What was found
FOUL ODOR OF FUMES/OIL COMING FROM PACKS WHILE ON BOTH ENG & APU BLEED. ACCOMPLISHED LEVEL A DECONTAMINATION OF ECS WITH APU BLEED IAW AMM 21-00-00-615-802-A. ODOR OF OIL/FUMES PERSISTS. ACCOMPLISHED DECONTAMINATION OF ECS WITH ENGINES 1 & 2. SMELL FADED WITH ENG BLEED BUT ODOR CAME BACK AFTER SWITCHING TO APU BLEED. ACCOMPLISHED INSPECT OF APU UPON ODOR/FUMES IN CABIN LEVEL B/C. FOUND APU INLET PLENUM DIRTY WITH SIGNS OF OIL RESIDUE. FOUND MINIMAL OIL IN BETWEEN MID & AFT DRAIN VENTS. INSPECTED LOAD COMPRESSOR BUFFER PRESSURE TUBE ASSEMBLY, THE HOUSING PORTS & TEE-FITTING FOR BLOCKAGE. NO BLOCKAGE FOUND. CANNOT IDENTIFY EXTERNAL OIL LEAKAGE. TROUBLESHOOTING DOES NOT HELP. REF AMM 49-00-00-200-816-A REMOVED APU IAW AMM 49-11-11-000-003-A. FIREWALL INSPECTION & APU DUCT INSPECTION. ACCOMPLISHED FIRE WALL INSPECTION, NO DEFECTS, MOUNTED APU TORQUED 3 MOUNT BOLTS, INSTALLED GENERATOR TERMINAL LEADS & TORQUED, CONNECTED ALL ELECTRICAL CONNECTORS & ATTACHED FUEL SUPPLY LINE. PNEUMATIC SUPPLY V-BAND INSTALLED & TORQUED IAW 49-11-98-890-001-C1. NO CABIN ODOR NOTED.