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Gallons used is that an average or total per trip?
I hand calculate my fuel logs, so I have always wondered why the "Gal used" isn't the same as what I'm pumping in the tank. I don't "double click" or try to over fill, I just set the handle and wait until it stops. While not a truly big deal, I'm just trying to understand the usefulness of this screen if the only thing I can use is the miles.
For example this says 18.6 Gallons, but I pumped 18.9, not a big deal, but I have noticed this goes up and down, never matching what I pump. This is actually the closet I've ever seen it, normally it is off by about a gallon.
Don't get me wrong, I'm not complaining about 22 mpg for a 5.0l supercrew (confirmed by hand calculations) I'm just curious about how this "gal used" works, like I said, not really a big deal, just curious.
It is the truck measuring the gas that was used. It will never match what you're able to put into the tank, based on varying shutoffs at different gas station pumps. You were within 1.6% and you're complaining?
My guess is the program calculating this using the fuel level sender to determine the number of gallons used. If you fill past the initial shutoff of the pump you are exceeding the fuel level sender's max range. This will give you a better mpg reading, though false, since the sender assumes 36 gallons even though your tank may have 36.5 or 37 gallons. The fact that you don't overfill your tank is the reason the gallons used is so close to what you refill your tank with. The same thing applies when your gauge reads E, there are 2 or 3 gallons remaining because the fuel level sensor is at it's minimum range limit. It's like a toilet level float. So the program just tracks the change in the fuel level sender in gallons and miles since the last reset. That's why it's not extremely accurate. Just my guess on how the Ford engineers did the programming. Nice MPG you have. KISS - Keep It Simple Stupid.
I try to always use the same gas pump at the same gas station, this limits pump errors from pump to pump from station to station. I always use a ScanGauge II (device which plugs into the OBD II port; provides real-time data on values such as actual coolant temp, actual alternator output, transmission fluid temp, etc and can check DTCs) which I've meticulously calibrated after quite a few fuel ups. Between the truck computer, the Scan Gauge, and the actual pump I'm about where you are. They're almost always within 0.5 gal used of each other, but there are times where it could be slightly outside that. If you are always within 0.3 I wouldn't even sweat it. Chalk it up to acceptable tolerances. (There might be times your fuel pump is drawing more or less fuel than commanded, your fuel pressure sensor might have errors during certain conditions of use, etc and this information may not make it to the fuel used calculator)
Fuel station pumps are supposed to be calibrated about once a year (IIRC) to a pretty small error late (something like less than a tablespoon amount). I'd trust the pump output more than what the computer says. The fuel companies stand to lose more on pumps than Ford has invested in their fuel economy calculations (which are at this point for our own knowledge and therefore these "error rates" mean diddly squat to them, my guess).
Edit - I've nerded up my fuel consumption calculations/tracking through the years because I like knowing the exact amount of fuel I have left in my tank. It's also out of curiosity since I was also a pilot for 13 years and fuel is life.
3/10 of a gallon error with a 36 gallon tank is pretty accurate. I've had my truck for almost 4 years and have only had it come out perfect a couple of times. But I've never been off by more than 1/2 gallon either. My F150 is pretty darn accurate with the fuel used, and my MPG readouts. Usually within 1/2 gallon used and within 1/2 MPG. Other cars/trucks I've driven are usually off by much more. Our Honda has never been closer than 3 MPG.
Ok, when your daily commute is 130 miles (without the honey do errands) then you have a tendency to review gallons, miles, mpg, costs, etc. I'm afraid if get a scan gauge it might push me to being obsessive about it, instead of just enjoying my truck. On the weekends I put my gauge on "compass" and drive it like I stole it, but on Sunday, fill it back up and back to the mpg meter, give me something to do while driving I guess. If these reading are within normal, then I'm good. Thanks
03-05-2020, 08:31 AM
Gallons used is that an average or total per trip?
