What was found
ON T/O FROM EWR NOTICED A SMALL SPLIT IN N1 ON CLIMBOUT ACARS MESSAGE ON PRINTER NOTIFYING US THAT LEFT PACK WAS OFF. LEAD US TO BELIEVE WE HAD A PACK PROBLEM WHEN WE IN FACT HAD A NR 1 ENG. BLEED TRIP ON T/O WITH NO INDICATION/ MASTER CAUTION OR WARNING. INSPECTED NR 1 ENGINE CORE FOR LOOSE SENSE LINES AND VALVE INSTALLATION. JUMPED OUT 490 DEGREE SENSOR - OPERATED PACK TRIP LIGHT VERIFIED GOOD. PERFORMED ENGINE RUN-UP HIGH POWER - BLEED VALVES, PACKS, ISO VALVE OPERATIONS ALL NORMAL. COULD NOT DUPLICATE BLEED TRIP NO IND. BLEED VLVS, PACKS NR 1/2 ALL NORMAL.