I did the something similar in my early 260Z.
If you look at the wiring diagram, the jumper bypasses the cut relays and runs the pump all the time with key ON. This also takes out all fuel-pump shutoff devices in case the car is in an accident, thus the pump will keep pumping fuel even with the engine dead, the car upside-down, etc.
As you will find in the FSM, cut relay #1 deactivates the pump if engine speed goes below 400rpm and cut relay #2 kill the pump during cranking.