I run a collision and restoration business and am currently face-lifting a 92 miata. While prepping under the hood for a color change while several wiring connectors were disconnected an attempt to start the vehicle was made. It wouldn't start and after reconnecting all wires it still wont start. With a shot of ether it did try ie got fire. The fuel pump relay seems to work ok and by jumping the front two terminals together by the advise of a mazda tech on the phone the pump still didn't run. Removed pump and checked it on bench and it runs but it won't come on when attached to the harness, there is a hot wire at the pump suspiscion is there is no ground. Any suggestions????

 

The ground for the in tank pump is located in a junction block near the rear license plate in the trunk. The power comes right from the relay.

There are 5 wires on the relay:
blu/red - to the pump
light green - to the mass air flow meter to get a ground
wht/red - 12V from the main relay
violet - PCM
black - ground