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Circuit opening relay


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I am rewiring my engine and building a custom loom for my MR2 with a Gen 3 3S-GTE engine and will be running it on a G4+ Fury.

While studying the existing wiring, I noted the system uses a circuit opening relay for the fuel pump where there is a second coil to switch on power to the fuel pump while the engine is cranking. As I am deleting/replacing the whole fuse box along with the relay, will it work if I just use an ordinary relay for the fuel pump? The relay will be powered by an key-on power source with the coil grounded to the ECU fuel pump output. Will the G4+ switch on the relay during cranking to provide power to the fuel pump?

Thank you!

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This guy has a good explanation of what toyota calls a circuit opening relay


Its just a normal relay that can be triggered by 2 different triggers. The wiring diagram for both 5s and 3s sw20's still shows it wired i as a normal "apply Ground from ECU to close the circuit" setup.

The link ecu's can control the fuel pump just fine with a normal single relay. I'm guessing the old toyota ecu's werent able to handle "power on only when cranking or running or for a couple seconds to prime at key on" so they used this dual trigger relay setup - factory it has 1 trigger from the clutch kill switch or park/neutral switch, and the second trigger is that FC wire from the ECU, so either of these will make the pump run. 

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