As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT WITH ENGINE BLEEDS SELECTED ON, A BURNING OIL ODOR IN FLIGHT DECK AND CABIN. WHEN BLEEDS WERE SELECTED OFF, ODOR STARTED TO DIMISHED. GROUND RAN BOTH ENGINES AND APU FOR ABOUT 20 MINUTES. WITH BLEEDS SELECTED ON AND OFF MULTIPLE TIMES, CHANGING TEMP CONTROL SETTING. NO ODORS DETECTED. OK FOR SERVICE.