What was found
RAMP REPORTED SMOKE & FIRE SHOOTING OUT APU EXHAUST FOR A FEW SECONDS AFTER START UP. PLACED APU ON MEL. 5/1/21 PERFORMED OPS CHECK OF APU PER AMM TASK 49-00-00-710-801. OPS CHECK GOOD. STARTED 2 ADDITIONAL TIMES- NO SMOKE OR FLAMES NOTED. INTERROGATED CDS AND FOUND NUMEROUS IGNITER A AND IGNITER B OPEN FAULTS. REPLACED BOTH IGNITER PLUGS PER AMM TASKS 49-40-04-000-801 AND 49-40-04-400-801. OPS CHECK GOOD. CLEARS MEL. RETURNED TO SERVICE.