Hard Start
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
- Observe the TB Idle Air Flow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to Throttle Body Cleaning .
- Test the engine coolant temperature (ECT) sensor. 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 . Replace the ECT sensor if the resistance is not within specification. Refer to Engine Coolant Temperature Sensor Replacement . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
- Verify the engine electrical system for correct operation. Refer to Symptoms - Engine Electrical .
- Verify that the driver is using the correct starting procedure as described in the owners manual.
- Verify that there is adequate fuel.
- Test the fuel pump relay operation. The fuel pump should turn ON for 2 s when the ignition is turned ON. Refer to Fuel System Diagnosis (NT7, NU1) or Fuel System Diagnosis (NU6) .
- Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to Crankshaft and Bearing Cleaning and Inspection .