How does the Chevy AFM system work?
The Chevy Active Fuel Management (AFM) system is a sophisticated technology designed to improve fuel efficiency in certain Chevrolet vehicles. By temporarily deactivating specific engine cylinders under light-load driving conditions, the AFM system reduces fuel consumption without compromising performance. In this article, we’ll explore how this system works, its benefits, and what drivers should know about maintaining it.
What Is the Chevy AFM System?
The Active Fuel Management (AFM) system, also known as cylinder deactivation, is a feature found in many General Motors (GM) vehicles, including Chevrolet models. It allows the engine to switch seamlessly between full-cylinder operation and reduced-cylinder operation. For example, in a V8 engine equipped with AFM, the system can deactivate four cylinders when the vehicle is cruising or under a light load, effectively turning it into a V4 engine.
How Does the AFM System Work?
The AFM system relies on advanced engine control technology to monitor driving conditions and determine when cylinder deactivation is appropriate. Here’s a step-by-step breakdown of how it works:
- Monitoring Driving Conditions: The system continuously monitors factors such as throttle input, engine load, and vehicle speed to assess whether full power is needed.
- Deactivating Cylinders: When the vehicle is cruising or under a light load, the AFM system deactivates specific cylinders by closing their intake and exhaust valves. This is achieved using special lifters that collapse to prevent the valves from opening.
- Switching Back to Full Power: When more power is required, such as during acceleration or towing, the system reactivates the deactivated cylinders instantly, restoring full engine performance.
This seamless transition between modes is managed by the vehicle’s Engine Control Module (ECM), ensuring smooth operation without noticeable changes for the driver.
Benefits of the Chevy AFM System
The AFM system offers several advantages, making it a valuable feature for many drivers:
- Improved Fuel Efficiency: By deactivating cylinders when full power isn’t needed, the system reduces fuel consumption, especially during highway driving.
- Reduced Emissions: Lower fuel consumption translates to fewer emissions, contributing to a cleaner environment.
- Enhanced Engine Longevity: By reducing the workload on certain cylinders, the system can potentially extend the life of the engine.
Maintenance Tips for Vehicles with AFM
To ensure the AFM system operates effectively, regular maintenance is essential. Here are some tips for keeping your Chevy’s AFM system in top shape:
- Use the Recommended Oil: Always use the oil specified in your vehicle’s owner’s manual. AFM systems rely on proper lubrication to function correctly.
- Perform Regular Oil Changes: Timely oil changes are crucial to prevent sludge buildup, which can interfere with the AFM lifters.
- Monitor Engine Performance: If you notice unusual engine behavior, such as misfires or reduced performance, have your vehicle inspected by a professional mechanic.
- Consider an AFM Disabler: For drivers who prefer consistent full-cylinder operation, aftermarket AFM disablers are available. However, consult a professional before making modifications.
Conclusion
The Chevy AFM system is a remarkable innovation that balances performance and efficiency by adapting to driving conditions. While it offers significant benefits, proper maintenance is key to ensuring its longevity and reliability. If you have questions about your vehicle’s AFM system or need professional assistance, don’t hesitate to reach out to Kevin’s Autos for expert advice and service.
Frequently Asked Questions
Does AFM actually save fuel?
The fuel mileage is rarely affected allowing you to continue the same MPG you had before we deactivated the AFM to save thousands of dollars on repairs! Not to mention the hassle of being broke down on the side of the road or in a strange city on vacation.
Is there a class action lawsuit against GM for lifter failure?
Which vehicles are impacted? The GM engine valve-lifter class action lawsuit seeks damages for anyone who purchased or leased any 2014 to 2021 Buick (see also Buick lemon law), Cadillac, Chevrolet, and GMC vehicle equipped with a 5.3L, 6.0L or 6.2L V8 engine, and include the following cars: 2014 to present GMC Sierra.
What causes AFM lifters to fail?
We have found that most lifter faults are caused by oil pressure issues, or control issues. The AFM activation and deactivation is controlled by the Valve Lifter Oil Manifold or VLOM.
Can GM AFM be turned off?
An AFM Disabler is an electronic device that plugs into the OBD-II port, under the dashboard. It prevents the computer from switching over to 4 cylinder mode. It's a simple and effective way to turn off the AFM system. It will also improve the sound of the exhaust.
How much does it cost to replace AFM lifters?
Expect to pay somewhere between $1000 and $2,500 to get a professional to replace an engine lifter.
What year did Chevy 5.3 have lifter problems?
The models affected are Chevrolet Silverado trucks from 2016 to present and, most particularly the 2021 models with 5.3L and 6.2L engines.
Can you disable AFM with a scan tool?
For some drivers, these changes in engine performance are distracting or unwanted, which leads them to disable AFM altogether. While there are many ways to disable the system, using a scan tool is one of the most direct methods, and it can often be done without needing any extra devices or hardware.
How do I know if my range afm disabler is working?
On the latest AFM DISABLER Modules, the four blue lights are basically to indicate the unit is operating. THEY WILL GO OUT WHEN THE VEHICLE IS NOT RUNNING as described below (Power Saving). The lights are as follows: LED #1 - Power is ON and unit is AWAKE and vehicle is ready for commands.
What controls AFM lifters?
The veal ohm turns a solenoid off as oil flow stops spring. Pressure forces the latching pins out locking. The inner body to the outer body to engage the push rod.
How does the Chevy AFM work?
How does it work?
- 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.
