What was found
ENGINE DUCT PRESSURES SPLIT DURING CRUISE WITH ISOLATION VALVE CLOSED AND BLEED SWITCH SELECTED ON. RECORD DUCT PRESSURES. LOCKED CLOSED RIGHT ENGINE HIGH STAGE VALVE AND REMOVED ELECTRICAL CONNECTOR FROM HIGH STAGE CONTROLLER. REMOVED AND REPLACED 14TH STAGE PILOT VALVE, RAN ENGINES, NO BLEED PRESSURE SPLIT AT IDLE OR CRUISE POWER SETTINGS. FOUND HIGH PRESSURE BLEED ON LEFT ENGINE NOT SWITCHING OVER, NO DEFECTS ON RT BLEEDS.