Like Blwn31 said, not having a wiring diagram makes it hard to diagnose but on my aftermarket system the fuel pump gets it's signal from the ECU (through a relay) and it did the same thing once - running fine until I plugged in a hand held calibrator. It blew the in-line fuse to the ECU, dropping power to my coil, injectors and fuel pump. A new 3A fuse feeding the relay to the ECU brought it all back to life. I now carry a bag of fuses.