GEN 2 Miles to empty: how does it work?

[NHnewbie]

2018 SCrew owner here. Almost 7000 miles on the truck so far and no problems of any kind. Still learning some of the finer points and now wondering about the "Mi to Empty" display. Specifically, how is this reading determined? I have searched the forum re this topic but have found no definitive answer. Some data:
> trip computer gives mileage as 18.9 MPG since delivery.
> miles to empty reading varies from about 630 mi to 700 mi at fill up.
> running 93 octane, 40 psi tire pressure on OEM tires and OEM beadlocks.
> suburban and highway miles only, no city; rarely get on it.
> AS/S disabled.

Some questions:

> what is the algorithm for determining MtE?
> how is fuel level in tank determined? Conventional float type sensor or something more accurate?
> does ambient temp affect MtE calculation?

Thanks for any insights.

 

[Derail]

Not sure but, you might try searching for DTE (Distance to Empty)

 

[goblues38]

the last 5 fords I have owned (13 - SHO, 15 - Mustang GT, 14 ExSport, 18- ExSport, 18-Raptor)

Ford Pulls MPG from previous 100 miles to gain your average. Then multiplies that average x how many gallons the computer thinks you have in the tank.

So. If you pull off the highway after doing several hundred miles @ 18 mpg.....you will see a range of 648 on a full 36 gallon tank.

Now lets say you spent the day off road, getting 10 mpg. reset your fuel economy and did 20 miles on the highway at 18 mpg. When you fill up this time, the range will only be 500 on a 36 gallon tank. regardless of what you past MPG says.

The computer always uses the last 100 (do not know exact number) miles as history to estimate range....independent of the average MPG in the trip computer.

 

[NHnewbie]

The computer always uses the last 100 (do not know exact number) miles as history to estimate range....independent of the average MPG in the trip computer.

Thanks!

 

[jaz13]

I don't have any inside information, but it is based on a rolling mileage calculation. No idea if it is last 60 minutes or what, but it is not tied to trip computer 1 or 2.

I have no doubt the tank measures volume, so that means it is modestly affected by temperature fluctuations of the fuel in the tank. But the density of fuel changes so little that other errors will have a far larger impact on the reported mileage.

Without a doubt, the biggest contributor to the fluctuations you see is the type of driving you did over the last hour or so.

 

[Seven]

Once you calculate your MPG via the self calculation method by dividing miles driven by gallons of gas, go update your raptor so it calculates accurately. Follow the video and instructions here.

https://www.fordraptorforum.com/threads/forscan-changes-tweak-your-truck.52149/page-119#post-1288182

 

[OriginalToken]

Yeah, prior to the ETM adjustment my indicated MPG, and so the miles to empty indication, always read high. My indicated MPG was commonly between 1 and 2 MPG too high, for example with 15 MPG real mileage (my calculations based on fuel input vs miles traveled) I might have indicated as much as 17. So yeah, when I had 21.5 indicated it was not really 21.5 MPG

I did the ETM adjustment, and now my indicated comes out within a tenth or two of the real mileage.

T!

 

[Quaesta]

I wish I could make mine lie to me and tell me better than I am getting...

 

[NHbeast]

Two recent experiences with the 50 MTE warning.

1. Had been off roading getting about 14 mpg? (unknown really)
Got on paved roads and drove about 30 miles when the warning came on.
Filled up about 5 miles later with 20.3 gallons. (SCAB 26 gallon tank)
Also inflated the tires to 42 from 25.
So, there were 5.5 gallons in my tank just after the warning lit.
The MTE calculator figured I was getting 10 mpg? Or worse.

2. 50 MTE light came on after 294 miles of 70 plus cruising.
Add 35 miles to the next fill up of 23.73 gallons with 12 MTE indicated.
So, there were 2.25 gallons in the tank with 12 MTE indicated.

Ergo, if I get to 0 MTE there might be a bit more than a gallon in the tank.
Not planing on testing the theory.