Hi. Does anybody know, or have a guess, how the car estimates remaining miles based on fuel remaining in the tank? Sometimes when I fill it, it says something like 300, but then after driving for a while it's a lot higher.

 

My guess is that there is a sensor set off when fuel gets to a specific level, say 3 gallons /10 litres left. The car has been tracking you mpg, so (residual gallons) * miles/gal = number of miles left.

Of course this may not be accurate if your driving behaviour changes, such as you go hooligan, or conversely do highway driving when you did not previously. I find the fuel mileage numbers a bit optimistic to begin with.

 

Yes they are. I pulled into a station as soon as my last bar disappeared, and range hit 0. Was only able to put in 9.7 ish gallons before the the pump stopped to prevent topping off. I don't know the measurement of how much would be left when those stop to prevent topping off. I have a 10.6 G tank in Honda Fit 2015, so you can draw some conclusions.

 

Fuel foams so the auto shut off on the pump stops it long before the tank is full. Last time I filled up I stopped at the auto shut off then was able to add around 2 more gallons by fueling slowly. Which I don't recommend because if you fill slowly the auto shut off doesn't work and you'll spill fuel.

But what I'm wondering is- how does it get a number to use for expected mileage?

 

It's adaptive, which means it changes on the fly according to how much fuel you have and the way you drive. For example, I was doing a road trip last summer and was in western Missouri when I decided that I wanted to fill up next at the Costco in Tulsa. My Miles To Empty readout showed I would run out of gas about 45 miles before I hit Tulsa. I was going about 80 mph on the interstate and had maybe a half tank so I kicked it down to 65 mph using the cruise control. For a long time my MTE readout did not change and even rose slightly but it still didn't seem to be enough. So I kicked it down again to 53 mph. It was kind of scary because I was the slowest thing on the road and even the grandmas were passing me (at one point I was followed by a cop and thought maybe I'd get pulled over for going so slow -- I was above the minimum but not by much -- before he got off somewhere around Joplin). But my MTE readout stayed static then started rising and eventually it matched the distance to Costco on my smartphone nav app. I kept at it and eventually rolled into the Costco with 12 miles to spare.

 

Computer assumes full tank is 10.5 gallons. Give or take the following calculation...

Range= (10.5 gal - miles driven/average mpg) x (average mpg). It is not rocket science.
For example miles driven 225 miles, average mpg= 42.5, then the range is (10.5-225/42.5) x 42.5 = 221 miles. Do your own calculation using the information from the gauge to verify the range shown in the gauge.

I have been consistently able to put in over 11.1 gallons of gas without spilling. Folks, it is not that difficult to fill the tank completely. The last fill was 11.223 gallons. When I am local, I fill the tank when no bar is showing. Previous fills in gallons: 11.163 11.156 11.162 10.990 10.892 11.223

A good estimate to when you should fill the tank is take the average mpg and multiply it by 10. Take that number and subtract the number of miles you have gone (hint: check your trip ODO).

 

I've heard this before. When my car was newer I'd shut it off for maybe 15-20 secs in the middle of refueling to let things settle down a bit. But I never really noticed any real difference in the amount I can get into the tank before the auto shutoff kicks in so at some point I just quit doing that. I've read conflicting stories about topping it off (filter saturation isn't supposed to be good) so I've always gone the cautious route. Just a scared-y cat, I guess.