As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT WITH 2 ENGS RUNNING AND APU OFF PREVIOUS SMELL IS STRONG AGAIN IN CABIN. BURNING PLASTIC ODOR WITH SMOKE 10 MINS AFTER PACKS ON. NO PNEUMATICS DUE TO ODOR IN CABIN WITH APU RUNNING. REF TSM & THE INLET AREAS FOR UNWANTED MATERIALS. ACCOMPLISHED TSM 49-00-00 -810-921. FOUND LEAKING OIL HOSE FWD OF INLET. REPLACED HOSE. ALSO BROKEN CHECK VALVE AT SCROLL. REPLACED RECIRC FILTERS. RAN PACKS FULL HOT WITH THE APU BLEED, DID NOT NOTICE ANY EXTRA ODOR IN THE CABIN. NO RESIDUAL ODOR AFTER APU REPLACED.