GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Impala 🢒 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 in Symptoms Before Starting.
    • 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 for low fuel pressure. Refer to Fuel System Pressure Test (VIN K) .
    • Check for faulty fuel injectors using the following procedures:
       -  Fuel Injector Balance Test
    • Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis Procedure.

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 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 spark should be observed.
       - Repeat the above steps for each coil.
    • If spark is not present at the plug, check for the following conditions:
       - Coils - Cracks, carbon tracking/arcing, or a secondary resistance value outside the specified range.

Coil Resistance
5000-8000 ohms (5K-8K 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
600 ohms per/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 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 reasons:
       - Fouled plugs
       - Cracks

   Important: If carbon tracking is detected on any component replace that component and it's mate. Carbon tracking on the porcelain and pitting on the plug wire contact.

       - Improper gap
       - Burned or damaged electrodes
       - Improper heat range or reach - refer to Spark Plug Usage
    • 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.
    • Low cylinder compression
    • For incorrect basic engine parts inspect the following components:
       - Cylinder heads
       - Camshaft and valve train components
       - Pistons, etc.
       - Refer to Oil Consumption Diagnosis or Engine Compression Test in Engine Mechanical.