1994 Nissan Truck Idiot Move on my behalf.

Was pouring down rain when I got in my vehicle. Truck wouldnt start (old battery) so I rolled it down the driveway and popped it in gear, it started. I was thinking when I get to point B, I wouldnt have any help to start. So my thoughts were to change out the battery. I pulled it into the garage and kept the vehicle running. I disconnected the positive, negative cables, pulled out the bad battery and proceeded to install a much larger battery. This is when the positive cable came in contact with metal and the truck immediately died. When I put in the freshly charged battery I tried to start but it didnt start. Okay so I checked all the fuses, all okay. I disconnected the outlet gas line from the fuel filter and turned the ignition. Gas shot out pretty far so I know the fuel pump works. I took off air cleaner and poured gas into carb, it ran for a bit. So I think its an electrical problem that tells the injectors to open/close. (Since gas is going to the injectors). Must it be a relay or something telling the injectors to open? Thanks for your help