What was found
BAD ODOR FROM ENVIROMENTAL SYS WITH ENGS RUNNING. CHECKED BLEED AIR SYS, APPLIED HEAT TO MAX, INSPECTED THE APU INLET DUCTS, INSPECTED THE APU CARBON SEAL, PERFORMED A VACUUM CHECK OF APU GB VENT, AND RAN APU FOR ONE HOUR PERFORMING CHECKS, NOT ODOR DETECTED.