LML Duramax CP4 → CP3 Conversion Kit (2011–2016)
If you own a 2011–2016 LML Duramax, you already know the factory CP4 injection pump has a reputation for failure — and when it goes, it can contaminate the entire fuel system with metal debris. That means injectors, rails, sensors, and lines can all be affected, turning a single failure into a major repair.
This conversion kit allows you to replace the failure-prone CP4 with the proven and reliable CP3 pump setup — the same style pump trusted in earlier Duramax platforms and high-performance builds.
Why Convert to CP3?
✔ Improved reliability – Eliminates one of the most common weak points in the LML fuel system
✔ Fuel system protection – Helps reduce risk of system-wide contamination
✔ Performance potential – Higher-flow CP3 options support stock builds up to race applications
✔ Peace of mind – Built for durability under towing, daily driving, or competition use
What Makes This Kit Different
This kit is designed to integrate cleanly and safely:
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Utilizes the factory fuel line in the engine valley
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Avoids problematic flare-style connections that can leak
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Cleaner installation and reduced fire-risk concerns
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Supports factory fuel filtration
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Compatible with aftermarket lift pumps using the included ½" high-flow feed fitting and pre-molded hose
Fitment
2011–2016 Chevrolet Silverado / GMC Sierra 2500HD & 3500HD 6.6L LML Duramax
Pump Options
CP3 pump is optional
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Want more fuel? Select from higher-flow CP3 pump options for performance builds
Works for:
• Stock trucks
• Tow rigs
• Daily drivers
• High-horsepower street trucks
• Competition builds
Optional Installer Kit
Installer kit is optional and includes all gaskets and O-rings removed during disassembly, allowing you to replace wear items while everything is already apart — saving time and preventing future leaks.
Included
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CP3 Conversion Install Hardware
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High-flow fuel feed components
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Pre-molded fuel hose
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All necessary fittings and mounting components
Upgrading to a CP3 system is one of the most popular reliability and performance upgrades for the LML platform — protecting your fuel system while opening the door for future power upgrades.