95 4.3L starting issues

I have a 95 4.3L vortec (W) in an 87 toyota pickup. I welded a mounting plate on the frame rail for an inline fuel pump. After I had everything put back together, the vehicle wouldnt start up. Before welding I forgot to disconnect the neg. battery cable. Im wondering if i shorted out the ECU from welding. I know the pump works, because it was installed already. The plugs have spark. It turns over strong. I can hear the pump turn on. Also, I put some gas into the intake and that wouldnt even fire.