1 of the black wires that is for the immobiliser is fitted wrong, the alarm is not seeing that you are staring the car. it works by 1 wire on the immob circuit is an input the other an output ,and they are specific as to where they need to be connected eg ign switch, fuel pump, starter etc, they only work a certain way. you cant just leave them disconnected either as 1 of the inputs energises the whole immob circuit. you need the clifford diagram and to take the silver box apart. alternatively its a long case of trial & error.