Does anyone know how much fuel is left in the average tank when the fule light comes on?

Yesterday my came on and I went to feel up but only go tto put 27.7 gallons in. Im pretty sure i have a 35 gallon tank. Thats almost 8 gallons left in the tank when the light comes on. Does that sound right? I never depend on the gauge as it is intemittent.

 

7-10 gallons left in the tank is about average. Probably good because with the long tank and an uphill the fuel could end up opposite the suction line and you would run out with fuel in the tank.
Also fuel is used to cool the injection pump even on 12 valves. Having a larger amount of fuel in the tank provides more cooling due to more of a heat sink for return fuel.

 

That's about right. Mine was about the same befor my sending unit went south in Wyoming last summer with my 5th wheel. I thought my mileage was getting better until I filled up with about a gallon left.