What was found
#1 ENGINE "A" OVHT LOOP WILL NOT PASS PREFLIGHT TEST. GROUNDED - YES. C/W ENG FIRE DETECTION OPERATIONAL TEST - ENG #1 A / B LOOPS TEST NORMAL. OPENED ENG #1 FAN COWLS AND THRUST REVERSERS. ACCOMPLISH VISUAL AND PHYSICAL INSPECTION OF ENG #1 LOOPS AND LUG CONNECTIONS WITH NO DEFECTS NOTED. PHYSICALLY TAPPED ALL LOOP A DETECTORS LOOKING FOR A TEST FAILURE, NO FAULTS NOTED. PHYSICALLY TAPPED CONNECTOR DJ2501 AND ENG #1 LOOP A FAILED TEST. TAPPED DJ2501 AGAIN AND FAULT WENT AWAY/COULD NOT BE DUPLICATED. REMOVED ENGINE AND APU FIRE DETECTION MODULE AND C/W ENG FIRE DETECTION LOOP RESISTANCE TEST WITH NO DEFECTS NOTED. REINSTALLED FIRE DETECTION MODULE.