Deleting GM Cylinder Deactivation

[deerefan]

Question for you guys-my dad has a regular mechanic he uses and for $300 he turned off the cylinder deactivation on his Avalanche. From what I read, this method of afm has some issues and I would like to turn it off in my wife’s 15 Yukon. The mechanic did it with some codes from GM, I am guessing through the obd port. Thoughts?

 

[LittleBill21]

thoughts on what? the way it was turned off, or the deactivation overall?

 

[kirkawilson]

I turned mine off 3 years ago using the VCM tuner https://www.vcmtuner.com/. It's a 2014 Honda Pilot, and I had excessive drive train vibration and poor acceleration response. Recently had to replace a defective motor mount that was likely damaged before installing the VCM tuner. It has worked great! Minimal vibration and noise at cruising speed and no noticeable gas mileage difference. My dealer would not turn it off, so I installed it myself. Took about 2 minutes. Just a variable resistor in the coolant temperature sensor circuit that fools the controller into thinking the car never reaches operating temperature setpoint. Temperature gauge still works, just points slightly lower than before installing the VCM tuner.

 

[s219]

You can buy a doo-hickey to defeat it for $50-200, plugs into the OBD port. May be specific to the year/model. Most of the older V4/V8 AFM systems are covered.

On my newer 2020 GMC truck, it has DFM (d=dynamic) and can run from 2-8 cylinders with all sorts of variations. I don't believe they have worked out a defeat for that yet, at least not when I looked around last year.

 

[ruffdog]

Get the Range AFM disabler if you want all cylinders...all the time. The early AFM vehicles had some issues but the design changed. The 2015 Yukon is past the redesign so don't worry about it. I have a 2013 and a Range but it is turned off most of the time.

AFM/DFM Disabler - Range Technology

 

[deerefan]

thoughts on what? the way it was turned off, or the deactivation overall?

If you have done it, how did it work etc

 

[ruffdog]

With the Range AFM disabler, the only difference I notice is it lessens the slight shudder when you barely roll on the gas. You can also put the shifter to M 5 and it will keep AFM from activating.

 

[5030]

Got rid of it on my wife's Burb with the Range (Holley) deactivator and it stays in the OBD port all the time unless I have my Autel scan tool plugged in.

I don't like it for a couple reasons. One, the shudder but more importantly, it dries out the non firing cylinders and eventually the motor starts using oil. It's a poor design, only used to get GM's CAFE up and nothing more.

It's a V8 and I like to sound of a V8 anyway. I can actually get better mileage manually by driving conservatively.

 

[PuffyC]

Weird, I have a 6.2l Chevy motor in one of my vehicles and I can never tell when it switches to 4 cyl vs 8. You'd only know by the tiny light that changes color in the dash.

 

[dodge man]

I disabled it with a tuner on my 2010 Dodge Challenger. It’s not 100% stock anyway and low miles and it drives better and sounds better with it off. It does work and it does save fuel. Not exact science on my part but I estimate it hurt my fuel mileage at least 5% and maybe as much as 10%.