What was found
UPON ENGINE START BURNT OIL SMELL AND HAZE / FOG / SMOKE REPORTED IN CABIN BY CUSTOMERS AND FLIGHT ATTENDANTS. REMOVED AND INSTALLED APU. TORQUED MOUNT BOLTS ONLY. NOTE FIREWALL INSPECTION COMPLIED WITH, APU INSTALLATION COMPLETED PER AMM 49-13-02. LEAK AND OPS CHECKS OK. RAN BOTH ENGINES AND APU WITH PACKS ON, NO DISCREPANCIES NOTED. ROTABLE PARTS CHANGE WAS INDICATED - TT 1336219, S/N OFF 02835 APU, AUX POWER UNIT OFF 19-4911-9-0002 2835 ON 19-4911-9-0002, S/N ON 2355.