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

Chart A-5:

Crank Signal Circuit:

CIRCUIT TEST DESCRIPTION:

When the engine is cranked the ECM will turn "ON" the circuit opening relay to operate the fuel pump. Once the engine has started, the starter signal is removed from the circuit opening relay and the fuel control switch in the MAF sensor continues to run the fuel pump. If the fuel control switch in the MAF sensor is non-functional, the engine will start but will not stay running.

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

1. Fuel pump should run when ignition is cranked.

2. Test for B+ from circuit opening relay to fuel pump.

3. Checks for B+ signal to circuit opening relay.

4. Checks for proper MAF fuel pump switch.

DIAGNOSTIC AIDS:

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