LML Duramax S&S CP4 to CP3 Conversion Kit – No Tuning Required

Eliminate the #1 reliability threat on your 2011–2016 LML Duramax with the S&S Diesel Motorsport CP4 to CP3 Conversion Kit. This complete kit replaces the failure-prone Bosch CP4.2 high-pressure fuel pump with a proven, durable CP3 — stopping metal contamination before it destroys your injectors, rails, and high-pressure lines.

Why Convert?

The factory CP4.2 is widely known as the Achilles’ heel of the LML platform. When it fails, it typically sends metal debris through the entire high-pressure fuel system, leading to extremely expensive repairs. The CP3 has a long track record of reliability and is far better suited for long-term durability.

Key Features

• No tuning required — Drop-in solution that works without ECM calibration changes
• Includes a new S&S-specified CP3 high-pressure fuel pump
• Complete hardware package: mounting adapter, high-pressure line, feed/return fittings and hoses, FCA extension harness, and all necessary hardware
• Designed for straightforward installation
• Significantly improved fuel system reliability and longevity

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

This is the competition/off-road oriented no-tune version of the S&S LML CP3 conversion. It is ideal for trucks that are used in off-road/competition applications where a no-tune drop-in is preferred.

Protect your LML from a costly CP4 failure and gain the peace of mind that comes with a bulletproof CP3.