Engine Cranks, But Will Not Run

Diagnostic Chart:

Wiring Diagram:

Circuit Description

This table assumes that the battery condition and engine cranking speed are OK, and there is adequate fuel in the tank.

Diagnostic Aids

If no trouble is found in the fuel pump circuit or the ignition system and the cause of an Engine Cranks But Will Not Run has not been found, check for the following conditions:

^ Fouled spark plugs.

^ An EGR valve stuck open.

^ Low fuel pressure. Refer to Fuel System Pressure Test.

^ Water or foreign material in the fuel system.

^ A grounded Ignition Control (IC) signal circuit may cause a No Start or a Start then Stall condition.

^ Basic engine problem.

The VCM has integrated IC circuits that are fault protected; therefore, if a circuit has failed, the failure may not damage the integrated IC. If that is the case, the IC will keep the circuit open until the fault in the circuit has been corrected.

When the fault has been corrected, reinstall the VCM. Check the circuit. Replace the VCM only if the circuit is still inoperative.


Test Description

The numbers below refer to the step numbers on the diagnostic tables.

2. If the signal is over 2.5 volts, the engine may be in the clear flood mode which will cause starting problems.

3. If the engine coolant sensor is below -30°C, the VCM provides fuel for this extremely cold temperature which will severely flood the engine.

5. This step checks the Ignition feed to the fuel injector.

6. Voltage at the spark plug is checked using the spark plug tester tool J 28792. No spark indicates a basic ignition problem.

7. This test will determines it there is fuel pressure at the fuel injection unit and holding steady.