LML Duramax New CP4 Injection Pump – DDP NCP4-421

Replace a failed or worn factory CP4 with a brand-new Dynomite Diesel (DDP) NCP4-421 stock replacement injection pump. This is a direct bolt-in for 2011–2016 GM 6.6L Duramax LML engines that restores proper high-pressure fuel delivery and factory performance. No core charge required.

Key Features

• Brand new (not remanufactured) stock CP4 injection pump
• Direct OEM-style replacement
• Maintains stock power and fuel output
• No core charge
• 1-year unlimited mileage warranty
• Ready to install

Fitment

• 2011–2016 Chevrolet Silverado 2500HD / 3500HD
• 2011–2016 GMC Sierra 2500HD / 3500HD
• 6.6L Duramax LML (also fits applicable LGH applications)

Why Choose the DDP NCP4-421?

The CP4 is a known weak point on LML Duramax engines. When the original pump fails, it often sends metal debris through the fuel system. Installing a brand-new DDP unit gives you a clean starting point with factory-level performance and the peace of mind of a full manufacturer warranty—without the hassle or cost of a core return.

Important: If your original CP4 has failed internally, the entire high-pressure fuel system (rails, lines, and injectors) must be thoroughly cleaned or replaced before installing the new pump. Contaminated fuel will destroy a new CP4 quickly.