GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Catera 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 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 .
    • Inspect the ECM grounds for being clean, tight and in the proper locations. Refer to Engine Controls Schematics .
    • Search for service bulletins that may address this condition.

Sensor/System
    • Confirm the correct operation of the theft deterrent system. Refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent.
    • Inspect the engine coolant temperature (ECT) sensor for being shifted in value. Connect a scan tool. Compare the ECT against the intake air temperature (IAT) on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F) of each other. 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.

       Important: The embossed arrows on the MAF sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Install the MAF in the proper direction.

    • Inspect the MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .
    • Verify the proper operation of the following throttle control system components. Use scan tool data display and special functions to actuate the system.
       - Throttle position sensors
       - Accelerator pedal position sensors
       - Throttle actuator
    • Verify the signal is present from the crankshaft position sensor. Refer to DTC P0335 Crankshaft Position (CKP) Sensor Circuit .
    • Verify the signal is present from the camshaft position sensor. Refer to DTC P0340 Camshaft Position (CMP) Sensor Circuit .

Fuel System
    • Test the fuel pump relay operation. Refer to Fuel Pump Circuit Diagnosis .
    • Test for any of the following fuel pressure related problems. Refer to Fuel System Diagnosis for diagnosis.
       - An inoperative check valve in the fuel pump allowing the fuel in the lines to drain back to the tank after the engine stops
       - Incorrect fuel pressure
       - Restricted fuel filter
    • Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Test for plugged or restricted injectors. Refer to Fuel Injector Balance Test .

Ignition System
    • Test for proper ignition voltage output with J 26792 spark tester. Refer to Ignition System Check . If you suspect secondary ignition system leakage, perform the procedure located in the Diagnostic Aids portion of the Ignition System Check.
    • Remove the spark plugs and inspect for the following conditions. Refer to Spark Plug Replacement in Engine Electrical.
       - Correct heat range
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits
    • Determine the cause of the fouling before replacing the spark plugs if the spark plugs are gas, coolant or oil fouled. Refer to Spark Plug Visual Diagnosis .
       - For diagnosis of a rich condition, refer to DTC P0172 Fuel Trim System Rich Bank 1 or DTC P0175 Fuel Trim System Rich Bank 2 .
       - 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.

Engine Mechanical
    • Low cylinder compression. Refer to Engine Compression Test in Engine Mechanical.
    • Combustion chambers for excessive carbon buildup. Clean the chambers using top engine cleaner. Follow the instructions on the can.
    • Check for incorrect camshaft timing. Refer to Timing Belt Timing Adjustment in Engine Mechanical.
    • Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • For incorrect basic engine parts, inspect the following:
       - The cylinder heads, refer to Cylinder Head Cleaning and Inspection in Engine Mechanical.
       - The camshafts, refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.
       - The pistons, connecting rod, and/or bearings, refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical.