The zr engine was 1.4 ear 2002

Hello y have this rover 200 vi and y want to change this motor to an mg zr y have all the pieces ecu imobilazor keys and front engine wires, y change the engine and the ecu recognise the imobelizor but when y turn on the staryer engine theres no power in the spark plugs... can any ine give a pick? A...