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Active Fuel Management

Discussion in 'Performance & Fuel' started by chemcounter, Feb 19, 2010.

  1. chemcounter

    chemcounter New Member

    I am looking to buy a used silverado with 5.3L with active fuel management but have found many dealers don't advertise whether the vehicles have it or not. My father recently purchased a new 2009 silverado thinking just because it had the 5.3 it would have AFM but was disappointed when it was delivered and didn't. It is a real pain to call many of the dealers with used vehicles ask them and most of the time they have no clue or would just lie to get me to come in.

    Short of opening the hood, is there something in the VIN or somewhere else on a truck that would indicate it has AFM? Is there somewhere under the hood that states it has AFM if I am able to?
  2. lalo56

    lalo56 New Member

    They have an emblem on the rear that says Flex Fuel.
  3. 06MonteSS

    06MonteSS New Member

    FlexFuel just means it can run E85 gas in it... doesn't mean it's got DOD/AFM...

    usually, on the black plastic engine cover, it'll say right on it Active Fuel Management or Displacement on Demand
    Last edited: Feb 19, 2010
  4. donl

    donl New Member

    I have an 2009 with the AFM and I think it's a joke. If it was so great why doesn't it go into the 4 cylinder mode when it's just idling. Don't get me wrong...I like the pickup but that's just my 2 cents.
  5. JennaBear

    JennaBear New Member

    Majority of our customers ask for the AFM to be turned off.
  6. vncj96

    vncj96 New Member 1000 Posts

    the dealers know, they are just being lazy. the AFM engine and the flex fuel engine are two completely different engines

    i dont remember which is which but one is an iron block and the other is an aluminum block
    Last edited: Feb 20, 2010
  7. 06MonteSS

    06MonteSS New Member

    yep... I always disable it in my tunes for people as well...

    I've actually gotten BETTER mileage with it disabled... heh..
  8. 06MonteSS

    06MonteSS New Member

    because there are certain criteria that must be met before the DOD/AFM is allowed to kick in by the ECM... have to be at least over 20-30 mph, but under 80mph... has to be less than a certain amount of engine load... less than a certain amount of % throttle position... has be between a certain rpm range... has to be within certain amount of vacuum pressure... etc etc etc...

    all of which can be tweaked in a custom tune to change the behavior of it... like making it go into DOD/AFM sooner, stay in 4 cyl mode longer, etc etc..
  9. bigdaddy77084

    bigdaddy77084 New Member

    Sounds like more things to go wrong..
  10. donl

    donl New Member

    My 09 has AFM and is a Flex Fuel engine to burn the 85% ethanol crap that I'll never use.

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