2011–2016 Chevy GMC Duramax 6.6L LML CP3 Conversion Kit | CP4 to CP3 Injection Pump Upgrade

2011–2016 Duramax LML CP3 Conversion Kit — Replace the Factory CP4 Before It Fails

The factory CP4 injection pump on the 2011–2016 Chevy Silverado and GMC Sierra 2500/3500 6.6L LML Duramax is one of the most expensive weak points on these trucks. When a CP4 fails, it can send metal contamination through the high-pressure fuel system, potentially damaging injectors, rails, fuel lines, and other major components.

This CP3 Injection Pump Conversion Kit is designed to replace the unreliable factory CP4 setup with a proven CP3-style fuel system conversion. Whether you are building a stronger tow rig, upgrading for long-term reliability, or preventing a costly CP4 failure, this kit gives your LML Duramax the foundation it should have had from the start.

Important: This option is for the CP3 Injection Pump Conversion Kit. The CP3 pump itself is not included unless selected separately as an add-on or kit option.

Why Upgrade Your LML Duramax From CP4 to CP3?

The CP3 platform has a long-standing reputation in the diesel world for durability, consistent fuel delivery, and better reliability under demanding conditions. For LML Duramax owners, converting from CP4 to CP3 is one of the most common preventative upgrades because it addresses the weak point before it becomes a catastrophic repair bill.

This kit is built for owners who want peace of mind, stronger fuel system reliability, and a cleaner path to supporting future performance upgrades.

Key Features

• Fits 2011–2016 Chevy / GMC 6.6L LML Duramax
• Converts factory CP4 injection pump setup to CP3-style configuration
• Helps reduce the risk of costly CP4-related fuel system failure
• Supports improved fuel system reliability and consistency
• Includes required conversion hardware, lines, fittings, brackets, and installation components
• Ideal for towing, daily driving, work trucks, and performance-oriented LML builds
• Designed for a clean, reliable CP3 conversion without piecing together random parts

Kit Includes

This CP3 conversion kit includes the required supporting components needed to install a CP3 pump in place of the factory CP4 system, including:

• Fuel lines
• Required fittings
• Mounting brackets
• Hardware
• CP3 conversion-specific installation components

CP3 pump is not included unless selected separately.

Fitment

Make: Chevrolet / GMC
Model: Silverado 2500HD / 3500HD, Sierra 2500HD / 3500HD
Engine: 6.6L Duramax LML
Years: 2011, 2012, 2013, 2014, 2015, 2016

Best For

• LML owners wanting to prevent CP4 failure
• Tow rigs and work trucks needing better long-term reliability
• Duramax owners upgrading the fuel system before adding power
• Trucks already undergoing fuel system, turbo, or engine valley work
• Customers who want a proven CP3-style fuel system instead of relying on the factory CP4

Sasquatch Diesels Note

If you own a 2011–2016 LML Duramax, the factory CP4 pump is not something to ignore. A CP4 failure can turn into a full fuel system replacement, which is exactly why many LML owners choose to upgrade before it fails.

This CP3 conversion kit gives your Duramax a stronger, more reliable fuel system foundation and helps protect your truck from one of the most common high-dollar failures on the LML platform.