Iveco 75E17 engine won't start ? ?

Hi, I have an Iveco 75E17 2001 model, I blew my ECU after I had wrongly connected the batteries. I replaced the ECU and the injectors after the diagnostics machines had reported for those two errors. The problem is that the truck can't start. I bought new batteries and the injectors are making the ticking sound. Wht could b the problem. The ECU was by-passed.