CP3 Conversion Kit (2011-2016 Duramax LML)S&S Diesel Motorsport, the world leader in common rail diesel injection has developed a solution for CP4. 2 high pressure pump failures that have plagued the LML Duramax engine. The S&S solution is to remove the problem before it becomes a problem, by replacing the CP4. 2 with a tried and true, bulletproof CP3 high pressure fuel pump. CP4 high pressure pumps are the Achilles heel of the LML Duramax engine because of high failure rates, and commonly