I Have A 95 Dodge 2500 That Loves Fuel!
After New Tranny, New Motor, 215 HP Fuel Plate, New Air 2 Air Cooler, New Turbo, New Everything! Still Pulling 8 Mpg Empty! I Have A 97 Dodge 5 Speed Flatbed Pulling 23 Empty. What The Hell? Any Advice On How I Can Improve Or May Have Missed?????

 

stock tires ? trans gear could be wrong and I'm sure your getting at least 15-17 ... i have a 215 engine w 887 pump ... get minimum 16 cold when i have to let er idle ... and i drive with the lead in da foot ...

 

That is certainly odd. Before my truck started acting funny (see "HELP Fueling Issue" thread) it would always return at least 18 mpg empty.

I would try two things to make sure the calculated mileage is correct.

1. Top off the tank, stopping when the nozzle kicks off the first time. Then drive a known distance to another filling station and top the tank back off using the same "click off" procedure as above. Calculate mileage. You should be able to get an exact mileage from point A to B on Google maps. For that matter you might compare the mileage to your odometer reading to see if it is counting correctly. (This won't be perfect by engineering standards since one pump might kick off a little sooner or later than another, but it will be close enough to prove whether the 8 mpgs is correct or not)

2. To echo 4x4manonbroke tire size can have a big impact on both efficiency and the odometer reading. To calculate a correction factor for the odometer you just need to know the percentage difference in the circumference of original equipment tires and what you are running (I have to do this). You can then just multiply your indicated odometer reading by 1.whatever that percentage is and calculate your mileage.

I imagine it would take some awfully big tires to reduce the actual mileage from around 18 to 8, but between the added weight, rolling resistance, and odometer error calculated mileage could be off that much.

 

I have to add 1 mile every 10 on my ford and i went from 33 to 35 tires .... i dont see how its even possible to be off that far unless you have the wrong speedo gear in trans and its throwing the milage WAY OFF !!!!

if you go down the highway ... there are mile markers ..... each one is exactly 1 mile apart ... go 10 miles and see what your odometer reads ... ( Reset your trip meter ) and go by that ... i'm guessing its not calculating milage correct at all ... is yours a 47 RH or RE ?