As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
COCKPIT ODOR: WHEN STARTING ENGINES WITH APU RUNNING, HEAVY SMELL OF JET EXHAUST IN CABIN AND COCKPIT. APU BLEED WAS SELECTED OFF 2+ MINUTES PRIOR TO ENGINE START. CORRECTIVE ACTION: REPLACED HEPA FILTER IAW CE-680A AMM 21-70-10 OPS CHECK GOOD