gallon can of gas around with you. Do that a minimum of 3 times and average it out. Anyone see a flaw in that method?

Wildkow

 

You can not get to the same level in the tank and expect the amount of gas to match ever!
The bladder shrinks in the cold and won't stretch as much.

I always try to fill to the brim with gas and ignore all these warnings about the filter,etc.

My last fill up I finally gave up after 100 or so clicks and the tank was not full. Just got tired.
And the gauge never read full either!

In summer I have filled to the point I see gas no trouble with few clicks and had over 12.5 gal go in.
Then the gauge goes to full and stays for over 180 miles.

Same technique, but very different amounts of gas going into the tank.

 

This raises a concern for the folks that live in mandatory full service states like New Jersey. The service station guys always round up to the nearest dollar for cash transactions to make easy change for the "yuppie food stamps" ($20 bills). At the current gas prices, it doesn't amount to a lot of gas, but it could be as much as a third to half of a gallon. Could that be a problem?

I suppose I could tell them not to top off, but I'd better be jangling a handful of change in front of the guy when I ask...that is, if the guy even understands English (seriously, not a safe bet).

- Doug
(on the waiting list for a 2006--"only" 4 to 6 months left to wait)