What was found
DURING ENGINE START OF THE NR 1 ENGINE. THE ENGINE N2 ROSE VERY SLOWLY AND HUNG AT 19% AT ABOUT 40 SECONDS INTO THE START. ACFT GROUNDED. PERFORMED FIM 80-05, TASK 806, ENGINE STARTED SLOW N2 ACCELERATION TO IDLE OR HUNG START WITH NO DEFECTS NOTED. VERIFIED LT ENGINE FLOW CONTROL VALVE OPENED FULLY IAW AMM 21-51-00. CHECKED FOR LEAKS AND WING ANTI-ICE VALVE, NO LEAKS NOTED IAW AMM 30-11-11 AND AMM 30-21-00. REMOVED & REPLACED THE LEFT FLOW CONTROL VALVE IAW AMM 21-51-01. OPS AND LEAK CHECKED GOOD. REMOVED & REPLACED THE NR 1 START VALVE AMM 80-11-03. OPS TESTED GOOD. REMOVED & REPLACED AIR CONDITIONING MODULE IAW AMM 21-51-65-400-801. ACCOMPLISHED PACK ZONE TEMPERATURE CONTROLLER BITE TEST IAW AMM 21-51-00-700-803. CLEARED INDUCED FAULTS. OPS CHECKED NORMAL. INSTALLATION TESTED, CHECKED GOOD IAW AMM 21-51-65-400-801. PERFORMED FIM 36-10 TASK 806 TABLE 201, OPS NORMAL, NO DEFECTS NOTED. STARTED BOTH ENGINES 3 TIMES IAW AMM 71-00-00. BOTH ENGINES OPERATE AND STARTED NORMAL.