As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STARTING THE NR 1 ENGINE, ISOLATION VALVE CLOSED POSITION NOTICED A SLOW RISE IN ACCELERATION. SMELLED BLEED THROUGH AFTER START WITH DUCT PRESSURE EQUAL. RECONFIGURED AND ISOLATION VALVE, WORKED NORMALLY. ACFT GROUNDED. FOUND THE ISOLATION SWITCH ON THE AIR CONDITIONING MODULE TO BE BAD. CHANGED THE AIR CONDITIONING MODULE IAW AMM 21-51-65-400-801, ALL OPS CHECKED GOOD AND ENGINE START WAS GOOD.