MPG Computer

[NNovak]

Any one know how to get this to more accurate????



I am compareing the display with manual calculation and it has been anywhere from 3-4 mpg off on the high side. Not fun... depressing to look at it and see 20. 2 ave and then calc out 16. 2... .



First I thought maybe it had to do with using ULSD but these last two tanks I used LSD and it was the same amount off. But my MPG were better with the LSD.

 

[DonMartin]

Any one know how to get this to more accurate????



I am compareing the display with manual calculation and it has been anywhere from 3-4 mpg off on the high side. Not fun... depressing to look at it and see 20. 2 ave and then calc out 16. 2... .



First I thought maybe it had to do with using ULSD but these last two tanks I used LSD and it was the same amount off. But my MPG were better with the LSD.

most people have the same issues and i dont know of any fix other than mabybe talk to dealer and see if they have a updated flash that might help



just get used to it and always base your mpg off hand calc but try to have a idea of what it is really getting when it says 20 on the overhead

 

[JMoberly]

The good thing I have found in my experience is that it is off by the same amount all the time. So I use it as a rough estimate to remind me to stay off the skinny pedal. I also keep an eye on it for a sudden drop which could indicate a problem.

 

[BigPapa]

I would say the inaccuracy comes from an inaccurate fuel level sending unit. The computer has to be calculating how much fuel you've used by how much is left in the tank. If the sending unit is not accurate this would throw off the calculation.



Scott

 

[betterthanstock]

I think the accuracy improves if you don't top it off when filling up, and drive it until the low fuel light comes on. After a few tanks it will be a lot closer.

 

[Vaughn MacKenzie]

Ever since the 24v came out Cummins has had the software in the ECM that can be interfaced to provide accurate MPG numbers, but Dodge is too cheap to utilize it. It's based off of fuel flow not TPS position, all you need is fuel flow rate and vehicle speed to calculate MPG.



Vaughn

 

[roperteacher]

I don't know why they even bother having one????? Didn't dodge come out with a flash a few years ago that actually made the readout wrong on purpose becasue people were complaining about Fuel economy???

 

[DHuffman]

Leave it on compass / temp and quit worrying about it. It is useless...

 

[Dieselnerd]

Interesting replies, mine is very close to actual. I do reset it every time I fill up. If you don't reset it the error probably grows with each tank.