GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Seville 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 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
    • Refer to Important Preliminary Checks Before Starting in Symptoms .
    • Search for bulletins.

Sensor/System
    • Check the engine coolant temperature (ECT) sensor for being shifted in value. Install the scan tool and compare the displayed engine coolant temperature with the intake air temperature on a cold engine. Check the resistance of the ECT sensor if the 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 MAF sensor and connections.
    • Check the operation of the IAC valve.
    • Using the scan tool, monitor the TP sensor voltage. The TP sensor voltage should be less than 0.9 volts with a closed throttle. If the TP sensor voltage is more than 0.9 volts, inspect the throttle body and accelerator cables for binding.
    • Check for the proper operation of the EGR system.

Fuel System
    • Check the operation of the fuel pump. The pump should turn ON for approximately 2 seconds when the ignition is turned ON.
    • Check for incorrect fuel pressure. Refer to Fuel System Pressure Test .
    • Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System
    • Check the operation of crankshaft position sensors A and B. Refer to DTC P1372 Crankshaft Position (CKP) Sensor A-B Correlation .
    • Check for proper ignition voltage output using the spark tester J 26792.
    • Check for damaged ignition coils within the ignition coil module assemblies.
    • Check for damaged or misaligned spark plug boots.
    • Check for a missing or damaged ignition module ground spring.

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

    • Check the spark plugs for the following conditions:
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Wrong heat range or improper reach
       - Burned or damaged electrodes
       - Excessive deposits

Engine Mechanical
    • Excessive oil in combustion chamber-leaking valve seals. Refer to Oil Leak Diagnosis in Engine Mechanical.
    • Check for low cylinder compression. Refer to Engine Compression Test in Engine Mechanical
    • Check for incorrect or damaged basic engine parts. Inspect the following:
       - Cylinder heads
       - Camshaft and valve train components
       - Pistons, and piston assemblies