GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1997 🢒 Skylark 🢒 Engine 🢒 Engine Controls - 3.1L 🢒 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 .
    • Refer to Visual/Physical Checks .
    • Search for bulletins.

Sensor/System
    • Check Engine Coolant Temperature (ECT) sensor for being shifted in value. Connect a Scan Tool and compare Engine Coolant Temperature with Intake Air Temperature on a cold engine. The ECT and 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 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage or DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage .
    • Check the throttle body inlet screen for foreign objects or damage that may affect the MAF sensor airflow sample. Refer to Throttle Body Assembly Replacement .
    • Using a scan tool, check IAC operation. Refer to Idle Air Control (IAC) System Check .
    • EGR system. Check the for the following conditions:
       - EGR pipes and adapter for vacuum leaks.
       - Remove the EGR valve and check for a stuck open pintle. Refer to Exhaust Gas Recirculation Valve Replacement .

Fuel System
    • 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 Pressure Test .
    • Check the fuel injectors. Refer to Fuel Injector Solenoid Coil Test .
    • Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Test .

Ignition System
    • Check for proper ignition voltage output using the following steps:
       - Clip the spark tester J 26792 to engine ground.
       - Connect one end of a spark plug wire to the spark tester; leave the other end of the spark plug wire to the coil being tested.
       - Connect one end of another spark plug wire to the other coil tower; connect the other end of the spark plug wire to ground.
       - Crank the engine while observing the spark tester; a crisp blue spark should be observed.
       - Repeat the above steps for each coil.
    • If adequate spark is not present at the coil(s), check for the following conditions:
       - Coil(s) - Cracks, carbon tracking/arcing, or a resistance value outside the specified range.

Coil Resistance
5000 - 7000 ohms (5K - 7K ohms)

       - Spark Plug wires - Signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range.

Spark Plug Wire Resistance
Less than 7000 ohms (7K ohms)

   Important: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition components will arc to ground when a secondary component is faulty.

       - Defective module.
       - Ignition System Wiring - Loose ignition module feed or ground connection, or damaged system wiring.
    • Remove spark plugs and check for the following conditions:
       - Fouled plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned or damaged electrodes
       - Improper heat range or reach
    • If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Engine Mechanical
    • Excessive oil in combustion chamber-Leaking valve seals. Refer to Engine Mechanical.
    • Low cylinder compression. Refer to Engine Mechanical.
    • For incorrect basic engine parts. Inspect the following:
       - Cylinder heads
       - Camshaft and valve train components
       - Pistons, etc.
       - Refer to Engine Mechanical.