Today I ran my truck until the fuel warning light came on. This is this first time I did this. I wanted to see how accurate the overhead computer was in relation to DTE (distance till empty) and the actual fuel left in the tank.<br>Here's the results: When my low-fuel warning light came on I drove about 5 miles to the Flying J for fuel. The overhead computer indicated 88 DTE. I took on 25 gallons and had 491 miles on the trip meter. I have 34 gallon tank, which left me with 9 gallons when the warning light came on. I got 19.64 mpg. At that rate, I could have gone 176.76 more miles until I ran out...double what the DTE had indicated!<br><br>I guess the bottom line is; the overhead computer is not that accurate after all. I'm very happy with the mpg though. At least now I know I really don't have to sweat it when the low-fuel warning light comes on. ..I'll have plenty of time to find fuel. But I'm the kind of person who likes to refuel when I get down to between 1/4 and 1/2 a tank though. Now all I have to do is convince the CFO that I need a combination aux. fuel tank/ tool box!

 

The overhead mileage is based on the average of the last 30 gallons. If you want to do it again, reset the computer to 0 mpg in the ECO mode. After doing that a couple of times mine got to within about .5 mpg accuracy.<br><br>The fuel light will come on with approx 9 gal left. Supposedly that's so you don't run out and starve the pump.

 

Thanks for the tip....I'll give it a try.

 

Something else to consider, The Injection pump is cooled by the diesel fuel running through it.<br>As the fuel level in the tank drops, then temp of the remaining fuel in the tank increases, due to less mass to absorb the excess heat. <br>Each time the fuel is cycled the fuel temp will rise. <br>Instead of the tank cooling the returned fuel, the returned fuel will heat up the tank.<br>This could be another reason why we get the low fuel light with 9 or 10 gallons still in the tank.

 

Shovelhead makes an important point!<br><br>Also, it would be interesting to have some data on how many run their fuel below the &quot;low fuel light&quot; level and have had trouble with their lift pumps/injection pumps.<br><br>Is there some relationship? I don't know, but its always been a thought of mine...and I have never seen any data on it.

 

My overhead computer only tells me the outside temp and the direction that I am traveling in. I know in are old Caravan we had the same type of computer but when you hit the button it cycled functions. My truck just turns off the screen when I hit that button. Is this specific to a 96?<br>

 

they updated the computer to read more functions in 99<br><br>DRecu!

 

Oh, no wonder my comp does nothing but one function. Thanks, Jeff<br>

 

i run mine often to below when that light comes on, had a bad lift pump at 16,000 on 2002