94 blazer ecm/ign short
 

I have a 94 blazer with a transplanted 04 chevy 350 motor. It keeps blowing the ecm/ign fuse I can shake the wires and it will stop blowing the fuse. I would shake the fuel pump wires and it will refire, changed fuel pump and pulled all wires up to the firewall. Ran for a day or so and blew it again. Shaking the wires and tracing the wires from underneath problem looks behind motor. Chilton does not cover blazer wiring, nor does Hanes. what is feed ffrom this ecm/ign fuse( 10 amp).