What was found
DURING ENGINE START, THE CREW OBSERVED AND SMELLED SMOKE IN THE COCKPIT. THE CREW REPORTED TO MAINTENANCE THAT THE SMOKE HAD AN OILY ODOR. MAINTENACE REMOVED ALL ENGINE DRIVEN COMPRESSOR (EDC) DUCTING AND INSPECTED FOR OIL, NONE WAS FOUND. THE EDC OIL LEVEL WAS CHECKED AND WAS NORMAL. MAINTENANCE RAN THE ENGINE AND OPERATED THE AIR CONDITIONING SYSTEM HOT AND COLD A NUMBER OF TIMES. NO SMOKE WAS NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.