GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Rendezvous - FWD 🢒 Engine 🢒 Engine Controls - 3.6L (LY7) 🢒 Hard Start

Inspections

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 Starting in Symptoms - Engine Controls .
    • Inspect the engine control system grounds for being clean, tight, and in the correct locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . Ensure the resistance between the engine control module (ECM) housing and the battery negative cable is less than 0.5 ohms.
    • Verify that the ECM and ECM bracket fasteners are at the correct torque.
    • Search for service bulletins that may address this condition.

Sensor/System
    • Confirm the correct operation of the theft deterrent system. Refer to Symptoms - Theft Deterrent in Theft Deterrent.

       Important: Allow the engine to cool before performing this test.

    • Inspect the engine coolant temperature (ECT) sensor for being skewed in value. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor for resistance specifications. Replace the ECT sensor if the resistance is not within the specification. Refer to Engine Coolant Temperature Sensor Replacement . If the sensor is within the specification, repair the high resistance in the ECT signal circuit.
    • Inspect the crankshaft position (CKP) sensor for the correct resistance. The sensor resistance may be out of range after a hot soak. Measure that the resistance remains within 700-1,200 ohms at all temperatures.

Fuel System
    • Test the fuel pump relay operation. The fuel pump should turn ON for 2 seconds when the ignition is turned ON. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Test for incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Test for a restricted fuel filter. Refer to Fuel System Diagnosis .
    • Test for leaking fuel injectors. Refer to Fuel System Diagnosis .
    • Test for plugged or restricted injectors. Refer to Fuel Injector Balance Test with Special Tool .
    • Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System
    • Inspect for the correct installation of the ignition coil seals. Incorrect installation may allow water to enter the spark plug area. Inspect for moisture and corrosion.
    • Test the ignition voltage output with J 26792 Spark Tester. If you suspect an ignition system condition exists, 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 the following procedures:
    • If the spark plugs are gas, coolant or oil fouled, determine the cause before replacing the spark plugs. Refer to the following procedures:
       - For diagnosis of a rich condition, refer to DTC P2178 or DTC P2188 .
       - For diagnosis of coolant contaminated spark plugs, refer to Loss of Coolant in Engine Cooling.
       - For diagnosis of oil fouled spark plugs, refer to Oil Consumption Diagnosis in Engine Mechanical - 3.6L (LY7).
    • Inspect the spark plug boots and terminals for burning or micro-arcing, corrosion, and damage to the insulation.

Engine Mechanical
    • Inspect for the following engine mechanical conditions:
       - Excessive oil in combustion chamber or leaking valve seals
       - Low cylinder compression
       - Sticking or leaking valves
       - Worn camshaft lobes
       - Camshaft timing
       - Broken valve springs
       - Excessive carbon buildup in the combustion chambers. Clean the chambers with top engine cleaner. Follow the instructions on the can.
       - For more information, refer to the following procedures in Engine Mechanical - 3.6L (LY7):
    • Inspect the following components for incorrect basic engine parts:
       - Camshafts
       - Cylinder heads
       - Pistons, connecting rods, or bearings.
       - Refer to the following procedures in Engine Mechanical - 3.6L (LY7):