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  1. #1

    Question Active Fuel Management

    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. #2

    Default

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

  3. #3

    Default

    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 by 06MonteSS; 02-19-2010 at 12:57 PM.
    06MonteSS


    2014 Camaro SS - 2SS, RS pkg., short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake

  4. #4
    Jr. Mechanic
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    Default

    Quote Originally Posted by chemcounter View Post
    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?
    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. #5
    Sr. Engineer
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    Default

    Majority of our customers ask for the AFM to be turned off.
    Black Bear Performance- Custom Tuning Solutions

    Authorized EFILive and MAGNACHARGER seller

  6. #6
    Legend

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    Red Wing, Minnesota, United States
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    Default

    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 by vncj96; 02-20-2010 at 05:36 AM.
    99 K1500 Suburban LT "THE BEAST"
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  7. #7

    Default

    Quote Originally Posted by JennaBear View Post
    Majority of our customers ask for the AFM to be turned off.
    yep... I always disable it in my tunes for people as well...

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

  8. #8

    Default

    Quote Originally Posted by donl View Post
    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.
    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. #9
    Master Mechanic bigdaddy77084's Avatar
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    Default

    Sounds like more things to go wrong..

  10. #10
    Jr. Mechanic
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    Quote Originally Posted by vncj96 View Post
    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
    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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