Fuel Contamination Kits
A contamination kit is required after a 6.7L Cummins stops running—specifically due to a CP4 high-pressure fuel pump failure—because the pump fails catastrophically, sending microscopic metal shavings throughout the entire fuel system. This debris spreads through the lines, rails, and injectors, often requiring a complete system replacement to prevent the new components from immediately failing again. This is also the main reason the later year 6.7L Cummins trucks returned to using the trusted CP3 pump.
Why a Contamination Kit is Necessary:
- The "Grenade Effect": When the CP4 pump fails, it destroys itself internally, acting like a "grenade" that forces metal filings downstream at 26,000+ PSI.
- Irreparable Contamination: Simple flushing is usually inadequate, as microscopic particles embed themselves in components and are nearly impossible to fully remove, leading to repeated, costly injector failures.
- Full System Protection: Kits include new, OEM-quality parts—injectors, pumps, rails, and lines—to ensure no debris is left behind.