Miles until empty not adding up
Thread Starter
2018 FX4 2.7L Super Crew
Joined: Feb 2013
Posts: 316
Likes: 32
From: South of Detroit, Downriver.
Miles until empty not adding up
I have a 2018 XLT Super crew. 27 gallon tank. I filled up today until I could not fill it any more. I am averaging 21.1mpg right now. 27x21.1=569. How come when I turned the truck on it read only 506 miles until empty? What gives?
2024 F150 King Ranch
Joined: Jun 2009
Posts: 612
Likes: 67
From: Jacksonville, FL
You number is strange as I too get around 21 mpg but when I fill up mine it indicates slightly over 700 miles till empty.
5 Year Member
Joined: Mar 2009
Posts: 1,328
Likes: 535
From: The Great Midwest, aka, Flyover Country
I think the standard tank is 26 gal? Ford calculates the MTE that leaves a "reserve" of about 1/16th of a tank when the gauge reads E, so 26 gal x 15/16 = 24.37 gal x 21 MPG = 512 miles. Pretty close.
5 Year Member
Joined: Mar 2009
Posts: 1,328
Likes: 535
From: The Great Midwest, aka, Flyover Country
Thread Starter
2018 FX4 2.7L Super Crew
Joined: Feb 2013
Posts: 316
Likes: 32
From: South of Detroit, Downriver.
5 Year Member
Joined: Apr 2016
Posts: 3,677
Likes: 1,722
From: Georgia
Change the display screen and never look at the miles to empty readout. You are averaging 21.1 mpg overall, but over any 15-20 minute time span you could be getting 3 mpg, or 40 mpg. Yes, I've hit 40 mpg on a 30 mile stretch of all downhill mountain road. I don't know how often the computer updates the readout, but it isn't based on the 21.1 mpg average. It is based on the most recent fuel mileage and the miles to empty can change dramatically as driving conditions change.
I've been on flat interstate runs where I was getting 19-20 mpg and the display would show 600+ miles to empty. Then driving conditions changed and the miles to empty would drop by 200 miles. I've seen the reverse happen. When driving in conditions where fuel mileage was in the single digits the miles to empty was on 350. After getting back onto a road with more favorable conditions it jumped to over 450 miles.
The only display I concern myself with is the gallons used. I have a 36 gallon tank. When I've used 30 gallons I start looking for a fuel station. In the time I've owned the truck that display hasn't been off by more than 1/2 gallon. Usually within .2 or .3 gallons.
I've been on flat interstate runs where I was getting 19-20 mpg and the display would show 600+ miles to empty. Then driving conditions changed and the miles to empty would drop by 200 miles. I've seen the reverse happen. When driving in conditions where fuel mileage was in the single digits the miles to empty was on 350. After getting back onto a road with more favorable conditions it jumped to over 450 miles.
The only display I concern myself with is the gallons used. I have a 36 gallon tank. When I've used 30 gallons I start looking for a fuel station. In the time I've owned the truck that display hasn't been off by more than 1/2 gallon. Usually within .2 or .3 gallons.
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Senior Member
Joined: Dec 2016
Posts: 2,122
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From: Midwest USA
Is your 21.1mpg from the lie 'O meter or hand calculated?
Other than that the calculation could factor in your previous 'average' mpg driving habits over who knows how many past fill up's.
The manual also indicates its an approximate reading.
I personally don't pay any attention to that distance to E reading and i take the computer's mpg calculation with a grain of salt.
I watch the fuel gauge which is never below 1/4 of a tank.
Other than that the calculation could factor in your previous 'average' mpg driving habits over who knows how many past fill up's.
The manual also indicates its an approximate reading.
I personally don't pay any attention to that distance to E reading and i take the computer's mpg calculation with a grain of salt.
I watch the fuel gauge which is never below 1/4 of a tank.
