Cylinder Deactivation Issues?

Newell33 · February 17, 2017

Some say they notice it, and some say they don't. I believe that some trucks behave differently than others, and I also believe some people are considerably more in tune with their vehicles than others. My '14 was horrible, especially when combined with the clunking, hesitating, flair shifting transmission. It drove me back to a '13 2500HD as soon as it financially made sense. I won't purchase another new truck with any kind of cylinder deactivation.

Edit: By the way, when I shut off AFM both with the Range device my mileage was exactly the same. Ultimately when I shut if off with a tuner, my mileage increased by 1 mpg.

Edited February 17, 2017 by Newell33

sk · February 17, 2017

I may be in the minority but I LOVE my AFM. It's one of the reasons I bought the truck. It definitely improves fuel mileage and I don't notice it switching in and out. I do a lot of highway driving and once I get up to around 55-65 and am just cruising along it switches to V4. But it's nice to know I have the V8 available as soon as I need it (and I use that mode often too)!

Pearl2017 · February 18, 2017

If AFM allows GM to claim .1 MPG and keep producing my beloved V8 I'm not against it. As long as its still modifiable feature to those that choose not to have it. AFM off = Wonky shifting gone.

Grumpy Bear · February 18, 2017

I'm more than good with the AFM in my 2015 1500. No switching issues. No oil usage. No blues. Smooth as a kitten. Just clicked over 19K on the clock. 5993 miles, 240.677 gallons = 24.90 MPG. What's not to like?

JacobC1983 · February 18, 2017

I hated it. I could feel the surges at low speeds from the torque converter locking and unlocking with the transition from v4-v8. Got a range and the truck is MUCH more enjoyable to drive.

pickmeup · February 18, 2017

One simple button with a choice . Economy or Sport mode . I believe it would have saved many many complaints .

j-ten-ner · February 18, 2017

... I am probably the only one these forums who is 100% happy GM is using AFM and not 6cyl turbo@! ...

You're not the only one.

Because it's easier to turn of AFM than adding two cylinders.

so long

j-ten-ner

Donstar · February 18, 2017

I hated it. I could feel the surges at low speeds from the torque converter locking and unlocking with the transition from v4-v8. Got a range and the truck is MUCH more enjoyable to drive.

Did you take your truck in under warranty for service when it was having these problems? The transition from V4 - V8 is designed to be seamless. This was the case with my previous V8 and is with my current V6. If you did take it for service I am curious as to what the service adviser said about this issue.

JacobC1983 · February 18, 2017

Did you take your truck in under warranty for service when it was having these problems? The transition from V4 - V8 is designed to be seamless. This was the case with my previous V8 and is with my current V6. If you did take it for service I am curious as to what the service adviser said about this issue.

Nope. Following the AFM thread, I am not the only one with these issues.

Donstar · February 19, 2017

Nope. Following the AFM thread, I am not the only one with these issues.

Do I understand this to mean that you didn't get the problem fixed or have I misunderstood? I believe that this feature is designed to work seamlessly. I did a 125km return trip on the highway today and tried to determine when my truck was switching in and out of V4 mode. I could not do it without looking at the DIC. I would be sure to mention this issue to your service adviser while your vehicle is still under warranty. No need to put up with faulty components when under warranty!

Edited February 19, 2017 by Donstar

JacobC1983 · February 19, 2017

Taken from the AFM thread, fits my feelings perfectly and I have had a 2015 Sierra and 2016 Sierra while test driving at least 10 others...

"I think the debate regarding feeling the V4 is somewhat truck dependent and somewhat user feel. I think some trucks' V4 switching is a bit smoother than others. But I think some people are also more in tune with the changes that take place when the truck changes to V4...from the change in engine sound, the subtle back pressure that happens when it goes into V4, the change in the exhaust note, etc. I bet more often than not I can tell on any of your trucks when it's going into V4 mode without looking at the indicator on the dash. Sometimes it's hard to detect but most of the time I feel it and I also feel it way more in this truck than I ever did in my 2007."

Edited February 19, 2017 by JacobC1983

JacobC1983 · February 19, 2017

Do I understand this to mean that you didn't get the problem fixed or have I misunderstood? I believe that this feature is designed to work seamlessly. I did a 125km return trip on the highway today and tried to determine when my truck was switching in and out of V4 mode. I could not do it without looking at the DIC. I would be sure to mention this issue to your service adviser while your vehicle is still under warranty. No need to put up with faulty components when under warranty!

No offense... but I bet I feel it on your truck too.

Donstar · February 19, 2017

No offense... but I bet I feel it on your truck too.

Definitely no offence taken. If you could feel it on my truck and it demonstrates the same "surge" feel that you hate, I would be questioning you and not the truck! (lol) I don't doubt that your truck or others may have a faulty component. My point is for you to get it fixed if it is broken. Shortly after buying my truck, my front left signal light quit working. I didn't blame GM or hate my truck, I got it fixed. If you Google "left signal light not working" you get over 3 million hits. It is easy to find others that share a complaint. I doubt that you'd have a concern for this feature if it was working as intended!