What was found
ODOR IN THE CABIN, FROM ENGINE START TO TOP OF DESCENT. MORE NOTICEABLE IN AFT CABIN. ACFT GROUNDED. IAW TSM 05-50-00-810-831-A RAN THE NR 1 ENGINE, ODOR PRESENT ON THE NR 2 ENGINE. IAW TSM 71-00-00-810-802-A COMPLETED TROUBLESHOOTING. FOUND NO ODOR COMING FROM THE NR 1 OR 2 ENGINES DURING RUN AND TAXI. PERFORMED IDLE RAN ON ENGINE 1 & 2 ONE AT A TIME IAW AMM 71-00-00, AND OPERATED PACKS AND OBSERVED THE ODOR IN COCKPIT AND ENTIRE CABIN. NO BAD ODOR.