Exactly what year did GM start using Active Fuel Management?
If you're trying to figure out what year did gm start using active fuel management , the short reply is 2005, but there's a lot more to the tale than just the single date upon a calendar. Whilst the branding "Active Fuel Management" (AFM) officially hit the particular market in the mid-2000s, General Motors got been flirting using the idea of shutting down cylinders to save gas with regard to decades. However, 2006 was the year they finally committed to the tech we recognize nowadays, starting with their particular mid-sized SUVs.
Before it had been called AFM, GM briefly used the term "Displacement upon Demand" (DoD). If you find someone arguing that it started in 2004 or 2005, they're both technically correct depending on regardless of whether they're looking with the production date or the model year. For the sake of many owners and technicians, 2006 will be the official kickoff with regard to this modern era of cylinder deactivation.
The early days of cylinder deactivation
To actually understand why GM proceeded to go this route within 2005, we have got to look back at their very first, rather disastrous try in the eighties. Back then, they presented the L62 V8-6-4 engine for Cadillac. It was supposed in order to be a revolution, letting a large V8 run since a V6 or a V4 with respect to the load.
The problem? The computers in 1981 were about mainly because powerful as the basic calculator. These people couldn't process the transitions fast enough, leading to jerky performance and enormous reliability issues. Many owners ended upward getting the system shut off by the dealer. GM tucked the concept away for more than 20 years until computer processing caught upward using their ambitions.
By the time the earlier 2000s rolled about, fuel economy specifications were getting tight. GM needed a way to keep selling their popular V8 engines in trucks and SUVs without getting hammered by fuel performance regulations. That's whenever the "Displacement upon Demand" project—later renamed Active Fuel Management—was dusted off plus polished to get a brand-new generation.
Which usually vehicles started using it very first?
The 2006 model year noticed the debut of AFM within the 5. 3L LH6 V8 engine . If you were purchasing at a Chevy or even GMC dealership back then, you should have got found this technology in the Chevy TrailBlazer EXT and the GMC Charge XL. These were the particular long-wheelbase versions of their popular medium sized SUVs.
Interestingly, the standard-wheelbase models didn't almost all get it best away. It had been the bit of a slow rollout. Simply by 2006, the tech expanded to more models, such as the Impala SS and the Monte Carlo SS, which used the five. 3L LS4 engine. It wasn't till the 3 years ago model year (the GMT900 platform launch) that AFM became the staple in the Silverado and Sierra pickup trucks. That's when the general public actually started taking notice—and when the problems started trickling within.
How the system actually functions
It's really pretty clever engineering, even if they have its critics. The goal of AFM is in order to turn an OF V8 in to a V4 when you're just cruising throughout the highway or coasting down the hill. By closing down four associated with the eight cylinders, the engine decreases "pumping losses, " which basically indicates it doesn't possess to work since difficult to pull atmosphere in to the cylinders that aren't doing any work.
The particular magic happens within the lifters. In a standard engine, the lifters are solid pieces of metallic that push the valves open. In an AFM engine, four of the cyl have special "collapsible" lifters. When the personal computer decides it's time to save fuel, it sends a sign to a solenoid the Valve Lifter Essential oil Manifold (VLOM) .
This particular manifold directs high-pressure oil into the particular special lifters, activating a locking pin number to retract. As soon as that pin is gone, the lifter just squishes just like a spring instead of pushing the device open. The regulators stay closed, the fuel injectors intended for those cylinders close off, and you're suddenly driving the four-cylinder truck. Once you step on the particular gas to pass someone, the oil pressure is launched, the pins locking mechanism back into location, and you're back to full V8 energy in about 250 milliseconds.
The pros and the (very real) cons
On paper, Active Fuel Management is a win-win. GM stated it could enhance fuel economy by anywhere from 5% to 12% based on how you drive. For a heavy Suburban or the Silverado, those extra miles-per-gallon add up over a year of commuting. Once the system is operating perfectly, the changeover is nearly seamless. Almost all drivers only discover a little light upon the dash that switches from "V8" to "V4. "
However, if you spend any time on truck discussion boards, you'll know that AFM isn't precisely beloved by everyone. The device introduced the few headaches that will plagued GM owners for years:
- Lifter Failing: All those fancy collapsible lifters are prone to getting stuck. When a lifter fails to "unlock" or "relock, " it can cause a nasty engine tick or the total misfire. In worst-case scenarios, that can even harm the camshaft.
- Oil Usage: Because the cylinders are deactivated but the pistons are still moving up and down, several engines developed issues with oil getting past the piston rings. This led to trucks "disappearing" a quart of oil every 1000 miles with no noticeable leaks.
- Vibration and Jingle: Several people are extremely sensitive to the particular change in engine harmonics. Once the vehicle drops to V4 mode, the wear out note changes. In the event that you've put a good aftermarket exhaust on your truck, this particular change can sound pretty funky—almost just like a helicopter hovering nearby.
The evolution into Dynamic Fuel Management
By 2019, GM decided that shutting lower exactly four cylinders wasn't precise good enough. They introduced Dynamic Fuel Management (DFM) . While AFM only had two settings (8-cylinder or 4-cylinder), DFM is far more sophisticated.
DFM can operate the engine in 17 different styles. It can run on two cyl, three cylinders, or even just one. It's constantly calculating how many "power strokes" it requires to sustain speed. It's a much smoother program and handles the particular transitions better than the initial AFM ever did, though the particular mechanical complexity is even higher.
Can you get rid of it?
Due to the reliability concerns, several owners of 2005 and newer GM vehicles look for ways to disable the system. There are two main ways individuals do this:
- Electronic Disablers: You can buy a little device that plugs straight into your OBD-II port. It basically "tricks" the computer directly into thinking the situations are never right to switch to V4 mode. This maintains the truck within V8 mode 100% of the time. It doesn't fix the mechanical poor points, however it prevents the lifters from cycling, which many believe extends their particular life.
- Mechanical Delete: This is the "nuclear option. " It involves tearing the particular engine down, changing the AFM lifters with standard ones, and swapping your camshaft and oil pump. It's costly, but it's the only way to truly "bulletproof" the engine from AFM-related failures.
Is it worth the particular worry?
Even though Active Fuel Management includes a little bit of a noticed reputation, it's worthy of noting that large numbers of these motors are on the street with hundreds of thousands of mls on them. The important thing, as with most things, is upkeep.
The particular AFM system depends heavily on essential oil pressure and essential oil cleanliness. If you're the type of person who pushes your oil modifications to 10, 000 miles, an AFM engine will give you trouble. The tiny passages within the VLOM and the locking pins in the lifters need clean oil to function.
So, while 2005 was the year GM started using active fuel management , it's a technology which has continued to evolve. Whether you enjoy it for the particular gas savings or even hate it with regard to the mechanical intricacy, it's an understanding feature of the modern GM V8 experience. If you're buying an utilized truck from that era, just create sure you check the service records—and maybe listen closely for just about any suspicious ticking sounds under the engine.