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

Chart A-5:

CIRCUIT TEST DESCRIPTION:

When the engine is cranked the ECM will turn "ON" the circuit opening relay to operate the fuel pump. 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 when ignition is cranked.

2. Test for an open between fuel pump and ground circuit opening relay.

3. Checks for crank signal to circuit opening relay.

4. Checks for proper EFI relay operation.

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

DIAGNOSTIC AIDS:

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