What was found
AIR TURNBACK. AFTER ROTATION, OVERPOWERING ODOR FROM PACKS FILLED COCKPIT, RETURNED TO BASE. PERFORMED FIM TASK 21-20-00-810-801A FOR ABNORMAL ODOR AFTER AN ENGINE COMPRESSOR WASH ON NR 1 ENGINE, RAN NR 1 ENG FOR 15 MIN. NO ABNORMAL ODOR NOTED. OK FOR SERVICE.