Chart A7 (1 Of 2) - Fuel System Diagnosis: Notes

When the ignition switch is on, the ECM will turn on the in-tank fuel pump. It will remain on as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

If there are no reference pulses, the ECM will shut off the fuel pump within 2 seconds after the key is turned on. The pump will deliver fuel to the TBI unit, where the system pressure is controlled to 9-13 psi (6.2-9.0 kg/cm² ). Excess fuel is then returned to the fuel tank. The fuel pump test terminal is located in the left side of the engine compartment. When the engine is stopped, the pump can be turned on by applying battery voltage to the test terminal.

1. Fuel pressure should be noted while fuel pump is running. Fuel pressure will drop immediately after fuel pump stops running due to a controlled bleed in the fuel system.