Active Fuel Management (AFM) and Dynamic Fuel Management (DFM) will not be available on certain 2021 model year Silverado 1500/Sierra 1500 pickups

redwngr · March 16, 2021

17 hours ago, f8l vnm said:

Sooooooo...are they going to give buyers a credit for false advertising on the MPG part who already bought theirs?

???

Article says they are changing the economy label on the ones they build without the module to run afm/dfm.

redwngr · March 16, 2021

22 minutes ago, econometrics said:

As is asked previously in this thread, I wonder if this means the engines will still be built with all of the AFM/DFM assembly pieces, but they will just live in the engine "deactivated"?

If so, I would not be so entirely sure that the engines will become more "problem-free"?

I've had my 5.3L with DFM for two years. I like it. It's fun getting 28mpg on a long road trip. And though they say the MPG difference - on average - is just 1mpg less, I doubt that in certain applications of cruise.

I read it as just the module to run it will be gone -- but more than willing to hear more info.

Can't imagine there is anyway they did full endurance testing on these engines with and without the mechanical parts to make dfm work.

Again, certainly interested in any more info/details available.

econometrics · March 16, 2021

31 minutes ago, redwngr said:

Can't imagine there is anyway they did full endurance testing on these engines with and without the mechanical parts to make dfm work.

Again, certainly interested in any more info/details available.

yeah, I think you're right. This was done on a computer / paper with the engineers, and quickly tested I'm sure.

MS3DALE · March 16, 2021

18 hours ago, f8l vnm said:

Sooooooo...are they going to give buyers a credit for false advertising on the MPG part who already bought theirs?

No, because the ones already out there have it, there is no false advertising.

lmentzel · March 16, 2021

There are AFM / DFM delete kits out that remove all the components and replace the valve lifters, rocker arms and valve cover. These factory parts are being changed often under warranty. So I’ll bet they are losing money big time on this..

Hopefully they are deleted.

lmentzel · March 16, 2021

As is asked previously in this thread, I wonder if this means the engines will still be built with all of the AFM/DFM assembly pieces, but they will just live in the engine "deactivated"?

If so, I would not be so entirely sure that the engines will become more "problem-free"?

I've had my 5.3L with DFM for two years. I like it. It's fun getting 28mpg on a long road trip. And though they say the MPG difference - on average - is just 1mpg less, I doubt that in certain applications of cruise.

Yeah seems cool until you start having valve train issues and blown PCV valves.

Then you realize how bad the truck performs when you hit the gas..

Down shift twice, engage 8 cylinders, up shift once, clunk 3 times, then it finally accelerates..

redwngr · March 17, 2021

And the story continues to change...

The folks at gm-authority webite now reporting that some trucks still get DFM/AFM.

https://gmauthority.com/blog/2021/03/here-are-the-2021-chevy-silverado-gmc-sierra-models-that-will-keep-afm-dfm/

Looks like the 10 speed 5.3 trucks will still have DFM, and the Custom Crew 4wd (with Custom max trailering) with the 6 speed still gets AFM

Checking the order guide, it appears that( so far at least) the 6.2 still gets DFM.

Trucks with AFM/DFM disabled will get RPO code "YK9 Not Equipped with Dynamic Fuel Management" .

Work Truck	5.3L V8 L82	6-speed automatic	No AFM
Custom Crew Cab 4WD (with BD1 Custom Max Trailering Package)	5.3L V8 L82	6-speed automatic	AFM
Custom (all other variants)	5.3L V8 L82	6-speed automatic	No AFM
Custom Trail Boss	5.3L V8 L82	6-speed automatic	No AFM
LT	5.3L V8 L84	8-speed automatic	No DFM
RST	5.3L V8 L84	8-speed automatic	No DFM
LT Trail Boss	5.3L V8 L84	10-speed automatic	DFM
High Country 2WD	5.3L V8 L84	8-speed automatic	No DFM
High Country 4WD	5.3L V8 L84	10-speed automatic	DFM

Sierra	5.3L V8 L82	6-speed automatic	No AFM
SLE 2WD	5.3L V8 L84	8-speed automatic	No DFM
SLE 4WD	5.3L V8 L84	8-speed automatic	No DFM
SLE 4WD	5.3L V8 L84	10-speed automatic	DFM
Elevation 2WD	5.3L V8 L84	8-speed automatic	No DFM
Elevation 4WD	5.3L V8 L84	8-speed automatic	No DFM
Elevation 4WD	5.3L V8 L84	10-speed automatic	DFM
SLT 2WD	5.3L V8 L84	8-speed automatic	No DFM
SLT 4WD	5.3L V8 L84	8-speed automatic	No DFM
SLT 4WD (with PDT SLT Premium Plus Package)	5.3L V8 L84	10-speed automatic	DFM
SLT 4WD (with PDW Texas Edition SLT Premium Plus Package)	5.3L V8 L84	10-speed automatic	DFM
AT4	5.3L V8 L84	10-speed automatic	DFM
Denali 2WD	5.3L V8 L84	8-speed automatic	No DFM
Denali 4WD	5.3L V8 L84	10-speed automatic	DFM

Edited March 17, 2021 by redwngr

econometrics · March 17, 2021

Weird. You would think they would keep the DFM on the A8 and skip the A10. IDK, I just figure that would keep the MPG closer having those 2 extra gears.

PunchT37 · April 14, 2021

On 3/16/2021 at 6:10 PM, lmentzel said:

There are AFM / DFM delete kits out that remove all the components and replace the valve lifters, rocker arms and valve cover. These factory parts are being changed often under warranty. So I’ll bet they are losing money big time on this..

Hopefully they are deleted.

All they have to do is use the lifters and valley plate off the current 6.6l LT motor.

waltchan · April 28, 2021

What about 4.3L V6? This one has AFM too, and is this the only one available with AFM? That's a big difference in fuel economy here. Going from V6 AFM to V8 w/o AFM available for ordering. Pick one only.

I actually got up to 39.7 MPG before in V4 mode mostly from 4.3L V6. I was the OP of this thread:

Got up to 39.7 MPG on highway from Laughlin, NV to Los Angeles, CA...296.4 miles driving straight... - 2014 - 2019 Silverado & Sierra - GM-Trucks.com

But that was in 2018 model last generation with RWD 3.24 axle instead of 3.42 today. The new 2019+ design will never reach up to 39.7 MPG, due to 3.42 today.

Edited April 28, 2021 by waltchan