Then why would the Owners Manual say what I just quoted. Also when I had my 60 gal Transfer Flow tank added, when they restarted after removing the tank and gage with fuel pickup, unsealed, then hooked it back up to the new tank and it took about 10 to 15 seconds to restart. BUT advice taken, I will approach full empty carefully over time. I am convinced that I can get the process down to 4 or 5 gal reserve before fill up, which should take 55 or 56 gal to fill the 60 gal tank. There just has to be some extra miles from zero miles on the tank at DTE or MTE reading by my calculations, at gage empty I should still have about 9 to 10 in the tank. Time and Testing will tell.

 

The display is more accurate than doing the math. If you have not noticed your miles to empty does not always DECREASE, in fact it will often INCREASE. WHY? Because it constantly is computing mpg based upon the Trip screen you are on. SO I rolled in the other day and knocking out 993 miles last week here in Texas on a business trip. Pulling heavy the whole time. I drop my load, hit the pumps and my mpg was at 10.6. I fill tank with 43 gals and made a trip into town and my mpg went up to 16.6 and finally dropping down to 16.2 when I got home.

The display showed I had only driven about 12 miles on a near 50 mi rd trip...note the display only shows how miles you have left on that tank, NOT how many miles you have gone!

The result is a floating and constant computing of MPG and miles left on tank.

That data is not captured when you do the hand math.

Now some will say well its not accurate, it is accurate and even if its off its consistently off which makes it work. Hand math works best over the long haul IF you keep a log book like a Fighter Pilot does. You input the exact mileage to the tenth and the exact fuel at each fill to the tenth. DO that for a couple of thousand miles and run the numbers and I will bet when you compare its will be +/- .1

I have compared mine and over the long road they are almost dead on when you compare to lifetime numbers, if you are within .5 you are inside the margin of error envelope.

 

It's not in the owners manual because you SHOULD do it. It's in there in the event that you DO do it.

All I'm saying is that it is best to avoid doing it, ESPECIALLY in an EFI vehicle. The non-EFI vehicles are more forgiving of it for a variety of reasons. In the end, it's your truck and your money. Do as you please.

 

Yes. I am talking about each trip, not real time mpg. I reset the trip at each fill up and the computer is always over stating the mpg.

 

Resetting the trip DOES NOT reset the fuel economy calculation. You have to reset it separately.

 

It is my understanding that running a diesel out of fuel is risking damaging the fuel pump and injectors, as they are fuel lubricated.

 

Im not arguing Mark I think some of us just may not be getting what you are saying. When I want to check the fuel economy of a specific tank full of fuel I reset the trip when I get in the truck after filling up. The trip fuel economy does reset. I agree it does not reset the overall truck fuel economy. I am certainly not getting the same fuel economy reading on that tank that is showing for the overall economy. At the next fillup I rinse and repeat. I might be total missing what you are meaning however. Now is the trip fuel economy as accurate as the overall fuel economy? Probably not. Having said all this however, I am now past the break-in period so it might be a good time to reset the over all fuel economy.