As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU WOULD HANG AT 250-300 DEGREES FOR APPROXIMATELY 30 SECONDS DURING START AND THEN ACCELERATE. APU WAS MAKING CHUGGING EXHAUST NOISES WHEN RUNNING. SB GTCP85-49-7484 INCORPORATES A NEW FUEL CONTROL AND ATOMIZER/ LINER ASSEMBLY, PN 3604524-54 TO IMPROVE START TIMES. REPLACED FUEL CONTROL AND ATOMIZER/LINER ASSEMBLY IAW THE SB AND AMM. APU STARTS MUCH QUICKER NOW AND NO LONGER MAKES CHUGGING NOISES WHEN OPERATING.