As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN STARTING APU, THERE IS A MILDLY NOXIOUS ODOR THAT FILLS THE COCKPIT AND CABIN. IT SMELLS LIKE BURNING OIL. ODOR REMAINS FOR THE ENTIRE FLIGHT, EVEN WITH APU OFF. SUSPECT COMING FROM THE APU AND RESIDUAL FUMES ARE LINGERING FOR REMAINDER OF FLIGHT, BUT NOT SURE. REMOVED APU AND INSTALLED CUSTOMER SUPPLIED INSPECTED APU. COMPLIED WITH OPS CHECKS AND LEAK CHECKS OF APU WITH POWER ON RUNS. IAW AMM 49-10-00.