Eliminate the #1 failure point in your LML Duramax and build with confidence.

The factory CP4.2 high-pressure fuel pump is widely known as the Achilles’ heel of the 2011–2016 LML Duramax. When it fails (and they fail often), it typically sends metal debris through the entire high-pressure fuel system, taking out expensive injectors, rails, and lines in the process.

S&S Diesel Motorsport — the leader in common-rail diesel injection — solved this problem by replacing the problematic CP4 with a proven, bulletproof CP3 pump. This Competition / Tuning Required version is built specifically for high-performance off-road and competition trucks that have had emissions equipment deleted.

Key Benefits

• Replaces the failure-prone CP4.2 with a far more reliable CP3 platform
• Engineered for serious horsepower — supports fueling from 500 hp up to 1,400+ hp (depending on pump configuration and supporting mods)
• Internally modified S&S CP3 pumps deliver excellent fuel volume and pressure even at high RPM — critical for competition use
• Removes the risk of catastrophic CP4 failure and the massive repair bills that come with it

What’s Included

• S&S modified CP3 high-pressure fuel pump (built from a brand-new Bosch LBZ-based core)
• Custom mounting bracket and all necessary hardware
• High-quality fuel line adapters and tubing
• Wiring harness extensions for clean installation
• Calibration data sheet to assist your tuner

Important Requirements & Notes

• Tuning is required for proper operation and performance
• Off-road / competition use only
• Professional installation and custom ECM tuning strongly recommended

Fitment: 2011–2016 GM 6.6L Duramax LML (Chevrolet Silverado / GMC Sierra 2500HD & 3500HD)

Whether you’re building a dedicated drag truck, sled puller, or high-horsepower off-road Duramax, this S&S CP3 conversion kit gives you the reliability and fueling capability your competition engine demands — without the constant worry of CP4 failure.