AFM disabler

[wsteele]

My 2007 Yukon had a low idle miss at 93K miles on the meter. The cylinder with the miss had a really fouled plug. It had been using about a quart of oil every 2K miles or so, which I assumed was worn rings.

To diagnose the miss, the dealer started with the PCV, moved to the down rev valve cover (which they swapped out along with a decarbonization procedure) and eventually ended up replacing all eight pistons, rings, etc. GM stepped up with the parts and my dealer did me a good turn on the labor, so I got fixed what seems to be an AFM related design issue, pretty inexpensively.

Fast forward a few years and 30K miles and the engine still runs like a top, no oil consumption between oil changes, etc.

The more I read about the AFM issue, the more I am thinking a couple hundred bucks to shut AFM off (with a Range Tech ODB plug) even though I have the updated valve cover, new pistons/rings, etc., seems like a small price to pay to avoid this issue completely say 70K down the road from here.

Opinions on the above logic are greatly appreciated.

 

[Dustin Jackson]

@wsteele I have been using the Range AFM disabler for about a year without a problem. I don't think that using it prevents it from having AFM related engine damage, I am using it just to keep it in V8 mode. Maybe people with more knowledge can chime in but I think the proper way to avoid AFM related problems is to replace all AFM components with non AFM ones.

 

[wsteele]

@wsteele I have been using the Range AFM disabler for about a year without a problem. I don't think that using it prevents it from having AFM related engine damage, I am using it just to keep it in V8 mode. Maybe people with more knowledge can chime in but I think the proper way to avoid AFM related problems is to replace all AFM components with non AFM ones.

Thanks for your input. I think deleting all the AFM components (lifters, cam, etc) is probably more than I want to undertake at this time. I was under the impression forcing it to stay in V8 mode would address any possible AFM related damage down the road. Sounds like I have to keep reading.

 

[Foggy]

Disable the AFM will help with longevity... The less/least it activates
the afm lifters, the less likely they will seize up in the lifter "case"..idk what
it's actual name is.. So YES, it's a great idea to at least deactivate it

 

[wsteele]

Disable the AFM will help with longevity... The less/least it activates
the afm lifters, the less likely they will seize up in the lifter "case"..idk what
it's actual name is.. So YES, it's a great idea to at least deactivate it

Thanks for the input. That was what I was reading about it.

 

[Geotrash]

Keep in mind that when the system isn’t active, the AFM lifters behave just like regular roller lifters, so while they could still fail in the ways that a regular lifter could, they won’t fail in transition between active/inactive, which is how AFM lifters normally stick and fail.

I just removed the AFM system from my 2012 mechanically with a new cam and lifters, and based on my experience and some of the problems I ran into, I would just keep running the range device or a black bear tune if I had it to do over again.


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[rockstar143]

That last set of posts really help a person out...thanks for that.
Just put the range on our 2015 LTZ for peace of mind...I always felt the
vehicle seemed a bit confused about shifting when it must have transitioning
from 4 to 8 when you get on it.

 

[wsteele]

Keep in mind that when the system isn’t active, the AFM lifters behave just like regular roller lifters, so while they could still fail in the ways that a regular lifter could, they won’t fail in transition between active/inactive, which is how AFM lifters normally stick and fail.

I just removed the AFM system from my 2012 mechanically with a new cam and lifters, and based on my experience and some of the problems I ran into, I would just keep running the range device or a black bear tune if I had it to do over again.


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Interesting and very helpful. If you have a thread outlining your experience with the mechanical AFM delete, I would love to read it. My search skills on forums really suck.

I mulled an AFM delete changing the cam and lifters, but in the end decided maybe using the Range device will get me mostly to the other side with this original engine and when the time came for a reman, maybe get an AFM deleted option at that time.

 

[Geotrash]

You bet. The whole saga is right here, and is still ongoing:

https://www.tahoeyukonforum.com/threads/2012-yukon-xl-denali-6-2l-cam-swap-thread.121671/

With a cam swap that includes AFM delete, it's like pulling a piece of tinsel out of a cat's butt: you keep pulling and find a bunch of other shit that needs cleaning up. You have to pull the heads to get the lifters out, and then while you're in there you might as well replace the timing chain and tensioner. But to do that you have to pull the oil pan, so you might as well replace the oil pump too, etc, etc, etc. And because you touch so many things, the chances of problems occurring as a result of the process go up. But on the upside, you learn A TON, and will never need to fear digging deep on one of these trucks again.

 

[gooffeyguy]

Some earlier models (07-08?) came from the factory with AFM hardware in the engines but it was disabled in the factory tuning.

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