The S&S Diesel Motorsport LML-CP3-CARB CP4 to CP3 Conversion Kit (With Pump) is the solution to the fuel system needs in your 2011-2016 GM 6.6L Duramax. The factory CP4.2 pump in the LML Duramax engine is commonly known to fail and in many cases it takes out the entire, very costly, high-pressure fuel system with it including the fuel injectors, fuel rails, and lines. S&S Diesel Motorsport engineered this CP3 conversion kit as a solution for this common failure point. This kit includes all hardware necessary to replace the troublesome CP4 pump with the bulletproof CP3 pump. Installing this kit requires no tuning changes and maintains factory emissions control equipment.