GM Service Manual Online
For 1990-2009 cars only

Checks

Action

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

Preliminary

    • Check PCM grounds for being clean, tight and in their proper locations.
    • Search for bulletins.

Sensor/System

    • Check Engine Coolant Temperature (ECT) sensor for being shifted in value. Connect a Scan Tool and compare Engine Coolant Temperature with Intake Air Temperature on a cold engine. The ECT and IAT should be within ± 3°C (5°F) of each other. Check the resistance of the ECT sensor if the temperature is out of range with the IAT sensor. Refer to Temperature vs Resistance for resistance specifications. Replace the ECT sensor if the resistance is not within the specification. Refer to Engine Coolant Temperature Sensor Replacement . If the sensor is within the specification, repair ECT signal circuit for high resistance.
    • Check Mass Air Flow sensor installation.
    • Using a Scan Tool, monitor TP sensor voltage. The TP sensor voltage should be less then 0.9 volts at rest. If the TP sensor voltage is greater than 0.9 volt, inspect the throttle body and accelerator cables for binding.
    • Check the EGR system for proper operation.

Fuel System

    • Check fuel pump relay operation -- pump should turn ON for 2 seconds when ignition is turned ON.
    • A faulty in-tank fuel pump check valve will allow the fuel in the lines to drain back to the tank after engine is stopped. To check for this condition, refer to Fuel System Pressure Test .
    • Check both injector fuses for being open. An open injector fuse will cause four injectors not to operate. Replace fuse and inspect injector circuits for an intermittent short to ground.
    • Check for low fuel pressure.
    • Check for restricted fuel filter.
    • Check for contaminated fuel. Refer to Fuel Quality Diagnosis .

Ignition System

    • Check for proper ignition voltage output with spark tester J 26792.
    • Remove spark plugs and check for the following:
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits

If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

    • Check for bare or shorted ignition wires. Refer to Secondary Ignition Diagnosis .
    • Check for loose Ignition Control module ground.
    • Spark plugs for proper heat range.

Engine Mechanical

    • Excessive oil in combustion chamber or leaking valve seals.
    • Low cylinder compression.
    • Combustion chambers for excessive carbon buildup. Clean using Top engine cleaner. Follow instructions on container.
    • For incorrect basic engine parts. Inspect the following:
       - Cylinder heads
       - Camshaft
       - Pistons, etc.

Additional Checks

Using a scan tool, check IAC operation and Typical Scan Data values.