General Motors employs a number of different technologies to boost fuel economy, but one of these technologies, namely Active Fuel Management (AFM), has nearly been phased out from the 2022 Silverado engine lineup.
For those readers who may be unfamiliar, Active Fuel Management Cylinder Deactivation technology, or AFM for short, works to reduce fuel consumption by “shutting down” engine cylinders under light driving conditions. Given maximum engine power is not required during the majority of everyday driving, AFM works to deactivate engine cylinders when they are not needed, such as when cruising on the highway, thus saving on fuel. When more power is needed, the cylinders are reactivated.
The 2019 Chevy Silverado 1500, which marked the launch of the completely overhauled fourth-generation for the light-duty pickup on the GM T1 platform, offered three engines outfitted with AFM technology, while two engines had a related technology known as Dynamic Fuel Management (DFM). Meanwhile, the 2014 Chevy Silverado overhaul (K2 platform) had AFM on all three engines.
Now, however, with the introduction of the fully refreshed 2022 Silverado, only one engine is outfitted with AFM, namely the turbocharged 2.7L I4 L3B gasoline engine. To note, the turbocharged 2.7L I4 L3B gets a big torque boost for the 2022 model year, up to 420 pound-feet, a 20-percent increase compared to the 348 pound-feet produced previously.
The other three engines in the 2022 Silverado lineup, including the naturally aspirated 5.3L V8 L84 gasoline engine, the naturally aspirated 6.2L V8 L87 gasoline engine, and the 3.0L I6 LM2 turbodiesel Duramax, do not feature AFM. The L84 and L87 both feature DFM, while the 3.0L I6 LM2 does not feature either AFM or DFM.
With this in mind, it becomes apparent that AFM is slowly going away from the Silverado engine lineup. In its stead, the engine lineup is adopting either DFM, or, as is the case for the LM2 diesel, nothing.
Check out the table below for a summary of AFM and DFM technology incorporation for the last several model years of the Chevy Silverado, including the fully refreshed, T1-based 2022 Silverado:
| K2 | T1 Launch | T1 Refresh | |
|---|---|---|---|
| LV3 | AFM | AFM | - |
| L3B | - | AFM | AFM |
| L82 | - | AFM | - |
| L83 | AFM | - | - |
| L84 | - | DFM | DFM |
| L86 | AFM | - | - |
| L87 | - | DFM | DFM |
| LM2 | - | - | - |
| Total AFM | 3 | 3 | 1 |
| Total DFM | 0 | 2 | 2 |
| Total FM | 3 | 5 | 3 |
To note, some 2021 and 2022 Silverado models that normally would come with AFM or DFM are not equipped with either feature as a result of the ongoing global microchip shortage, as GM Authority covered previously.
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Comments
Well DFM is the successor, so this makes sense. And the diesel would likely suffer higher emissions if it dropped cylinders
They’ve demonstrated DFM/skip-fire on large diesels, but the benefit is much less. It’s mainly for emissions there. Basically diesels don’t need a throttle and already have large intakes, so you don’t save much fuel from cylinder deactivation. Diesels simply put less fuel in the cylinder under light-load, they don’t need to maintain a constant air-fuel ratio like gas engines do.
You’re right. I thought about it completely backwards
Purpose of cylinder deactivation in diesels is to keep the exhaust hot. Cummins is testing with Tula Tech to put DFM on their engines. Cummins thinks they can eliminate regen cycles (which would actually save a ton of fuel) regen is basically injecting additional fuel into the exhaust for people not familiar with the system to heat up the particluant filter enough to burn off soot. If you shut down cylinders and keep the exhaust hot already, no need to heat up the filter.
Yup^^^
If deactivate to have full time 8 acyl, does it void your warranty?
The person that gave you a Thumbs Down on that statement really needs to be educated on that matter.
Please explain how shutting down cylinders helps keep the exhaust hot? Are remaining cylinders run richer or something?
AFM is junk!!! I shut it off on my ’14 GMC Sierra and my mileage went up
It is funny when people flat out try and lie to strengthen their view point. It has shown to increase mpg 5-8% in independent tests. So shutting off a tech that saves fuel and then your mpg goes up, physics say otherwise. Let me guess, you at more Sugar and junk food and lost weight too?
It isn’t junk when it’s reliable and works. A few have had problems but that is in the decimal percent, those just try and make mountain out of mole hills with a ton of fake news noise.
Depends on how you drive. If you drive in a way your engine stays in V8 mode, turning it off won’t change a thing. That’s what I like about DFM. V4,V6, V17/32nds when you need it. Allows for more precise saving and instantaneous V8. Wish they would add it to the 6.6 HD. That engines big enough the pumping loss is looking significant.
Decimal percent until it happens to you and GM takes you for a ride. AFM is junk and GM knows it.
Decimal percent when you do the math and it comes out to be in the millions of trucks that have engine failure due to AFM. GM has been under reporting this for years.
2014 GMC Sierra SLT 115K miles and need to replace valves, pushrods, camshaft etc. now. It is garbage.
Your right it’s garbage and cutting peoples a lot of money, but GM don’t care they just keep on making more and selling them to us
My 2014 Silverado started ticking when going into V4 so I deactivated AFM and my mileage went from 17.2 mpg to 16.9 mpg tested over 3000 miles. Not a significant change.
