By Joe McDonald
Executive Vice President of Sales
Jasper Engines and Transmissions
In the automotive aftermarket, our responsibility is simple: provide solutions that work. At Jasper Engines & Transmissions, we constantly evaluate where original equipment designs may be creating challenges for independent repair facilities and fleet operators. One of the most significant examples of that over the past decade has been the failures related to Active Fuel Management (AFM) and the latest GM design, Dynamic Fuel Management (DFM) systems in GM LS and LT engines.
Several years ago, our engineers, along with our New Product Department led by Brad Boeglin, began noticing a troubling pattern. Independent repair shops were seeing repeat failures in engines equipped with these cylinder deactivation systems, particularly in lifters. Our goal was to develop a reliable parts-only solution that would keep these engines in service without recurring problems.
Initially, we attempted the obvious solutions. We installed brand-new AFM lifters and replaced the Lifter Oil Manifold Assembly (LOMA) boards. However, despite these efforts, engines continued to fail—sometimes even within our warranty period. What we were experiencing internally was consistent with what shops and fleets across the industry were reporting. The failures weren’t isolated incidents; they were systemic.
Our engineering team dug deeper into the issue and discovered that the root cause wasn’t simply worn components. The failures were often tied to mistimed events within the AFM/DFM control system itself. In other words, the problem wasn’t always within the engine hardware—it was the control strategy interacting with the mechanical components in a way that created repeated failures.
Once we understood the root cause, the path forward became clear. The only long-term, reliable solution was to eliminate the AFM/DFM system entirely.
That realization led our engineers to develop a comprehensive AFM/DFM delete package for our remanufactured engines. The solution incorporated non-AFM lifters, lifter retainers, a non-AFM camshaft, and a valley plate without solenoids. Equally important, we included a tuning device designed to remove AFM/DFM commands and solenoid codes from the Engine Control Module (ECM). By addressing both the mechanical and electronic sides of the system, we were able to eliminate the root cause of these failures.
Of course, modifications that affect the valvetrain and ECM can potentially influence emissions and fuel economy. Because of that, we knew regulatory compliance was essential. We partnered with the SEMA Garage to navigate the approval process and ultimately secure a CARB Executive Order. This approval allows our AFM/DFM delete engines to be legally sold in all 50 states.
The response from the marketplace has been remarkable. Today, AFM delete engines account for approximately 75–85 percent of our LS and LT engine sales—far surpassing demand for stock AFM configurations.
For independent repair shops, this solution eliminates the frustration of repeat failures and protects their reputation with customers. For fleet operators, it means improved reliability, less downtime, and greater confidence in the longevity of their vehicles.
At JASPER, our mission has always been to support the professionals who keep America moving—independent repair shops, installers, and fleet operators. The AFM/DFM delete program is a perfect example of how listening to the market, applying engineering expertise, and committing to compliance can result in a better solution for everyone involved.
In the end, it’s not just about fixing an engine problem. It’s about delivering reliability, protecting the businesses that depend on us, and continuing to strengthen the independent automotive aftermarket.
