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  • GM: Some 2021 Chevy/GMC Fullsize Pickups Will Lose Fuel Economy Due to Global Chip Shortage

GM: Some 2021 Chevy/GMC Fullsize Pickups Will Lose Fuel Economy Due to Global Chip Shortage

Truckmaker omitting fuel-management modules from 5.3L EcoTec3-powered rigs.

Mar 18, 2021
Add "semiconductor chips," well, a major, world-wide shortage of the microdevices and the negative impact it's having on the fullsize-pickup market, to the list of challenges that U.S. truck manufacturers have been facing since the start of the COVID-19 pandemic in 2020.
Last week, General Motors announced the lack of semiconductor chips, which is believed to be caused by a pandemic-driven increase in consumer-electronics sales, is forcing Chevrolet and GMC to build some 2021 5.3L EcoTec3 L84 V-8-powered Silverado and Sierra pickups without Dynamic Fuel Management modules, reducing the trucks' fuel economy by 1 mile per gallon.
The change, which is expected to run through the remainder of the 2021 model year, does not affect overall truck production for either brand, nor does it drastically impact GM's federal corporate average fuel economy numbers, which typically are met by using credits accrued in prior years or purchasing credits from other manufacturers.
"By taking this measure, we are better able to meet the strong customer and dealer demand for our fullsize trucks as the industry continues to rebound and strengthen," GM spokeswoman Michelle Malcho says. "We routinely monitor our fleet for compliance in the U.S. and Canada, and we balance our portfolio in a way that enables us to manage unforeseeable circumstances like this without compromising our overall (greenhouse gas) and fuel economy compliance."
In February, GM forecasted it could lose up to $2 billion in 2021 earnings due to the chip shortage.
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What Is Dynamic Fuel Management?

Introduced in 2019, GM's Dynamic Fuel Management (DFM) is cylinder-deactivation technology that enables engines to operate in 17 different cylinder patterns to optimize power delivery and efficiency at all speeds.
DFM is powered by a sophisticated controller that continuously monitors every movement of the accelerator pedal and runs a complex sequence of calculations to determine how many cylinders are required to meet the driver's requested torque. It can make this determination 80 times per second.
An electromechanical system deactivates and reactivates all 16 of the engine's hydraulic valve lifters, controlling valve actuation. The system uses solenoids to deliver oil pressure to control ports in the lifters, which activate and deactivate the lifters' latching mechanisms. When a cylinder is deactivated, the two-piece lifters effectively collapse on themselves to prevent them from opening the valves. When the cylinder is reactivated, solenoids send an oil pressure signal to the control ports on the lifters and the latching mechanism restores normal function, allowing the valves to open and close.
"The increased variability of Dynamic Fuel Management means the engine will operate more often with a reduced number of cylinders, which saves fuel across the board," says Jordan Lee, Chevrolet's small-block chief engineer.
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