GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 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 .
    • Refer to Visual/Physical Checks in Symptoms .
    • Search for bulletins.

Sensor/System
    • Inspect the engine coolant temperature (ECT) sensor for being shifted in value. Connect a scan tool and compare the ECT with the intake air temperature (IAT) on a cold engine. The ECT and 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 the Temperature Versus Resistance . If the ECT sensor resistance is within the specification, refer to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage or DTC P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage .
    •  Monitor the 18X Crankshaft Position and Camshaft Position Sensors on scan tool. If neither are responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all 18X and CMP sensor circuits for intermittents. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    •  Monitor the 3X parameter on the scan tool. If the 3X is not responding, inspect the 18X CKP Sensor and circuits for intermittents. Inspect the IC circuit, Bypass circuit, 3X Reference High Circuit, and the 3X Reference Low circuit for intermittents. If these circuits become open, or shorted a DTC may not set immediately, but driveability complaints can result. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    •  Inspect Mass Air Flow sensor for proper installation and conditions. A MAF sensor with a damaged honeycomb may cause a hard start. Refer to Information Sensors/Switches Description .
         Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.
    •  Using a scan tool, inspect the IAC operation. Refer to Idle Air Control (IAC) System Diagnosis .
    •  Inspect the EGR system for proper sealing/connections and operation. Refer to Exhaust Gas Recirculation (EGR) System Description .

Fuel System
    • Check the fuel pump relay circuit for proper operation.
        Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Check the fuel pressure.
        Refer to Fuel System Pressure Test (VIN K) .
    • Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System
    • Check for proper ignition voltage output using the following steps:
       - Clip the J 26792 spark tester to engine ground.
       - Connect one end of a spark plug wire to the J 26792 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 J 26792 spark tester. A spark should be observed.
       - Repeat the above steps for each coil.
    • If spark is not present at the plugs, check for the following conditions:
       - Inspect the coils for cracks, carbon tracking/arcing, or a secondary resistance value outside the specified range.

   Important: If carbon tracking is detected on one component, replace that component and the component's mate.

Coil Secondary Resistance
5000 - 8000 ohms (5K - 8K ohms)

       - Inspect the spark plug wires for signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, incorrect routing, or a resistance value more than the specified value.

Spark Plug Wires Resistance
1000 to 1500 ohms/ft.

   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 malfunctioning.

       - Check for a malfunctioning ignition control module.
       - Inspect the ignition system wiring for a loose ignition module feed, a poor ground connection, or damaged system wiring.
    • Remove the spark plugs.
    • Inspect the spark plugs for the following conditions:

   Important: If carbon tracking is detected on a component, replace that component and it's mate.

       - Check the spark plugs for signs of carbon tracking on the porcelain or arcing at the plug wire contact.
       - Check the spark plugs for incorrect gap.
       - Check the spark plugs for fouling.
       - Check the spark plug for cracks.
       - Check the spark plugs for burned or damaged electrodes.
       - Check the spark plugs for incorrect heat range. Refer to Maintenance Items .
    • 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 and leaking valve seals. Refer to Oil Consumption Diagnosis .
    • Low cylinder compression. Refer to Engine Compression Test .
    • For incorrect basic engine parts. Refer to Base Engine Misfire Diagnosis in Engine Mechanical. Inspect the following:
       - Cylinder heads
       - Camshaft and valve train components
       - Pistons, etc.