my fuel pump wasn't getting power. is there a relay for that on these trucks and 4runners? when I probed the wire while my buddy cranked the engine over the pump started working. now I'm confused. did the instant I probe the wire reset the relay and make the pump start working again?

 

Which wire did you probe?

There are 2 relays between power and the fuel pump. The first is the EFI main relay, which powers the fuel injection components (fuel pump, fuel pressure regulator, O2 sensor, etc.). The second is the Circuit Opening Relay, which provides power to the fuel pump. The EFI relay powers the circuit opening relay. The circuit opening relay can be checked by measuring the voltage at the FP pin of the check connector. If you have voltage there, then the relays are working.

Edit: If you have voltage across +B and E1, the EFI main relay is functioning. If you have voltage across FP and E1, the circuit opening relay is functioning. There is also a switch located in the air flow meter, which needs to be on for the fuel pump to run as well. If you jumper +B and FP, the fuel pump should run. The fuses that control the fuel pump are the IGN, and the EFI.

 

thank you

 

the COR is a dual-coil relay. It has 5 terminals: ground, + from ignition (when cranking), + from afm (with key in 'run' and sufficient airflow through afm), + (from efi relay), + to fuel pump.
the COR only gets actuated (turned on- B+ connected to fuel pump) when the ignition switch is in the 'start' position (as in cranking the engine to start) or when the airflow through the air-flow meter is high enough to close the contacts in the afm.

likely, the wire's connection was loose or corroded, and wiggling it while probing caused it to make better connection.