What lifters are AFM?

Lifters – AFM engines use special lifters for cylinders 1, 4, 6, and 7. They are taller and have special oil holes.

When did GM introduce AFM?

2005
General Motors first introduced its Active Fuel Management cylinder deactivation system in 2005. According to Lee, “Dynamic Fuel Management is a natural progression of the technology.”

Did GM do away with AFM?

General Motors is now building 2021 Chevy Silverado 1500 and 2021 GMC Sierra 1500 pickup trucks without Active Fuel Management (AFM) and Dynamic Fuel Management (DFM) technologies due to the ongoing global microchip shortage. The change is expected to continue through the 2021 model year.

What causes the lifters in an engine to go bad?

Hydraulic lifters can collapse, with no oil cushion to dampen the pounding from the tappet or push rod. Solid lifters can wear on their camshaft side, along with the camshaft lobes. Too much oil in the crankcase can cause oil aeration, or air bubbles, a condition when the crankshaft churns up the oil by direct contact.

How does GM AFM work?

The AFM system, or Active Fuel Management system, is used to limit the power of a GM 6-cylinder or 8-cylinder engine and help increase its fuel economy. The system itself is activated when the engine reaches certain perimeters, such as a cruising highway speed. This allows a 6-cylinder and 8-cylinder engine to run on only four cylinders.

How do AFM lifters work?

How Active Fuel Management (AFM) Works. When engine load is low: The computer sends a signal to the LOMA. The LOMA solenoids open. Oil flows to the special lifters through the AFM towers. The oil collapses the plunger inside the lifter. The collapsed lifters will not engage the pushrods and both valves remain closed.

How does Chevy AFM work?

The AFM works by turning off 4 of the 8 cylinders. The engine computer will turn off the 4 injectors and also turn the lifters off for those cylinders as well.