Part 1 of 2

Chart A-7 (1 of 2):

Wiring Diagram For Fuel Relay Circuit:

Fuel System Schematic:

CIRCUIT DESCRIPTION:

When the ignition switch is turned to the "ON" position, the ECM will activate the in-tank fuel pump. The fuel pump will operate as long as the engine is cranking or running, and the ECM receives an ignition reference pulse. If no ignition reference exist, the ECM will no longer supply the fuel pump a voltage signal after 2 seconds once the ignition is "ON." The fuel pump will supply fuel to the TBI unit where the pressure is controlled from 9 to 13 psi (62 to 90 kPa). When the engine is stopped, the pump can be energized by applying battery voltage to the fuel pump test terminal. See COMPONENT LOCATIONS for the proper location of the test terminal.


TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

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

DIAGNOSTIC AIDS:

1. The #5 fuse is located in the relay convenience center.
2. Improper fuel system pressure may result in one of the following symptoms:
^ Extended cranking time before the engine starts.
^ Rough idle.
^ Low idle speed.
^ Cranks, but won't run
^ Code 44 or 45
^ Cuts out
^ Poor fuel economy, loss of power, or hesitation
^ Cuts out, may feel like an ignition problem.