You will need to trace the harness to find the junction point of the 4 injectors into 1 and inspect the solder joint of the green/red wires that supply +12 vdc to the injectors, then check the continuity from injector 1 to that joint to determine if the wire is broken or the solder joint is cracked.
Probably need to check for the yellow/gray control wire 4-into-1 joint also. If the injector#1 harness got pinched it might break both wires.