1993 Toyota Camry xv10 2.2l auto
The vehicle had driven to the workshop with a battery feed to the fuel pump.
The testing had begun with the back seat out of the vehicle and the fuel pump cover removed.
A voltmeter was used to test the fuel pump 12v feed and it concluded that 5 volts was present, ( not enought to run a fuel pump).
A voltmeter was used to check the earth circuit and the earth was in good health.
So when the connection is put back on to the fuel pump the vehicle would stall.
It was then up to looking at a wiring diagram to trace the power circuit back to it source of power supply and test the fuel pump wiring back to the source.
The wiring diagram below (fig.1) show that the power to the fuel pump. Is supply by the circuit opening relay (located behind glove box) and the circuit opening relay is supplied by the EFI relay. The circuit opening relay supplies power to the fuel pump, VSV Valve, idle speed control valve and supplies power to the ECU.
The power loss was found under the glove box with a wiggle test careful analysis proved that terminals in a wiring harness plug were faulty (fig.2 ) shows the harness and the terminals cut out of the harness and manually joined. The vehicle was then once again wiggle tested vigorously over the next day.