System Description

BASIC OPERATION STRATEGY
When the ignition switch is turned to the START position, current flows, by way of the Multiport Fuel Injection (MFI) relay coil, from the ignition switch to ground. As a result, the MFI relay switch is switched on, and the power for activation of the fuel pump is supplied, by way of the MFI relay switch, from the battery to the fuel pump.
While the engine is running, the engine control module switches ON the power transistor, after which current flows to the MFI relay coil, and the power for activation of the fuel pump is supplied to the fuel pump

TROUBLESHOOTING HINTS
Listen for the operation of the pump during the first few seconds after the ignition key has been placed in the "ON" position. If you have trouble hearing the pump, take off the gas cap and put your ear to the filler neck while an assistant cycles the key.