Ford Power Stroke Injection System History: 1994 to Present

1994.5–2003: 7.3L Power Stroke – HEUI Injection

• System: HEUI (Hydraulically actuated, electronically controlled unit injectors)
• Fuel Control: Oil pressure-driven injectors controlled by a high-pressure oil pump (HPOP)
• Strengths: No high-pressure fuel pump required. Mechanically durable.
• Weak Points: Injector o-rings, camshaft position sensor failures, HPOP leaks. Susceptible to cold-start issues if oil quality or pressure drops.

2003–2007: 6.0L Power Stroke – HEUI (2nd Gen)

• System: Advanced HEUI with more precise electronic control
• Changes: Higher oil and fuel pressures. Improved injection timing and emissions control.
• Known Issues: FICM (Fuel Injection Control Module) failures, sticking spool valves, oil cooler clogs impacting injector performance.
• Notes: HEUI system reached its limits in this application. Reliability dropped significantly without proper maintenance.

2008–2010: 6.4L Power Stroke – Common Rail (Siemens)

• System: High-pressure common rail with Siemens piezoelectric injectors
• Fuel Pump: Twin-piston high-pressure pump
• Benefits: Multiple injection events, cleaner emissions, more power
• Issues: Injector tip coking, fuel dilution, and injector stiction. High-pressure leaks could cause fuel in oil.
• Tuning Sensitivity: Poor tuning often led to over-fueling and early injector failure.

2011–2014: 6.7L Power Stroke – Bosch Piezo Common Rail

• System: Bosch high-pressure common rail with piezo injectors
• Fuel Pump: Bosch CP4.2
• Pressure: Up to 29,000 PSI
• Strengths: Precise injection control, improved emissions, quieter operation
• Weaknesses: CP4.2 prone to failure, potentially contaminating entire fuel system. Injectors were expensive to replace.

2015–2019: 6.7L Power Stroke – Bosch Solenoid Common Rail

• System: Bosch common rail with solenoid-style injectors (replacing piezo)
• Why the Change: Solenoid injectors proved more durable and less sensitive to fuel quality.
• Improved Reliability: Fewer failures and better longevity. CP4 pump still a known concern.

2020–Present: 6.7L Power Stroke – Bosch Updated Solenoid System

• System: Bosch common rail with next-gen solenoid injectors
• Fuel Pump: CP4 until mid-2021, then transitioned to DCR (Direct Control Rotary) high-pressure pump
• Injection Events: Up to 8 per cycle
• Benefits: Better cold starts, emissions compliance, more responsive throttle
• Reliability: Most durable and refined Power Stroke fuel system to date

Power Stroke Injector System Comparison Table

Engine	Years	Injection Type	Pump Type	Known Issues
7.3L	1994.5–2003	HEUI	HPOP	Injector o-rings, HPOP leaks
6.0L	2003–2007	HEUI (2nd Gen)	HPOP	FICM, spool valves, oil-related issues
6.4L	2008–2010	Piezo CR	Siemens HP	Fuel dilution, stiction, injector tips
6.7L v1	2011–2014	Bosch Piezo CR	Bosch CP4.2	CP4 failure, high injector cost
6.7L v2	2015–2019	Bosch Solenoid CR	Bosch CP4.2	More reliable injectors, CP4 issues
6.7L v3	2020–Present	Bosch Solenoid CR	CP4 → DCR	Most refined and durable setup

Final Thoughts

The Power Stroke injection system has come a long way since the HEUI days of the 1990s. While Ford has battled challenges with injector longevity and fuel pump reliability, the latest generation offers smoother power delivery, better cold starts, and fewer failures. As with any diesel, proper maintenance and clean fuel are essential.

By: Adam