T444E (7.3 Power Stroke)

Navistar International built it, not Ford — the T444E, sold in Ford trucks as the 7.3 Power Stroke.

⚑ That is the whole reason to know its real name. Ford badged and sold it; International designed, built and serviced it, and the T444E designation finds the engineering, the rebuild specifications and a parts supply the Ford name does not. The same engine went into International's own medium trucks and school buses.

Its reputation is exceptional and largely deserved: an indirect-injection design with hydraulically actuated electronic injectors, understressed at its factory output, and routinely running very high mileages.

The injectors are the characteristic fault and they are oil-driven — so a hard start, a miss or a no-start on one of these is an engine-oil problem before it is a fuel problem. Oil viscosity, level and the high-pressure oil pump come before the fuel system in any diagnosis.

The 6.0 Power Stroke that replaced it is a different engine with a far worse reputation, and conflating the two is the commonest error in Ford diesel discussion. The 6.9 IDI before it is different again — mechanical, no electronics at all — and both sit in the same trucks a few years apart.