I disabled AFM as an experiment.

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by stchman, Aug 26, 2013.

  1. stchman

    stchman Active Member 2 Years 1000 Posts

    I used my Hypertech to disable AFM on my truck as an experiment. SO many folks are constantly talking about oil consumption, AFM makes for WORSE MPGs, etc., that I thought I would give it a try.

    With AFM I get between 17.8-18.3 MPG Monday through Friday back and forth to work.

    I disabled AFM last night and topped off the tank this morning for the drive.

    I got 20.1 MPG driving to work, which is surprisingly slightly better than what I get with AFM on. Now I know weather, fuel blends, etc., have an impact on fuel economy as well, my driving back and forth to work at least takes the terrain out of the equation.

    I will keep the forum posted.

    At the very least, I don't have to hear the AFM turn on and off and hear it on my exhaust.
  2. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    So were we right?
  3. stchman

    stchman Active Member 2 Years 1000 Posts

    I'm not going to declare anything after only 25 miles. So far it looks promising.
  4. Sierraowner5.3

    Sierraowner5.3 Epic Member 5+ Years 1000 Posts

    something to bear in mind is the fact that the ECM relearns things as you drive, so as you get more miles on it should only get better.

    at least for me, the sweet spot if running 60-65 with the cruise on. flat ground the truck returns 23 on the instant econ display, and lots of interstate driving seems to support that.

  5. stchman

    stchman Active Member 2 Years 1000 Posts

    The absolute best I ever got on my route to work for the week was 18.8MPG. Not bad for a heavy truck, but if it can do better with disabling AFM, then I'll do it.
  6. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    I cant wait to get my Diablo and see what kind of numbers my truck will get :glasses:
  7. ChevyFan

    ChevyFan The Sheriff Staff Member 5+ Years 1000 Posts

    You should chart it. Do a daily log and include the total miles, the MPG shown, weather conditions, etc.
  8. McClintoc

    McClintoc ɹoʇɐɹǝpoɯ Staff Member 3 Years 1000 Posts

    For the most accurate results, go through several whole tanks with AFM off and then get back to us. Good luck with the experiment!
  9. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Good thread topic...thanks for starting it!
  10. stchman

    stchman Active Member 2 Years 1000 Posts

    Update, day 2.

    I arrived at work with the DIC reporting AVG MPG of 19.1. I will report back tomorrow.

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