What was found
DURING START OF NR 3 ENG CREW RECEIVED LVL2 AIR SYS 3 PRESS LO. ALSO FUMES IN COCKPIT. RAN CHECKLIST. DEFERRED APU AIR M427248 ASSIGNED. RAN ENGINES SEVERAL TIMES. NO MESSAGES NOTED SYS TEST NORMAL IAW MM 75 AND 36. NO FUMES NOTED EITHER. SUSPECT PACK TEMP WHEN NR 1 BUS WAS DISCONNECTED. COULD NOT DUPLICATE WITH SEVERAL ENG STARTS AND SYS CHECK OUT NORMAL IAW MM 24-20.