What was found
(CAN) AT 10,000 FT TRIED TO START THE APU, NO LIGHT OFF. APU SELECTED OFF. 2 MINUTES LATER, ATTEMPTED ANOTHER START, START COMPLETED, FUEL TRANSFERRED WITH STRONG SMELL OF FUEL, EGT HIGHER THAN NORMAL WITH ONE FIRE DETECTOR LOOP INOP. APU SHUTDOWN AND FIRE BOTTLE DISCHARGED. APU FIRE EXTINGUISHER BOTTLE AND SQUIB REPLACED. FIRE DETECTION LOOP REPLACED. SYSTEM TESTED SERVICEABLE. APU AND ENGINES RUN FOR 3 MINUTES, NO SMELL OF FUEL, ALL SYSTEMS OPERATE NORMAL. AIRCRAFT SERVICEABLE.