GM Service Manual Online
For 1990-2009 cars only

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DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

Preliminary

    • Refer to the Symptoms .
    • Search for bulletins.

Sensor/System

    • Test engine coolant tamperature (ECT) sensor for being shifted in value. Install a scan tool and compare the displayed engine coolant tamperature with intake air temperature on a cold engine. Test the resistance of the ECT sensor if engine coolant temperature is not within ± 3°C (5°F) of intake air temperature. Refer to Temperature Versus Resistance . If the ECT sensor resistance is not within the specification, refer to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage or DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage .
    • Inspect the throttle body inlet screen for foreign objects or damage that may affect the MAF sensor airflow sample. Refer to Throttle Body Air Inlet Screen Replacement .
    • EGR system. Inspect for the following conditions:
       - EGR pipes and adapter for vacuum leaks.
       - Remove the EGR valve and inspect for a stuck open pintle. Refer to Exhaust Gas Recirculation Valve Replacement .

Fuel System

    • Test the fuel pump relay circuit for proper operation.
    • Test for incorrect fuel pressure.
    • Refer to Fuel System Pressure Test
    • Test the fuel injectors.
    • Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System

    • Test for proper ignition voltage output using the following steps:
       - Clip the J 26792 spark tester to engine ground.
       - Connect one end of a spark plug wire to the spark tester, leave the other end of the spark plug wire to the coil being tested.
       - Connect one end of another spark plug wire to the other coil tower, connect the other end of the spark plug wire to ground.
       - Crank the engine while observing the spark tester, a spark should be observed.
       - Repeat the above steps for each coil.
    • If adequate spark is not present at the coils, inspect for the following conditions:
       - Coils - Cracks, carbon tracking/arcing, or a resistance value outside the specified range.

Coil Secondary Resistance
5000 - 8000 ohms (5K - 8K ohms)

       - Spark Plug wires - Signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, incorrect routing, or a resistance value more than the specified value.

Spark Plug Wire Resistance
3280-4921 ohms/meter(1000-1500 ohms/ft)

   Important: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition components will arc to ground when a secondary component is malfunctioning.

       - Malfunctioning ignition control module.
       - Ignition System Wiring - Loose ignition module feed or ground connection, or damaged system wiring.
    • Remove spark plugs and inspect for the following conditions:
       - Fouled plugs
       - Cracks
       - Wear
       - Incorrect gap
       - Burned or damaged electrodes
       - Incorrect heat range
    • If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Engine Mechanical

    • Excessive oil in combustion chamber-Leaking valve seals.
    • Low cylinder compression.
    • For incorrect basic engine parts. Inspect the following:
       - Cylinder heads
       - Camshaft and valve train components
       - Pistons, etc.
       - Refer to Base Engine Misfire Diagnosis in Engine Mechanical.