Failure mode - Ford 6.7L Power Stroke Diesel (Scorpion)

CP4.2 high-pressure fuel pump contamination cascade

Reliability tier: verified - verify before ordering, see /disclosure/

Symptoms

hard starting or a sudden stall, sometimes with no prior warning
fuel rail pressure DTCs P0087 (too low) / P0088 (too high), P0093 (large fuel leak detected), P008F (fuel/engine temp correlation)
metallic sheen or visible metal flakes in a cut-open fuel filter
loss of power that does not clear, often followed by a no-start

Compare with the other causes of the same sign on this engine: hard start, long crank or no-start (4 causes) · stalls or dies while driving · loss of power, limp mode or derate (5 causes) · metal in the fuel filter or oil

Root cause

The Bosch CP4.2 high-pressure pump (present on every 6.7L generation since 2011, per an aftermarket parts maker's 6.7L Power Stroke guide and independently per a parts retailer's 6.7L Power Stroke guide) was designed around European diesel's higher lubricity spec. Its cam-lobe/roller-lifter contact depends on a thin fuel film for lubrication; ultra-low-sulfur North American diesel, water contamination, or momentary fuel starvation can break that film down. Once metal-to-metal contact starts, the pump grinds itself apart and pushes fine metallic debris downstream under extreme pressure, contaminating the rails, all eight injectors, and the return system before the truck sets a code or dies. The same pump family (CP4/CP4.2) is the documented failure point on Ram 2019+ and the GM LML Duramax (the L5P switched to a Denso HP4) - this is a cross-platform Bosch architecture issue, not Ford-specific engineering.

Diagnosis

cut open the fuel filter and inspect for metallic debris before doing anything else - its presence changes the whole repair scope
review rail-pressure command vs actual during cranking; pressure that will not build implicates the pump or pressure-control valve
rule out the low-pressure supply side (lift pump, filters - see Low-pressure fuel supply weakness (lift pump, filters, water-in-fuel)) before condemning the high-pressure pump
a positive metal-in-filter finding means the injectors and rails must be treated as contaminated, not just the pump

Fixes

full fuel-system contamination kit: new/reman high-pressure pump + full injector set + rails + high-pressure lines + filters + seals in one job - replacing only the pump on a confirmed contamination event guarantees a repeat failure ()

preventive CP4 disaster-kit install (reroutes pump case return to the tank side instead of the injector feed, so a future pump failure drains to the tank instead of contaminating injectors) - insurance, not a repair for an already-failed pump ()

6.7L Power Stroke CP4 Disaster Prevention Bypass Kit, Gen2.1 (S&S Diesel Motorsport)

Prevalence

common

Parts for this repair run about $2,100-$7,600: see them next to the other repairs on this engine in repair costs.