As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER STARTUP & WARM UP ON GND, FUEL LEVER MOVED FROM GROUND IDLE TO FLY POSITION. MGB CHIP LIGHT ILLUMINATED, PILOT BEGAN ENG SHUTDOWN. GRINDING NOISE HEARD COMING FROM MGB DURING SHUTDOWN. SUBSEQUENT INSPECTION BY MECHANIC FOUND HEAVY CONTAMINATION OF LOWER CHIP DETECTOR & FILTER CARTRIDGE WITH METAL PARTICLES.