Can AFM be turned off?
Active Fuel Management (AFM) is a technology used in many modern vehicles to improve fuel efficiency by deactivating certain cylinders when full engine power is not needed. While this feature can save fuel, some drivers may wish to disable it for various reasons, such as improving performance or avoiding potential long-term engine wear. In this article, we’ll explore whether AFM can be turned off, how it can be done, and what you should consider before making this decision.
What Is Active Fuel Management (AFM)?
AFM, also known as cylinder deactivation, is a system commonly found in General Motors (GM) vehicles. It allows the engine to switch between full-cylinder operation and reduced-cylinder operation, depending on driving conditions. For example, during highway cruising, AFM may deactivate half of the engine’s cylinders to conserve fuel. When more power is needed, such as during acceleration, all cylinders are reactivated.
Why Would Someone Want to Turn Off AFM?
While AFM offers fuel-saving benefits, there are several reasons why a driver might want to disable it:
- Performance Concerns: Some drivers feel that AFM reduces the overall performance of their vehicle, particularly in terms of acceleration and responsiveness.
- Engine Longevity: There is a belief among some car enthusiasts that AFM can lead to increased wear and tear on certain engine components, such as lifters and camshafts, over time.
- Driving Preferences: Drivers who prioritize consistent engine performance over fuel efficiency may prefer to keep all cylinders active at all times.
Can AFM Be Turned Off?
Yes, AFM can be turned off, but it requires specific tools or modifications. Here are the most common methods:
- Using an AFM Disabler: This is a plug-and-play device that connects to your vehicle’s OBD-II port. It prevents the AFM system from activating, keeping all cylinders operational at all times. This method is non-invasive and can be easily reversed.
- Reprogramming the ECU: A more permanent solution involves reprogramming the vehicle’s Engine Control Unit (ECU) using specialized tuning software. This method disables AFM entirely but requires professional expertise and may void your vehicle’s warranty.
- Mechanical Modifications: For those seeking a long-term solution, mechanical modifications such as replacing the AFM lifters with standard lifters can be performed. This is a more complex and costly option, typically done during engine rebuilds or upgrades.
Things to Consider Before Disabling AFM
Before deciding to turn off AFM, it’s important to weigh the pros and cons:
- Fuel Efficiency: Disabling AFM will likely reduce your vehicle’s fuel economy, especially during highway driving.
- Warranty Implications: Modifying or disabling AFM may void your vehicle’s warranty, so check with your manufacturer or dealer first.
- Legal and Environmental Concerns: In some regions, tampering with emissions-related systems like AFM may be illegal. Ensure compliance with local regulations.
- Professional Assistance: If you’re not experienced with vehicle modifications, it’s best to consult a professional mechanic to avoid potential damage to your engine.
Conclusion
While it is possible to turn off AFM, the decision should be made carefully, considering your driving needs, vehicle warranty, and potential impacts on fuel efficiency and engine performance. If you’re unsure about the best course of action, consult a trusted auto repair professional. At Kevin’s Autos, we’re here to help you make informed decisions about your vehicle’s maintenance and performance. Feel free to reach out to us for expert advice!
Frequently Asked Questions
Can you turn off AFM?
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.
Does disabling AFM improve MPG?
Additionally, if you happen to spend all of your driving time in the range where the factor AFM V4 mode is the most efficient (and the V8 disabler turns it off), you will see an additional hit to the mileage (usually around 1 mpg).
Will disabling AFM void warranty?
They do not change the factory programming and therefore don't void warranty. However, it is recommended to unplug the device before taking your vehicle to the dealership to avoid any potential conflicts. There is no evidence that the device has been plugged in once it is removed.
Which AFM disabler is the best?
The Range Technology AFM Disabler is one of the most trusted devices for deactivating the AFM system in GM vehicles.
Can you disable cylinder deactivation?
Unfortunately, optimizing the system requires that we adjust the triggers that make us step from all cylinders to shut-off mode and back again. Looking at popular aftermarket tuning software options, there are several ways to disable the system, based on rpm, VSS, gear, voltage, run time, and more.
Can you get a Silverado without an AFM?
This is some pretty crazy new in the truck world! GM just announced they will be making 5.3 v8 without any AFM or DFM for the remainder of 2021. Yes that's right you will now be able to buy a brand new truck from GM without any fuel management systems shutting down cylinders! Full article - https://www.gm-trucks.c.
Does disabling AFM improve mpg?
Additionally, if you happen to spend all of your driving time in the range where the factor AFM V4 mode is the most efficient (and the V8 disabler turns it off), you will see an additional hit to the mileage (usually around 1 mpg).
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.
Why disable Honda VCM?
If the cylinder rings are not completely worn out, disabling VCM should reduce oil consumption on your vehicle. If excessive oil consumption is a new problem for your vehicle, the sooner you apply VCMTUNER the less wear and damage to your engine.
Can Honda cylinder deactivation be turned off?
I know you can buy a switch that by-passes it and essentially turns it off the cylinder deactivation system but it's not problem-proof and can cause error codes to pop-up. I haven't seen anyone mention that the S-VCM system can cause error codes to pop up, and that device has been around the block for a while.
