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  1. #11

    Default

    I'm old and the increasing complexity of these vehicles make me nervous. What happens in 10 years, is this system still going to function or cost a lot of money to replace. If it can be turned off then you can just ignore it. I keep my vehicle for a long time and expect this will be my last so I am agonizing over what I should buy.
    I sound like my father but I really long for the simplicity and reliability of cars and trucks from my youth.

  2. #12

    Default

    Quote Originally Posted by Restlessone View Post
    I'm old and the increasing complexity of these vehicles make me nervous. What happens in 10 years, is this system still going to function or cost a lot of money to replace. If it can be turned off then you can just ignore it. I keep my vehicle for a long time and expect this will be my last so I am agonizing over what I should buy.
    I sound like my father but I really long for the simplicity and reliability of cars and trucks from my youth.
    Vehicles built today are much better then there were even 5 years ago. I think that's one of the problems of the auto makers, they're building cars and trucks that you don't have to turn in at the end of 4 years .... in the 50's that's the life of a vehicle, today that's just getting broken in. The fuel savings has been estimated to be as high as 10% in some estimates. That's portentially going to save you maybe 500 gallons of fuel over 100,000 miles at $2.00 per gallon you'll save $1,000 over what you would have spent. If you had that technology during the $4.00+ gas peak you could double that figure in savings costs.

    This stuff doesn't scare me, as much as the entire engine is computer controlled anyhow, and the transmission and the ABS and traction control and everything else.

    Steve
    10 Chevy Traverse LT AWD
    02 Chevy Trailblazer LS (110K+ miles - loaded except for 4WD - WRECKED!)
    99 Chevy Cavalier LS (105K+ miles - commuter car)
    78 Chevy Suburban Silverado (454, 3/4 ton)
    62 GMC 3/4 ton Pickup (350 police interceptor)

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  3. #13

    Default Does A/C being on affect AFM?

    A friend of mine said that a mechanic told him, that if you run the A/C the engine will never go to 4 cyclinders. He says he's confirmed it with his DIC fuel mileage computer. How do you know when it's on or off?

  4. #14

    Default Afm

    Well I bought a Silverado with the active fuel management and am very impressed (so Far). The change from 8 cyl to 4 cyl is not at all noticable. If you put your DIC on instantaneous fuel reading it tells you hom many cylinders are working, and yes it still goes into 4 cyl mode with the AC on.

  5. #15
    Legend

    Join Date
    Feb 2008
    Location
    Red Wing, Minnesota, United States
    Posts
    3,356

    Default

    My dad has the 6.0 in his with AFM for his 07 NBS crew Z71 and he easily gets combined MPG of 18-19 and on long trips up north with the truck bed loaded with camping stuff and coolers of beverages and four people in the truck he can get 23-24 MPG even at 70MPH this is all falt and on the highway, but this is a very capable system and it has worked flawlessly for him for two years now in his truck
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual
    285/75/16
    ___________________________
    Jason

  6. #16

    Default

    I am new to this website and I also have a problem with afm, that is why I registered. I bought a Certified 2011 avalanche with just under 12,000 miles on it. When I am going 55 mph and keeping the speed even, it runs on 4 cylinders and starts vibrating through the steering wheel, seat, and gas pedal. Also when I do a right turn no stop, the truck acutally jerks when stepping on the gas to start speeding up. I have had it into the dealer about 5 times in the last couple of weeks and they feel the vibration and say its normal and they will not admit anything is wrong. I
    e-mailed GM and it seemed like they were going to do something, but today they called me and said nothing is wrong with it, that all afm engines vibrate. I know several people with this engine and they all say they shift flawlessly. I know they make scanners to shut it off, but my dealership and GM both said I should not disconnect it because it will void warranty. I traded in a Yukon and they have already sold it, so I am between a rock and a hard place. I wanted an Avalanche before they were gone, and its a great vehicle except for the vibration and jerking, but may have made a big mistake. Has anyone been able to shut off afm?

  7. #17

    Default

    I have it shut off in my truck. I noticed a lag when slowing to make a turn and than excelerating. Because of the lag the truck did "jump" a little. That is a major reason I purchased a Diablo inTune. it also help with the power and mpg's.





    2011 GMC Sierra SLE - 5.3 - 4X4 - Z71 - King Shock Level Kit - Body Color GMC grill emblem - 2 Tone Engine Cover, Rad Cover and Battery Box - Volant CAI - Tru Cool 40K tranny cooler - Sylvania ZXE bulbs Hi/Low -TriFold Hard Tonneau Cover- CoverCraft Seat Covers - Diablo inTune - GoRecon LED under rail lights - GoRecon LED White Lightning Tailgate Light Bar - Windows tinted to 45%- Kenwood DNX6990 - JL Audio C5-650 &650X- JL Audio Amp- Interco Truxus M/T 33x12.50x18

  8. #18

    Default

    I have an 08 GMC with afm. It gets 1 mpg better than my 94 Chevy did with the 350. Both Z71, 3.73, 4 speed auto. The 08 has 54k miles. The 94 had 212k. It will no doubt make engine work more expensive when the time comes, and from researching the net, it looks like afm causes some reliability problems. Google "afm lifter" or "afm oil consumption". Kinda scary. The only way of turning it off is a tuner. I don't trust it, but it seems to be the future. I once heard the quote "complexity is the enemy of reliability". Some truth to that, I imagine. The hemi has it also. And then there's the two turbos on the ecoboost. I'm not so sure the added technology is worth the added price tag, all in an effort to save fuel. Not sure how long you'd have to drive one to get that money back. And I have no doubt the added technology will cause some issues. Is a six speed auto more complex than a 4 speed? Yup. Are there more moving parts to fail? Yessir. Will it cost more to rebuild? Sure. I figure its the same way with an afm versus non afm engine. Now if I was getting 20 mpg, I'd say it was worth it. 16 mpg, not so much.

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