Hard Start
Checks
| Action
|
DEFINITION: Engine cranks OK, but does not start for a long time. The vehicle
does eventually run, or may start but immediately stalls.
|
Preliminary
|
• | Verify that the engine control module (ECM) grounds are clean, tight,
and in the correct locations. |
|
Sensor/System
|
• | Inspect 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
for resistance specifications.
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 circuits for a high resistance. |
|
Fuel System
|
|
Ignition System
|
• | Remove the spark plugs and inspect for the following conditions: |
- | Refer to the following procedures: |
• | If the spark plugs are fouled by gas, coolant, or oil, determine the cause
before replacing the plugs. Refer to the following procedures: |
- | For diagnosis of a rich condition, refer to
DTC P0172
. |
• | Verify that the ignition control module (ICM) ground is clean and tight. |
• | Inspect the ignition coil for tracks or carbon tracking. |
|
Engine Mechanical
|
• | Inspect for excessive oil in the combustion chamber and for leaking valve
seals. |
• | Inspect the combustion chambers for excessive carbon buildup. Clean the
chambers with top engine cleaner. Follow the instructions on the can. |
• | Inspect the following for incorrect basic engine parts: |
- | The pistons, connecting rods, and bearings |
- | Refer to the following
procedures in Engine Mechanical - 2.0L (L34GMDAT): |
|