I was wondering what how accurate people find the NAV system average mileage display to be? I was trying to figure my mileage when I discovered that I did not have all the information I needed on my gas receipts, so I was thinking on taking the Ave MPG from the NAV system since I have not reset it since I got my FEH. Mine says I'm getting 27.4 MPG ave, but I'm not sure how accurate these things are.

 

I reset mine every tank, and at times have reset on specific trips to gauge my driving techniques. In the first few thousand miles my NAV showed about 10% higher than the gas-in. Lately, during the past several thousand miles the NAV has been about 10% lower than gas-in.

 

I can't comment on the Ford Escape Hybrid, but most Prius drivers find the display to be about 1MPG higher than "actual," calculated by the pump reading and distance.

 

You've also got to rember the FEH has two fuel economy displays. For us poor folk like me(no nav system), the message center on the dash provides average economy. Thus far, the message center avg fuel economy has been reading .5-1.0 mpg lower than my calculations using the pump and distance method

Which inspire me b/c the display says 28.5 mpg this tank...so maybe I'll get close to 30mpg for the first time. FEH is still breaking in with 1100 miles thus far.

Nate

 

It sounds as if the Dash mpg rating is closer than the NAV mpg rating. My FEH does not have a fuel economy display on the dash screen (I assume because I have the NAV unit). Does anyone know how to activate this option in the dash display?

 

It's one of the screens you cycle through with the "Info" button just above the climate controls.

 

You get one or the other. The computer "knows" you have the nav system and disables the duplicate screens. In theory it's based on the same data, but I suspect the module that snarfs the data from the CAN bus and sends it to the NAV Radio is a little slow and misses some bits from time to time. I've seen the instantaneous bar drop from MAX to zero then reappear a second later.

Also I don't know what happens calculation wise on the average if you leave the radio turned off.

 

Hmm. interesting.
I'll have to borrow my friends Neo VI box (a CAN bus reader tool) and see what I can find!