I turned AFM off in my old truck and my fuel economy did not change.
It’s junk technology driven by government demands for higher fuel efficiency via CAFE. The consumers don’t want it. It ruined one of the best engine lineups available.
And I’m sorry to hear that the 2.7L is infected with it. That was a promising engine. It’s too bad that it’s a no-go now.
Depends how you drive. I turned it off in my truck too, but if you cruise at a reasonable speed the truck is under low load so it was frequently in V4. If you drive 70-75mph then there is too much load on the engine to drop into V4 and still provide the power to maintain the speed. I’d say I lost about 10% efficiency.
I’ve been driving with a tune on my 5.3 for about 3 years now, I’m curious to reflash the stock ECU tuning back to see how sluggish the truck actually was now that i’m fully accustom to the tune
You say what you want about the fuel systems on the Silverado. I drove from Virginia to Middle Georgia. I got 27.8 mpg over 479 miles.
Yes Mark-
You cannot get that king of mpg with the AFM turned off. The Silverado V8s do as well the the Eco-Boost (on the highway) -and you still have a V8!
My 2019 Silverado with the L82 has AFM, mileage is good but I’m not a fan of the little buck or jerk you feel at each AFM event, although minor I still notice it, will not miss that feature.
If the majority of Auto Manufacturers nationwide are suffering just to get new vehicles to dealerships just so that they can come up with microchips that will program a vehicle to meet more stringent CAFE standards, then I say do without it for the time being, I could agree with Trump on one issue when it came to this topic and he saw the writing on the wall and new that it would do harm more than good and decided to roll back the”EverChanging” emissions standards that most Auto and even Rail manufacturers could not keep up with. If Biden had any common sense, he would have left it alone for the time being and there would be plenty of new vehicles in the Parking Lots of Dealerships right now.
Mighty BIG IF, if biden had any sense it would be a miracle. I’d be willing to bet he has to wear diapers because he can’t tell when it’s time to piss.
“If Biden had any common sense” ….well, he’s proven over and over, again and again that he has zero “common sense” and zero intelligence. That’s what comes from being a life-long Politician that never held a job. The yet-to-be-answered-question is: just who or what is pulling this Puppet’s strings !
GM makes junk. Only an idiot would buy a GM
AFM is junk. I had to deactivate on my 2011 silverado because of lag. So much happier with a tune an intake and an exhaust. V8 Power all the time. Also went with a pedal commander to reduce the electric throttle response lag. Highly recommend.
Jim
Would someone enlighten me about the difference between AFM and DFM? I don’t know which I have. I have a 2018 Silverado LTZ with a 6.2 liter V8. The cylinders deactivate. I’ve been up to 24 mpg on the open road. It seems to be working for me.
I DON’T KNOW THE DIFFERENCE BUT IT WORKS FOR ME! YES I HAVE A 2018 6.2, ALL I DID WAS PUT HEADERS, COLD AIR INTAKE AND A DYNO TUNE. IT DEPENDS ON THE FOOT, OUT ON OPEN ROAD I USE CRUISE CONTROL WHERE I CAN AND WHEN I CAN.
They can have the chip out of my 2010 gmc Sierra I would gladly give it to them . I hate the afm crap in it makes the truck jerk when it comes on and goes off not to mention the lag between v4 to v8 . Makes me wish at times that I had kept my old 2000 Silverado with the lm7 without the afm crap !
AFM/DFM is to the V8 motor what CCC was to carburetors. The last gasp of a dying technology. Digital fuel injection was the future and everyone knew it. The future “engine” is an electric motor without all this Mickey Mouse nonsense bolted onto it to try and obtain reasonable power AND mileage.
Spoken by a guy who loves his old V8 truck as much as anyone.
Yeah, it may be a full 10 years before you can’t even order a V8 gasser anymore, and 20 before diesels die too, but the writing is on the wall. Do drag racers even run carburetors anymore, or are they all fuel injected nowadays.
Took late, I’m done with GM. Had an ’08 5.3L that dumped the AFM lifters and ate the camshaft at 62K miles. Had it fixed on my dime. Put an AFM disabler in it and gave it to my son. He is still driving it and has over 150K miles.
I figured after 11 years GM had fixed the AFM lifter issue so I bought a 2017 5.3L.
Started to have misfires at 28K miles and the truck was just over the 3 year bumper to bumper. I have a very short drive to work. I read the codes with a P0300 misfire code before taking it to the Stealership . They took me for ride right up the arse. They totally knew what was wrong with the truck when I first took it in yet they told me it was miss firing due to bad fuel injectors and the repair would not be covered under the drivetrain warranty. I had all the injectors replaced on my dime. They gave me the truck back after keeping it a week. I drove it home with no problems. Get up the next morning and started it up and sure enough it throws the same code P0300. The Stealership told me, oh it’s the left bank lifters are bad. Never gave me my money back on the injectors, but the lifters where covered under the powertrain. The Stealership was double dipping on me. Got my cash and GM warranty money. NEVER AGAIN GM. KEEP YOUR JUNK. AFM or DFM NEVER AGAIN.
AFM and DFM cause more problems than their worth. They have lifter, and pushrod issues. Simplicity is the key to reliability.
Get an F 150 5.0 and don’t look back.