GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Catera 🢒 Engine 🢒 Engine Electrical 🢒 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 - Engine Controls .
    • 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 skewed 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 mass air flow (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 (TP) sensors
       - Accelerator pedal position (APP) sensors
       - Throttle actuator
    • Verify the signal is present from the crankshaft position sensor (CKP). Refer to DTC P0335 .
    • Verify the signal is present from the camshaft position sensor (CMP). Refer to DTC P0340 .

Fuel System
    • Test the fuel pump relay operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Test for any of the following fuel pressure related problems. Refer to Fuel System 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 with Special Tool .

Ignition System
    • Test for proper ignition voltage output with J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis . 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 .
       - 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 Inspection . Once you determine the cause of the fouling, refer to one of the following procedures:
       - For diagnosis of a rich condition, refer to DTC P0172 or P0175 .
       - 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-3.0 (L81).

Engine Mechanical
    • Low cylinder compression--Refer to Engine Compression Test in Engine Mechanical-3.0 (L81).
    • 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-3.0 (L81).
    • Excessive oil in combustion chamber due to leaking valve seals--Refer to Oil Consumption Diagnosis in Engine Mechanical-3.0 (L81).
    • Inspect the following components for incorrect basic engine parts:
       - The cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical-3.0 (L81).
       - The camshafts--Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical-3.0 (L81).
       - The pistons, connecting rod, and/or bearings--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical-3.0 (L81).