What was found
APU HAD A SLIGHT FUEL ODOR WHEN FUNNING PACKS WITH APU AS AIR SOURCE. REQUESTING MEL 4901A. OK TO PLACE APU ON MEL 4901A. CURRENTLY UNABLE TO LOCATE SOURCE ON APU. APU ON MEL FOR SLIGHT FUEL ODOR ON PACK START UP WITH APU AS SOURCE, INSPECTED APU AND BOTH PACKS WITH NO DEFECTS NOTED, UPON CLEARING MEL, PERFORMED T/S IAW TSM 49-55 TASK 802, NO FAULTS FOUND AT THIS TIME. RAN LT & RT PACKS ON FULL HOT FOR ONE HOUR IAW AMM 05-51-26-800-801-C1 STEP (E). NO FUMES NOTED. REPLACED LT & RT RECIRC FILTERS AS PRECAUTION.