What was found
UNUSUAL ODOR & FUMES WHEN PACKS ARE ON THE ENGINE BLEED. ODOR & FUMES ARE NON EXISTENT WHEN PACKS ARE ON THE APU BLEED. ODOR STARTED WHEN TRANSFERRING PACKS FROM APU TO THE ENGINE. ODOR DISSAPATED WHEN TRANSFERRING BLEEDS FROM ENGINES BACK TO APU BLEED. CONDITIONAL INSPECTION WAS COMPLIED WITH IAW TASK 05-51-26-800-801-C1, NO DEFECTS NOTED. PERFORMED HIGH POWER RUN WITH RECIRC FAN, BOTH BLEEDS, PACKS, APU BLEED, & WING AND ENGINE ANTI ICE, ALL CYCLED ON, NO STRANGE ODORS OR SMOKE. INSPECTED ACFT INSIDE & OUT. INSPECTED CARGO PITS, P91, FLT DECK AND NO DEFECTS NOTED.