Chart A-5 Engine Cranks But Won't Start (Fuel System)

Engine Cranks But Won't Run:

Chart A-5 Wiring Diagram:

CIRCUIT DESCRIPTION:

When the ignition switch is turned "ON" the ECM will turn "ON" the fuel pump relay to operate the pump for 2 seconds. If the ECM receives ignition reference pulses the fuel pump will continue to run. If the ECM receives no reference pulses from the ignition circuit it will shut "OFF" the fuel pump.

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

1. Fuel pump should run for approximately 2 seconds when ignition is "ON."

2. Test for an open between fuse and relay.

3. Check for open or the ECM fuel pump driver being faulty.

4. Jumpering relay connect to fuel pump. Power lead will test the fuel pump and the lead wire.

5. This will determine if ECM fuel pump circuit inside the ECM is faulty.

DIAGNOSTIC AIDS:

Visual inspection of wiring and connectors should be made if an intermittent problem exists.