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Silverado MPG Computer in Truck

Discussion in 'Performance & Fuel' started by Kolaz, Nov 25, 2009.

  1. Kolaz

    Kolaz New Member

    Hey guys, I recently got in an argument with someone about this. I understand the math related to how the fuel economy is calculated, using MAF and fuel-flow and such, but what I want to know is, how is it calculated overall? In my 2008 Silverado 2500HD with the 6.0 Vortec, when I reset the Average Economy, Trip, Miles used, etc. I find that my average economy jumps up and down, from 22.0 MPG to 7.3 MPG. My friend tells me I'm wrong. He says the fuel economy is calculated independently each mile, regardless of what the previous mileage is. However, I think that it averages all the mileage overall, unless it is reset. This might not be very clear, but I hope this helps with an answer.
  2. TRPLXL2

    TRPLXL2 Epic Member 5+ Years 1000 Posts Platinum Contributor

    There is no way in hell it would read 22mpg with the 6.0 motor, not even at idle would you get that kind of gas mileage on that truck. I think you have an electrical problem if it is bouncing around like that, mine would change but not that radical. It would go from 14.0 to 14.3 and back down, and that would be over a 100 mile trip. I have also gotten into arguments over this same issue with guys at work, I really don't think the DIC is accurate.
  3. mountaindan

    mountaindan New Member

    I don't have a computer in my truck, but based on the computer in my wife's Toyota, you would definitely see a lot of variance when you first reset your computer. The more miles you drive the less variation you'll see. It would not surprise me at all to see 20+ when you first reset it. If you have an instantaneous MPG function you will see it all over the place, I've seen 30 or 40 mpg down to 2 or 3 at any given time. The overall average is based on the miles driven and the number of mpg calculations it takes during those miles.

    That's my 2 cents, for what it's worth!
  4. XS ive

    XS ive Rockstar 100 Posts

    If the truck is idling, the MPG would be 0, you are using fuel and going nowhere.
    According to manual, the average is calculated from last time of reset.
  5. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    My 1995 GTP had a setup just like that and I could use it for instant economy or life of the car, and you could reset the life mpg and then it just starts over from the moment of reset. When using my instant eceonmy I could get readings anywhere form 38 to 7mpg. And yes that it is possible to pull 22 mpg on a 6.0. IMO those are actually pretty accurate little computers, the one in my GTP was always nuts on when I would do the math myself.

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