Failure mode - Ford 7.3L Power Stroke Diesel (T444E)

IPR valve failure / o-ring degradation

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

Symptoms

no-start or rough hot running; IPR duty pegged high
ICP erratic vs commanded
IPR screen found clogged with debris (pump wear or oil breakdown)

Compare with the other causes of the same sign on this engine: hard start, long crank or no-start (7 causes) · misfire, rough idle, hesitation or surging (4 causes)

Root cause

The IPR regulates HPOP output; its o-rings harden and the screen clogs with debris. Cheaper and more common than the pump itself - always rule in/out before HPOP replacement.

Diagnosis

scan IPR duty vs ICP actual (high duty, low pressure = IPR circuit or pump)
inspect the IPR screen when accessible - debris tells you the pump is shedding
replace o-rings / valve and retest before condemning the HPOP

Fixes

IPR o-ring kit / replacement IPR valve (fit new screen) ()

7.3L Power Stroke IPR Valve (OEM)

Prevalence

common

Parts for this repair run about $10-$630: see them next to the other repairs on this engine in repair costs.