first off, on a efi vehicle, pushing the "gas" pedal goes nothing but operate the throttle blade. ecu controls fuel delivery via injector pulses while it's running.

to answer your question though, you are on the right track with taking the line off and turning the key on. but it will only cycle the pump for a few seconds. what you can do, is locate your fuel pump relay and jumper it across the power and output contacts to continuously run the pump. if you have any questions about jumpering the relay, don't guess at it. look up a schematic on the relay pin configuration and do it accordingly. you don't want to be replacing an ecu or harness trying to get gas out of it