HEUI, engine by engine: the oil-driven injectors

HEUI - hydraulically actuated, electronically controlled unit injection - is the fuel system of the 7.3 and 6.0 Power Stroke, the only engines on this site that ran it. The design inverts what most diesels do: the high-pressure oil pump (HPOP) pressurizes engine oil, not fuel, and each injector is its own pump, fired electronically and intensified hydraulically by that oil. The IPR valve regulates the pump's output, the ICP sensor reports the pressure, and the system lives or dies by oil: thin, aerated or leaking oil means an engine that cranks without firing, worst when hot.

This page groups what our records document, engine by engine: the high-pressure oil side - pump wear, the IPR, the STC fitting and standpipe leaks that bleed the pressure down - and the firing side - injector o-rings and stiction, the under-valve-cover harness, the 7.3's IDM and the 6.0's FICM - with provenance tiers, and the components on record with Dave's prices where Dave's lists them. Recalls whose own text names a part of the system: 05V-270 (6.0 Power Stroke, 2004-2005) - listed under the engine below. No other NHTSA safety recall on these engines names the HEUI system. The engines that came after and the other makes are listed at the bottom, with the pump their records name.

Every row is a published record - see /disclosure/

7.3 Power Stroke

• High-pressure oil pump wear / low ICP verified - common; no-start or long crank HOT, starts fine cold (oil thins)
• IPR valve failure / o-ring degradation aggregated - common; no-start or rough hot running; IPR duty pegged high
• Injector o-ring failure verified - common; blue/gray smoke at startup clearing as it warms
• Under-valve-cover harness (UVCH) failure verified - common; rough running / dead hole(s); misfire that comes and goes
• IDM (injector driver module) failure verified - occasional; dead/multiple dead holes or no-start with good oil pressure data

Components on record: AP63623, AP63624, PU7Z-9C968-B, PU7Z-9F838-A, AP63800AA, AP63801AB, AP63803AD, GZ-GA30001, GZ-GA35110, AP63414, F81Z-9D930-AB, 7.3L Power Stroke Valve Cover Connector Pigtails (Alliant AP0015 OBS / AP0016 99-03). Priced failures: /repair-costs/.

6.0 Power Stroke

• Fuel injector stiction / failure verified - common; rough cold idle or misfire that clears as the engine warms up
• STC fitting (high-pressure oil rail) failure verified - very-common; long crank / hard start when hot; may start fine cold
• IPR (Injection Pressure Regulator) valve failure verified - common; hard start, no-start, or stall at idle
• FICM (Fuel Injection Control Module) failure verified - very-common; hard start when cold; extended crank

Components on record: 4C3Z-9B246-F, 6E7Z-9A332-B - $236.67, 5C3Z-9C968-CA, 4C3Z-9F838-A, 6.0L Power Stroke Remanufactured Fuel Injector, stock HP (XDP XD470, 2003-2004) - $195.95, 6.0L Power Stroke Remanufactured Fuel Injector, stock HP (XDP XD471, 2004.5-2007) - $195.95, 4C3Z-12B599-ABRM, 6.0L Power Stroke FICM Power Supply (rebuild board, higher output) - recalls naming the HEUI system: 05V-270 (June 10, 2005). Priced failures: /repair-costs/.

Engines without HEUI (4)

• 6.4 Power Stroke - 2008-2010 - its documented failures are the DPF and the EGR cooler, not the fuel system
• 6.7 Power Stroke - the documented pump failure is the CP4.2 contamination cascade - see /cp4/
• Duramax LB7-LMM - its own failure record names the pump: the Bosch CP3
• 5.9 Cummins - P7100 (12v), VP44 (24v to 2002), Bosch CP3 (from 2003) - no HEUI anywhere in the line

Prices are Dave's Auto Center retail, the same as in his store (the only seller this site links); a component without a price is a record with no live listing - the part page says what is known. Open the failure page before buying anything, and mind the tier on every fact. Whether a recall is still open on a specific VIN is not known here - nhtsa.gov/recalls.