GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Terraza Ext. 🢒 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.

Preliminary
    • Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls .
    • Inspect the powertrain control module (PCM) grounds for being clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics .
    • Search for bulletins.
    • Verify that the driver is using the correct starting procedure as described in the owners manual.

Sensor/System
    • Inspect for an engine coolant temperature (ECT) sensor that has shifted in value . Refer to Temperature Versus Resistance .
    • Inspect the mass air flow (MAF) sensor for proper installation. Refer to Mass Airflow Sensor Replacement . A damaged MAF sensor may cause a hard start.
    • Inspect the camshaft position (CMP) sensor for proper mounting and/or a bad connection. An extended crank occurs if the PCM does not receive a CMP signal.
    • Verify proper operation of the manifold absolute pressure (MAP) sensor. Refer to Manifold Absolute Pressure Sensor Diagnosis .
    • Inspect the exhaust gas recirculation (EGR) system for proper sealing/connections and operation. Refer to Exhaust Gas Recirculation (EGR) System Description .

Fuel System
    • Verify there is adequate fuel.
    • Inspect the fuel pump operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Inspect for a restricted fuel system. Refer to Fuel System Diagnosis .
    • Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System
    • Inspect for proper ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis .
    • Remove the spark plugs and inspect for the following conditions:
       - Correct heat range
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits
       - Refer to Spark Plug Inspection .
    • Determine the cause of the conditions before replacing the spark plugs.
    • Inspect for bare or shorted ignition wires. Refer to Spark Plug Wire Inspection .
    • Inspect for loose ignition coil grounds.
    • Inspect the ignition control module (ICM) for proper ground connection.
    • Inspect the ignition coils for cracks or carbon tracking.
    • Soak the secondary ignition wires with water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.

Engine Mechanical

Inspect for the following conditions:

    • Excessive oil in combustion chamber or leaking valve seals--Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • Cylinder compression--Refer to Engine Compression Test in Engine Mechanical.
    • Improper valve timing
    • Combustion chambers for excessive carbon buildup--Clean the chambers using top engine cleaner. Follow the instructions on the can.
    • Incorrect basic engine parts--Inspect the following components:
       - The camshaft--Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.
       - The cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical.
       - The pistons, etc.--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical.
    • Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearing Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions:
       - A no start
       - A start and stall
       - Erratic performance

Additional
    • Inspect for a restricted exhaust. Refer to Restricted Exhaust in Engine Exhaust.
    • Inspect the air intake ducts for being collapsed, damaged, loose, improperly installed, or leaking, especially between the MAF sensor and the throttle body.