As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
10 MINUTES AFTER REACHING CRUISE ALTITUDE, AN OILY SMOKE ODOR IN THE CABIN AND DISCOVERED THAT THE CABIN WAS VERY SMOKEY. DURING DIVERSION THE SMOKE CLEARED AND CAME BACK SEVERAL TIMES BEFORE LANDING. INSPECTED ACM DUCTS FOUND NO OIL RESIDUE. RAN ENGINES WITH ECS ON AND OBSERVED NO FOUL ODORS RELATED TO OILY SMOKE. COMPILED WITH NJA ECS DUCT BURN OUT PROCEDURE.