As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE BLEED AIR VALVE 'OFF 'LIGHT NOT ON WITH SWITCH 'ON' & ENG RUNNING. DUCT PRESSURE WAS NORMAL. AFTER LT ENGINE START BLEED REMAINED OPEN, ONLY HAD 10 PSI DUCT PRESSURE, HAD TO TURN OFF BLEED TO STA. PRSOV VALVE REPLACED IAW AMM. ON ENG RUN IAW NEW PROCEDURE FOUND PRSOV OFF. STAYED ON WITH ENG RUNNING.