Interesting Article Segment I Found Regarding Disabling of AFM

Sierra Dan · February 11, 2019

By popular demand, I am posting this article I found in reference to a reported negative drawback from using a Range Device or similar AFM disabler.

My position on this issue is neither yea or nea! I will leave that up to the L83/L86 and previous 2007-2013 DOD engine experts.

An AFM Disabler is an electronic device that plugs into the OBD-II port, under the dashboard. It prevents the computer from switching over to four-cylinder mode.

It’s a simple and effective way to turn off the AFM system and provides the added bonus of improving exhaust sound.

NOTE: A disabler device should ONLY be used if the valvetrain is in good working order.

Engines with AFM use a high-volume oil pump. When you eliminate the AFM system, the extra oil is no longer needed.

Excess oil will be pushed out of the pressure relief valve into the oil pan. This will spray oil on the bottom of the cylinder walls which can cause oil burning, especially in high-rpm engines.

So I assume a catch can in unison with a Disabler is key to preventing this excess oil buildup?

Engine guys please chime in.

diyer2 · February 11, 2019

My 12 has had AFM disabled with a Range or used with the trans in manual for 2 years with no change in oil consumption.

Catch can added recently.

I recently put it in 6 gear and let it go into V4 mode to do a check.

Flawless operation.

I still believe it's the luck of the draw.

Edited February 11, 2019 by diyer2

SS502 · February 11, 2019

I run both the catch can and the Range so I would really like the opinion of those with more knowledge than myself...please speak your minds both positive and negative ?

I don’t have enough miles to give a good opinion.

Edited February 11, 2019 by SS502

Sierra Dan · February 11, 2019

Apparently, there is an AFM disabling Kit right around $700-$800 for a permanent solution.

I had never heard of this until reading about it in the article.

SS502 · February 11, 2019

7 minutes ago, Sierra Dan said:

Apparently, there is an AFM disabling Kit right around $700-$800 for a permanent solution.

I had never heard of this until reading about it in the article.

Yes there are...here is a 5.3 kit on Amazon

https://www.amazon.com/AMS-Racing-Management-Disable-engines/dp/B0758JXHJ4/ref=mp_s_a_1_2/147-0342472-6383845?ie=UTF8&qid=1549911363&sr=8-2&refinements=p_n_condition-type%3A6461716011&pi=AC_SX236_SY340_QL65&keywords=gm+afm&dpPl=1&dpID=41cszIeMhCL&ref=plSrch

While searching for this, I found an article that mentions changing out the oil pump to a regular volume pump...so this should be a very interesting thread.

JimCost2014 · February 11, 2019

Is this the engine build in the new Hot Rod magazine, article where they are talking about getting rid of the VVT system also?

1SLOW1500 · February 11, 2019

I calling BS or at least some BS.

The oil pan windage tray blocks the splash of oil to the crank. Also if this valve opens on a normal stock truck it is doing the same thing being disabled does. Yes we have 2 stage pump but that has much more to do with oil(not really oil but full synthetic) weight.

Yes there a full kits that manually close of the oil to dod. It is a must do on higher end build as bigger cams.

Now for catch cans. They have zero to do with this unless you are speaking of oil mist in the crank case "pressurized" conditions. Then that must is carried over to the intake manifold and fills it with oil that becomes burned into the heads and valve as well as pistons uper cycliner walls and exhaust.

So there are some truth.

flyingfool · February 11, 2019

don't forget particle build up on the filter that screens the oil going into the dod system

Sierra Dan · February 11, 2019

9 minutes ago, JimCost2014 said:

Is this the engine build in the new Hot Rod magazine, article where they are talking about getting rid of the VVT system also?

No.

JimCost2014 · February 11, 2019

2 minutes ago, Sierra Dan said:

No.

Is there a link on this post that I am missing?

Sierra Dan · February 11, 2019

https://www.onallcylinders.com/2017/11/30/how-to-delete-or-disable-active-fuel-management-afm-on-gm-engines/

tbarn · February 11, 2019

An automotive blog powered by Summit. Da ya think maybe Summit wants to sell the AFM elimination kits? Just sayin'.

nqabigt · February 11, 2019

5 years and 64,000+miles with range full time and no oil use

tbarn · February 11, 2019

Ha!! Should have clicked on the link. Takes you straight to Summit. Scammers!!

GMC #1 · February 11, 2019

New here, I have a 2016 Sierra and installed the Range when I picked up the truck with only 5 miles on it.... has been on it since... at 19800 miles started making a racket.. it's at the dealer to repair the AFM lifters and whatever else is broken inside there.

Had a catch can too but removed it before taking it in.