What was found
AFTER 2ND ENG START, BURNING PLASTIC ODOR IN BACK WITH VISIBLE SMOKE IN AFT GALLEY. PILOT STATED THE PLASTIC ODOR RETURNED AFTER ENG 2 WAS STARTED & APU DESELECTED, ENG 1 ON. ACCOMPLISHED ENGINE RUN. ATTEMPTED TO REPLICATE FLT CREW ENGINE START PROCEEDURE AS INDICATED TO DUPLICATE SYMPTOMS. NOTHING OUT OF THE ORDINARY NOTED. NO SMOKE, NO HAZE OR STRONG ODOR. NO ECAM MSG OR FAULTS NOTED. COMPLETED WALK AROUND & INSPECTED FAN BLADES & COMPRESSOR INLET GUIDE VANES ON BOTH ENGS, NO OBVIOUS FOD DAMAGE OR INJESTION INTO ENGINES. NR 2 ENGINE T/R NEEDS TO BE OPENED & INSPECTED FOR RAGS, OIL LEAKS OR ANY OBVIOUS DEFECT ON THE EXTERNAL OF ENGINE. INSPECTED ENG 2, NO RAGS, OR FOD WITHIN FAN & THRUST REVERSER COWLS, NO OBVIOUS LEAKS OR DEFECTS. UNABLE TO DUPLICATE FAULT ON THE GROUND.