If you own a 2011+ 6.7L Ford Powerstroke, you've probably heard the acronym whispered in forums like a warning label: CP4. Here's what it actually means for your truck, and what your real options are.
What is the CP4, and why does it fail?
The Bosch CP4.2 high-pressure fuel pump was designed for European diesel standards, where fuel lubricity is higher than what's required in U.S. ultra-low sulfur diesel (ULSD). Run on U.S. fuel, the CP4's internal components can wear prematurely — and when they do, it doesn't fail quietly. It fails catastrophically, sending metal shavings through your entire fuel system: injectors, rail, lines, and sometimes the tank itself.
Why this matters more than most maintenance issues
A CP4 failure isn't a repair — it's usually a full fuel system replacement. Owners who've been through it report costs that can run well into five figures once injectors, lines, and the pump itself are all accounted for. Unlike most parts on this truck, this isn't a "fix it when it breaks" situation — by the time you notice symptoms, the damage is often already done.
Your three options, in order of investment:
- Prevent it. The Gen2.1 CP4 Disaster Prevention Kit adds high-micron pre-filtration and a bypass valve, so if the CP4 does start shedding metal, it's caught before it reaches your injectors. This doesn't fix the underlying design issue — it's insurance against the worst-case outcome.
- Convert to a DCR-style pump. The S&S Diesel CP4 to DCR Pump Conversion replaces the CP4's problematic design with hardware built for U.S. diesel fuel from the start — eliminating the failure mode entirely.
- Convert to a CP3. The SPE CP3 Conversion Kit swaps in the older, proven Bosch CP3 pump architecture — a bigger investment, but the most battle-tested solution on this list.
Bottom line: if you're daily-driving or towing serious weight, doing nothing is the riskiest option here. Even the entry-level prevention kit meaningfully changes your downside risk for a few hundred dollars.