As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED HEAVY EXHAUST FUMES ENTERING CABIN THROUGH BLEED AIR SYSTEM. THIS WAS THE THIRD REPORT IN A ROW. PREVIOUS REPAIRS INCLUDED REPLACING A CRACKED EXHAUST STACK. COULD NOT DUPLICATE ON GROUND. THE FINAL DISCREPANCY REPAIRED WAS TO REPLACE NR 1 ENGINE FUEL NOZZLE SEALS. THE FINAL DISCREPANCY WAS VERIFIED ON GROUND RUNS AS WAS THE CORRECTION. (M)