GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Sunfire 🢒 Engine 🢒 Engine Electrical 🢒 Hard Start

Hard Start

Checks

Action

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

Preliminary
    • Ensure that the driver is using the correct starting procedure as described in the owner's manual.
    • Refer to Symptoms - Engine Controls .
    • Search for service bulletins.

Sensor/System
    • Inspect the engine coolant temperature (ECT) sensor for being shifted in value. Install a scan tool, and compare the ECT with the intake air temperature (IAT) on a cold engine. The ECT and the IAT should be within 3°C (5°F) of each other. Inspect 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 .
    • Ensure proper operation of the manifold absolute pressure (MAP) sensor .
    • Ensure proper operation of the throttle position (TP) sensor.
    • Ensure proper operation of the idle air control (IAC) valve.

Fuel System
    • Ensure adequate fuel level.
    • Inspect the fuel pump relay circuit for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Inspect the fuel injectors.
       - Refer to Fuel Injector Solenoid Coil Test .
    • Inspect for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect 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 into the fuel tank after the engine is stopped.
        Refer to Fuel System Diagnosis .

Ignition System
    • Ensure proper ignition voltage output with the J 26792 Spark Tester or equivalent.
    • Inspect the spark plugs for the following conditions:
       - Wet or fuel-fouled spark plugs
       - Cracks on the spark plugs
       - Wear
       - Improper spark plug gap
       - 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.
    • Inspect the ignition control module (ICM) for proper ground connection.
    • Inspect the ignition coils for cracks or carbon tracking.
    • Inspect the spark plug wires for proper resistance and condition.

Engine Mechanical
    • Inspect the engine for the following engine mechanical problems:
       - Low compression
       - A leaking cylinder head gasket
       - A worn or an incorrect camshaft
    • Refer to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical 2.2L.

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.
    • Review the scan tool data. Refer to Scan Tool Data List .