I have allways had a overhead that was off by a few gallons from tank to tank since adding my power boxes. Usually in the 2-3.5 gal range. Don't even watch it any more but just reset every time to see how off it is. This last 2 tank fulls though have seen a difference of 12mpg!!!

Oh how I wished it was even remotely close to the displayed 34.5mpg!!!!! Was more like 21.9mpg. How in the world can it be off by this much? Is there any reflash the dealer can do to recalibrate it?

 

mine works fine, always within .5 gal. I heard of re-flash effecting the accuracy

 

Well, I can garantee the reading in my 02 of 25 mpg after my recent mods is bogus! I'd also like to know if we can change these in any way.

 

take off your fueling boxs and if you have injectors, put the stock ones back in. keep your fueling box off, drive 65, without changing anything, turn the box back on. Watch how your truck will take off.

 

I'm at a lose as to what this has to do with the overhead readout Sorry if I'm dumb, I just don't get it.

 

Because when you have a box or injectors, the throttle pedal is not pushed in as far which in turn gives you better readings. If you are going 65 with no box and then turn the box on without changing your pedal position, it will start to accelerate. So what do you do, you let off until you reach 65. Now your overhead computer reads 10 mpg more. Hold the 65 with the box on and without moving the throttle turn the box off. The truck will slow down so in turn you have to give it more fuel. All the computer reads is how much you have the throttle pushed in.

 

O. I see. Ya. I just wish we could correct it. O well, pay to play!!!

 

I don't think so!.....so if I idle around in Drive I should have to drain fuel....works off of fuel consumption not throttle position....Your boxes are messing with it's "P" brain!

 

xyzer, it works off how much throttle you are giving it for a certain speed. If I idle in 1st gear it says I get 9 mpg. If I idle in second it might say 11mpg. You are giving it no more fuel, just more speed. How does that work? Well the computer senses if the throttle pedal is being pushed and what the speed is. The computer knows no difference in how much fuel is going through the lines. If so, it would tell you how many gallons of fuel per hour you are burning.

 

Yep, with the box and injectors I was showing 26.5 MPG pulling our 5th wheel (see signature) on a flat and level section of I-40 coming back from Tennessee. I could only wish!!!

Rusty

 

Yep-the basic gist of this is that your fueling boxes and injectors cause extra fuel to be injected that the computer does not know about. Regardless of how the computer actually does the calculation, this is what throws the numbers off.

 

So, is there any way to get it recalibrated or not????? Thats what I'm wondering here.

 

Not that I'm aware of.

 

I'm not sure why your trucks are diff. than mine I run a juice and it's pretty much the same w/or wo I don't get the outrageous #s like 26mpg I get 19-22 not towing and 14.5- 16 when towing, depending on how I drive. It's always within .5 gal.

 

My overhead has displayed 12.5mpg consistently since I installed it back in January, but yet I calculate out to 17 to 20 mpg depending on driving conditions. It doesn't seem to matter how I drive, it always end up at 12.5mpg. If I reset it on the fly it will show an instantaneous of 18-24mpg but by the time i get to the bottom of a tank it's back to 12.5.