Toyota EFI main relay is controlled by the engine ECU. The ignition switch powers the ignition coils, injectors and IGSW pin of the engine ECU with 12v switched power. The engine ECU is grounded on the E1 pin of the ECU, constant 12v power is applied to the BATT pin of the ECU and switched 12v power is applied to the IGSW pin of the ECU. When these conditions are met the engine ECU outputs 12v on the M-RLY pin of the ECU to the 12v side of the EFI main relay coil. Then power is supplied to the EFI system, circuit opening relay for the fuel pump and feedback to the engine ECU on the +B and +B1 pins of the ECU allowing the engine to run. With this said I want to have the EMU black control the EFI main relay in this same scenario so the stock engine harness and cars wiring system operate without rewiring the whole car. Thanks in advance!
Whenever I do these I just join MREL to the ignition switch 12V.
to me its a waste of an output for the ECU to control the main relay under the exact same conditions as the ignition switch state.
Black can output 12V from the H bridges when inverted BUT since you’ve linked what I think is a JZX diagram you probably need all the H bridge outputs for idle control
If you’re using a PNP then this is already done
Thank you for your reply that is what I was expecting the solution was and I was as looking for confirmation. I’m in a different state than the car and I’m almost done building a PnP flying lead for a Japanese jzx81 that is being swapped with an Aristo 2jzgte and r154. The car is a VIP styled build and will have AC and all the interior functions of the jzx81. I’m hoping to plug the flying lead into the connectors under the dashboard terminate the wires and install the connectors that correspond to the engine, transmission and engine bay. Thanks again!
