i was just wondering what everyone's stupid overhead mpg reading is? I know its never right. Mine barely moves from 20 mpg. I can make it around 500 miles each tank. Mostly city driving. 500 miles with 34 gal talk is about 14-15mpg right? Why does dodge make so many stupid things that don't work properly? Does your mpg number pretty much move quickly with your driving, or not move like mine?

 

In my 06 95% of the time the overhead reports lower mileage by 1 to 2 MPG then what I get when I calculate it by hand. My overhead will move very fast if I put my foot in to the injectors. Being you have a BDTD hooked up your overhead will be off even more as it lies to the computer.

 

you got to remember, that reading is from every single time that truck is running since the last reset if its even been reset......so that includes idle time, flogging it, in town driving and freeway cruising......

 

I reset it a lot. Pretty much everytime I drive it. Usually it only moves when I push the reset button.

 

I reset the overhead on my 05 everytime I fuel.
There has been a three mile difference between what it shows and hand calc.
So When I look at the display, I just deduct 3 off it.

 

That thing (at least on the 2nd gen's) takes an average of the LAST 20km and it also depends on how hard the go pedal is pressed. For mine, generally on the hi-way it is pretty good. trips in town and short stop and go it is all over the map and it can not be trusted.

 

Mine has stayed around 15 mpg since I have had the truck. I bought my rig with a lift and running 37's so I can't really tell what I am getting. For some reason I cannot get my triple dog to recalibrate my speedo. My gps tells me I am about 8mph off. So I just try to be careful in town.

 

The triple dog only recalibrates a chev I think. When I sold my TD to a guy with a chev, the option came up for his truck, but never came up for mine.

I get about 18mpg with my truck stock.

 

I had an '03 gasser Dodge and went to an '06 Cummins. The two computers work completely differently. Our '03 mpg would change very quickly up or down after it was reset. Our '06 makes very slow changes after it was reset. I just had it in on some warrantee work and they said that is normal on the newer computers.

 

I think it was due to people complaining that the new motors had such poor economy compared to the overhead's in Ford and Chevy trucks, so to improve the economy, they reprogrammed the overhead in Dodge to be as optimistic as those in Ford and GM trucks. FWIW I track every mile and gallon of fuel and the overhead (even stock) was always 2.5 to 4 MPG off. With the Smarty on anything other than setting "1" it got more optimistic, where I'd see mileage of 24 - 26 MPG. Reality is 17-19MPG depending upon load, weather, driving style...