Maybe thats the difference. I tried towing DTE setting once, didnt notice any difference, so I went back to normal. Normally takes about 2 tank fulls of fuel to get DTE back into the 400's after a long tow. Someone here said that there is in internal 500mile "average MPG" that is used to calculate DTE. Maybe the towing DTE setting is a shorter "average" thereby getting the DTE more accurate quicker.

I will try that after a long tow. which will be some number of months, now that we are in the winter season up here.

 

Ok, that's all I can think of too. The towing mode should be using a shorter length of time to take snapshots of fuel usage in order to build the calculation for fuel remaining in the tank. So then maybe the normal mode uses a greater time span with the hope of building a more accurate estimation?

Seems kind of useless to me, why the two different options? Just one would be fine since we all have found that the system is very accurate regardless of which option we choose.

 

I think I might just stay in normal mode regardless. It provided what I thought was accurate DTE calculations and I was happy. KISS.

 

I have found that mine will recalculate after a few miles. If I have been towing I will have about 400 miles to empty with a full tank. If I unhook from the trailer and drive for perhaps 30 miles I will find the DTE will have recalculated and show more miles to empty. The reverse is true if I have been running empty the hook up to the trailer. After about 30 miles my DTE will have adjusted to fewer miles. My old truck, 99 F250, required about two tanks of fuel to adjust.

 

I I realized that this is a very old thread I just couldn't believe what I was reading. ANY vehicle that calculates distance to empty uses your average miles per gallon to do it. If you reset your average and drive the required distance usually around 50 miles it will recalculate based on your new average. the thing that bothers me is distance to empty is a simple math problem gallons x average MPGs equals distance to empty. And I can't believe that so many people are having an issue with it. Distance to empty is the number based on an estimate of the gallons remaining which makes it not exactly accurate, also averaged MPGs is a fluctuating number which also makes it slightly inaccurate. When you choose towing for your distance to empty calculation the computer knows to err on the low side not the high side that's all.

 

I believe the frustrating thing is it takes forever or never to actually update. For example, fill up and DTE based on 16mpg it will show 560+

Ok, now tow maybe 100 miles at 12mpg and the DTE will fluctuate and show a reasonable amount of miles remaining.

Unhitch and again driving 16+mpg, heck even 20mpg highway and the DTE doesn't reflect that... hit 1/2 tank and says 175 DTE... umm no it's more like 325 DTE

But whatever...

 

The the DTE is based on your rolling average MPGs unless you reset it yourself. So if you fill up your truck and drive a hundred miles towing getting 12 miles per gallon (you must tow something kind of small mine gets around 8.5) and then 40 miles at 20 MPGs then your DTE is based off of an average of 14.28. that's why they give you a button to reset the average with. All it does is do the math for you, it's never wrong. If you want the new DTE you have to reset the average when you're done towing. Otherwise like in the numbers I use above the computer is calculating that you're going to continue doing the same thing a hundred miles at 12 miles per gallon and then 40 miles at 20 miles per gallon for the rest of the tank.

 

There is a reserve of several gallons after the system shows "empty". The number is dependent on the size tank, but all have a reserve of 4 or more gallons just so you don't run out. The DTE uses the average over the course of the trip so if you are driving W/O towing for part of it and while towing for part, or if part is stop and go vs hwy driving, it will change the calculation as you drive. By not including the reserve fuel in the DTE calculation it helps prevent people from running out due to the inaccuracy of the calculation.

 

I call BS on that statement and challenge you to prove it.


If the Fuel Level Low light comes on I have 37 miles to empty on my 2016 and it is very accurate by doing the math.


Proof of the Fuel Level Low Light Is active @ 2866.4 miles


This image is showing 15 miles to empty and the odometer is reading 2867.0 miles.
If you look at the file name of these images you will see they were taken on April 1, 2017


This image shows Trip A at the time of refuelling, which is reset at every fuel up. I have the short bed with a 26 gallon tank.
You can see the computer has recorded I have used 23.9 gallons of fuel, traveled 246 miles since the last fill up and has an average of 10.3mpg on this tank. This contradicts the previous image that displays 11.7mpg.


This is an image of my log book from April 1, 2017

I recorded the mileage at 2867.0 traveled 246.0 miles since the last fill up and pumped 23.5 gallons into the tank. Doing the math that equated to 10.4mpg. 26gal - 23.5gal = 2.5 gallons remaining in the tank. 10.4 x 2.5 gallons = 26 miles till my fuel tank is empty. The computer was showing 15 miles to empty. At 0 miles to empty the computer would have said I would be out of fuel, when in reality I still had one gallon or so in reserve, which is pretty damn low considering that 1 gallon has to cover the entire bottom of the fuel tank.

Where is that 4 gallons of reserve you are talking about?

 

Damn dirt. You're dead nuts on this stuff. My DTE is all jacked up and I'm not really **** enough to do something about it. I take notes too...

But yea kid, dirt is really on top of this stuff. He just knows because of how he figures everything out like that.

 

first tank in my used 2011 CCSB, DTE was 3mi, MPG was 16.7 and total fill was 22gal. That leaves 6gal in the hole

I was wondering if the difference between reg & tow DTE settings are due to the estimated angle of fuel tank when the rear is loaded vs unloaded.....

 

Let me rephrase...once the fuel guage is on empty there is usually still about 4 gallons in the tank. I was not referencing the low fuel light at all, but the DTE calculation. But your vehicle will not be "out of fuel" when the DTE reads zero, or at least it wasn't on any of the 4 trucks I've owned with this feature. Ford has always held fuel in reserve in an effort to prevent people from running out, though it still doesn't work. How much fuel varies from vehicle to vehicle, and from 1 tank size to another. I don't recommend driving until the display shows zero, nor do I recommend using the DTE or AVG MPG as spot on accurate, because they aren't. I recommend filling up once you get below 1/4 tank when possible regardless of the DTE. But, if you simply cannot, you'll probably still be able to drive 10-20 miles before your engine dies.

 

Okay I'll let ya slide by on that.

I don't pay much attention to the fuel gauge but I think it reads empty at the time the fuel light illuminates which is at 37 miles to empty and for me that's about 4 gallons left. I would agree, the larger the tank the more fuel that's left in the tank at empty.