I have seen a number of threads here about the digital display or "lie o meter" as some refer to it in regards to MPG etc... that it displays.

Well today I ALMOST found out the hard way that when it displays "0 miles to E" it is pretty dead on accurate. I saw it counting down miles as I was driving and assumed that there was a reserve even after it said 0 miles. I was getting off the freeway when it stuttered once...and then twice and then a third time. Luckily I crested the top of the off ramp, rolled a right on a green and then into the local gas station.

I don't know exactly how the computer figures out all that stuff but I am now a FIRM believer in that little digital display and all it's information.

 

Well Dude, you're probably one of the few believers in that thing. I would love to be able to trust it, but when mine says I have 640 miles to empty, when I know at best I can get 530 miles to a tank, I don't trust it on bit. Just my $.02

 

I've always read that the Miles To Empty is pretty darn accurate. It's the Avg. MPG that tends to not be spot on, especially if you have a tuner of any sort. For example, DP-Tuner on the 7.3L tends to make the overhead display just about 3mpg over what you'll find when you hand calculate.

I trust the Miles to Empty pretty firmly, though.

 

Mine has been right a couple of times after highway driving , however it normally takes 25 of the 29 gallons that the tank holds when reading "0", meaning that theres still 4 gallons left in the tank .

 

I have rolled an additional 7 to 10 miles after it has read empty. Thankfully on a level surface vs. up & down. That way it can suck up the last of it from the bottom of the middle of the tank where the low spot & pick up are.

Yeah, miles to empty is prety acurate, Now that I Harpooned we'll see if it learns the new capacity.

 

I would agree that on a full tank it's questionable, but the last 25 miles are darn close. I personally ran out around 4 miles after it went to 0 miles left.

 

I bolded why you can't trust yours. The mileage calculation was done with a stock truck. If you add a tuner that calibration is no good and you will get funny results.

 

I recently ran out of gas because I believed the miles to MT. Just before the truck died it flashed 10 miles to E, then counted down to 2 in seconds. Leaving me high and dry on the Interstate.
F150 stock Lariat, 2009, 5.4, pulling a travel tailer. Is there some way to reset and or calibrate this thing? If not, how about just turning it off?

 

if your running a diesel and let it run out your taking a chance on wiping out your injector o rings. dont let em run low guys.

 

I've spent a lot of time playing with this thing and trying to figure out how exactly it works... mine gives bogus numbers as well.

After much observation I have determined its a function of your avg. economy and your current fuel consumption rate. My low fuel light comes on when I have a range of 50 miles according to lie-o-meter, however depending on my driving style determines how long it takes.

It does not subtract mile-for-mile but seems to say 'okay you should have 50 miles left' but then it adjusts itself to accordingly to give a reading all the way to empty.

I had it down to 7 once and drove another mile to the gas station and put in 35 gallons. Depending on what I read I have somewhere between a 38-43 gallon tank.

Moral of the story, that little lie-o-meter is as accurate as a MI weatherman. The only time it is accurate is at the last minute or after the fact. Thus treat it as if it was a MI weatherman... if it says once thing, just use it as a guestimate... from experience, when it says 30 miles left thats ur cue to get gas.

 

Well, like so many other things, you're mileage may vary! I kinda got stuck once and got mine down to 9 miles to empty. I pulled into the station, and I was able to put 39 gallons in my 38 gallon tank. I don't intend to ever let it get that low again. But, there's my story.

 

I have a rhetorical question: Why are you running it that low?

Personally, I run mine until the low-fuel light is on, and sometimes even a bit after. I don't have the lie-o-meter to rely on to tell me to get gas

I can understand being in a sticky situation where there's no gas station around, or diesel for that matter, but...

 

Well, for me, like I said, I had a brain fart and kinda let my mind wander. I normally only let it get to a quarter of a tank, if that. For one thing, too many of the stations around here still have that stupid $75.00 limit on my card. But otherwise, I just don't like letting it get too low. I learned my lesson...won't do it again.

 

Mine has been pretty accurate, within 1/10MPG when calculated. BTW, it is not a good idea to run the truck below 1/4 tank... gas or diesel, but especially diesels. It is so hard on the fuel system, I don't really understand why people run these trucks down to next to nothing. End of lecture.

 

I am with you on this one.When the light comes on I plan a fuel stop.