GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Sunfire 🢒 Engine 🢒 Engine Electrical 🢒 Hard Start

Hard Start

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 to see if the driver is using the correct starting procedure as described in the owners manual.
    • Refer to Symptoms - Engine Controls .
    • Search for service bulletins.

Sensor/System
    • Check the engine coolant temperature (ECT) sensor for being shifted in value.
    • Install a scan tool and compare the engine coolant temperature with the intake air temperature on a cold engine. The ECT and intake air temperature (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 Versus Resistance . If the ECT sensor resistance is not within the specification, refer to DTC P0117 or DTC P0118 .
    • Check for proper operation of the manifold absolute pressure (MAP) sensor .
    • Check for proper operation of the throttle position (TP) sensor.
    • Check for proper operation of the intake air control (IAC) valve.

Fuel System
    • Check for adequate fuel level.
    • Check the fuel pump relay circuit for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Check for incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injectors.
       - Refer to Fuel Injector Solenoid Coil Test .
    • Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Check the in-tank fuel pump check valve. The in-tank fuel pump check valve may be malfunctioning, causing the fuel in the lines to drain back to the fuel tank after the engine is stopped. Refer to Fuel System Diagnosis .

Ignition System
    • Check for proper ignition voltage output with the J 36012-A Spark Plug Jumper Wires and J 26792 Spark Tester or equivalent.
    • Check the spark plugs for the following conditions:
       - Check for wet or fuel fouled spark plugs.
       - Check for cracks on the spark plugs.
       - Check for wear.
       - Check for improper spark plug gap.
       - Check for burned electrodes or heavy deposits.
    • If the spark plugs are fuel or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
    • Check the ignition control module (ICM) for proper ground connection.
    • Check the ignition coils for cracks or carbon tracking.

Engine Mechanical

Check the engine for the following engine mechanical problems:

    • Check for low compression. Refer to Engine Compression Test in Engine Mechanical 2.4L.
    • Check for leaking cylinder head gasket. Refer to Engine Compression Test in Engine Mechanical 2.4L.
    • Check for a worn or a incorrect camshaft. Refer to Symptoms - Engine Mechanical in Engine Mechanical 2.4L.

Additional Checks

If all procedures have been completed and no malfunctions have been found, review and inspect the following items:

    • Visually and physically inspect all electrical connections within the suspected circuit and/or systems.
    • Check scan tool data. Refer to Scan Tool Data List .