GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Lucerne 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Hard Start

Inspection/Test

Action

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

Sensor/System
    • Verify that the engine coolant temperature (ECT) sensor is not shifted in value. Refer to Temperature Versus Resistance .
    • Inspect the mass air flow (MAF) sensor for proper installation, obstruction, contamination, and damage. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .
    • Inspect the manifold absolute pressure (MAP) sensor for proper installation, obstruction, contamination, and damage. Refer to Manifold Absolute Pressure Sensor Replacement .
    • Inspect the MAF and MAP sensors for proper seating of the connectors and terminals.
    • Ensure the quality of the MAP sensor vacuum source.
    • Inspect for the proper operation of the exhaust gas recirculation (EGR) system. Refer to Exhaust Gas Recirculation (EGR) System Description .
    • Inspect for vacuum leaks and other unmetered air.
    • Inspect the crankshaft position (CKP) sensor for damage and proper installation. Refer to Crankshaft Position Sensor Replacement .

Fuel System
    •  Test the fuel system for correct operation, restriction, volume, and pressure. Refer to Fuel System Diagnosis .
    • Test for proper operation of the fuel injectors. Refer to Fuel Injector Diagnosis .
    • Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect the throttle body for coking. Refer to Throttle Body Inspection and Cleaning .
    • Inspect for lean or rich conditions. Refer to DTC P0171, P0172, P0174 or P0175 Conditions for Running the DTC. Refer to DTC P0171 or P0172 or DTC P0174 or P0175 .

Ignition System
    • Inspect for proper ignition system operation. Refer to Electronic Ignition (EI) System Diagnosis .
    • Inspect the spark plugs. Refer to Spark Plug Inspection .
    • Inspect the spark plugs for correct application. Refer to Ignition System Specifications .
    • Inspect for damaged ignition coils within the ignition coil module assemblies.
    • Inspect for damaged or misaligned spark plug boots.
    • Inspect the CKP sensor for damage and proper installation. Refer to Crankshaft Position Sensor Replacement .
    • Inspect the CKP sensor and harness for electromagnetic interference (EMI).

Engine Mechanical
    • Inspect the engine mechanical for oil consumption, correct engine compression, and correct base engine timing. Refer to Symptoms - Engine Mechanical .
    • Inspect for low cylinder compression. Refer to Engine Compression Test .
    • Inspect the following for incorrect or damaged basic engine parts:
       - Cylinder heads
       - Camshaft and valve train components
       - Pistons, and piston assemblies

Additional Inspections
    • Inspect the exhaust system. Refer to Symptoms - Engine Exhaust .
    • Inspect the engine electrical system for correct operation. Refer to Charging System Test .