What was found
DURING TAXI AFTER LANDING, THE AIRPLANE FILLED WITH SMOKE THAT SMELLED LIKE BURNED RUBBER. THE PAC WERE TURNED OFF INDIVIDUALLY AND THE CABIN PAC (RT) WAS BLOWING VERY HOT AIR. THE AIRPLANE PRESSURIZED AT A SLOWER THAN NORMAL RATE ON DESCENT. HEARD A LOUD (SLAM SOUND) COMING FROM BACK OF THE CABIN AREA. R & R FWD ECU DIR CYCLE MACHINE WITH A REPAIRED UNIT; R & R FWD AFT WATER SEPARATORS COALESCING AS REQUIRED. PERFORMED OPS TEST, CHECKED SATISFACTORY IAW MM 21-11-00.