So I got back from a trip to Lethbridge today, and figured I'd check the fuel economy calculation from the DIC to what the trip odometer and fuel pump said.

For this trip, I just set the cruise control at the speed limit (mostly 110 km/h) and let pretty much everyone else on the highway pass me (four lane divided highway all the way). Damn, that was hard to do

Anyway, the DIC said fuel economy was: 8.3 liters/100km, or 28.3 MPG (US gallons). I thought that was pretty good.

Fuel Pump/Odometer calculation: 42.5 liters and 529 km (~11.25 US gallons and ~329 miles) for 8.04 liters/100 km or 29.25 MPG (US gallons) or 35 MPG (imperial gallons). Have to admit to being surprised at the result, never figured the GXP would get that kind of mileage.

So the DIC was within about 2.5% on the mileage calculation, not too bad, I think. Anyone else bother to check out the accuracy of theirs?

 

ya my DIC is pretty accurate sometimes it misfires

 

mine reads a consistant 1.3 MPG low. City, highway, mixed, don't matter, almost always 1.3 low. That would be 5.6% low on the mixed numbers I actually get. BTW, now that the little V8 has started to loosen up (43K miles), the mileage keeps getting better every day! DIC will show 22 MPG with the cruise set at 83 MPH and hovers around 27 at 75 MPH.

 

If I run the stock tune or don’t adjust the fuel trims with the DS tune, my Imp DIC also reads about 2.5% under actual. I have not gotten quite your mileage but only have < 20K and have gotten just over 28 real MPG. My DIC seems to be really close when I adjust the trims +3. I used to drive the truck all the time, but with the cost of gas I drive the Imp more often. I hope my MPG goes up like the rest of you with more mileage, then again I guess I could keep it below 70.

 

Mine is usually pretty much dead on...but these days, with all things considered, I just reset the trip meter and pray that I get a few more miles next tank.

 

I've actually done the math myself on the last 3 fill-ups and found the DIC consistently showed 1 to 2 mpg better than actual.

 

my DIC curves to the left..