Circuit Description

When ignition switch is turned on, 9-14 volts is applied to terminal IGSW at ECM. EFI relay control circuit in ECM then sends a signal to terminal MREL at ECM to switch EFI relay on. This signal causes current to flow to coil, closing contacts of EFI relay and supplying power to terminal +B of ECM. If ignition switch is turned off, ECM continues to switch on EFI relay for a maximum of 2 seconds for initial setting of throttle valve.