Checks
| Action
|
DEFINITION: The engine cranks, but the engine does not
start for a long time. The engine does eventually run, or the engine may
start, but immediately quit.
|
Preliminary
|
| • | Inspect the powertrain control module (PCM) grounds. Ensure that
they are clean, tight, and in the proper locations. Refer to
Engine Controls Schematics
. |
|
Sensor/System
|
| • | Test the engine coolant temperature (ECT) sensor for being shifted
in value. Connect a scan tool. Compare the Engine Coolant Temperature to
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
for
resistance specifications. If the resistance is not within the specification,
replace the ECT sensor . If the sensor is within the specification,
repair ECT signal circuit for high resistance. |
| • | Inspect the mass air flow (MAF) sensor installation. A MAF sensor
that is incorrectly installed may cause a hard start. 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. Refer to
Mass Airflow Sensor Replacement
. |
| • | If the PCM does not receive a CMP signal, the Camshaft Position
Sensor (CMP) may cause a long engine crank time. |
|
Fuel System
|
| • | A faulty in-tank fuel pump check valve allows the fuel in the
lines to drain back to the tank after the engine stops. In order to test for
this condition, refer to
Fuel System Diagnosis
. |
| • | Inspect both injector fuses for being open. An open injector fuse
causes 4 injectors and 4 ignition coils not to operate. Replace
the fuse. Inspect the injector circuits and the ignition
coil circuits for an intermittent short to ground. |
|
Ignition System
|
| • | Inspect both injector fuses for being open. An open injector fuse
causes 4 ignition coils and 4 injectors to not operate. Replace
the fuse. Inspect the ignition coil circuits. Inspect the injector
circuits for an intermittent short to ground. |
| • | Remove the spark plugs. Inspect for the following conditions: |
| • | Before you replace the spark plugs, determine the cause of the
fouling. If the spark plugs are fouled, refer to the procedures below: |
|
Engine Mechanical
| Inspect for the following conditions:
| • | Excessive oil in the combustion chamber caused by leaking valve
seals--Refer to
Oil Consumption Diagnosis
in Engine Mechanical-5.7L. |
| • | Excessive carbon buildup in the combustion changers--Clean
the chambers using top engine cleaner. Follow the instructions on the can. |
| • | Incorrect basic engine parts--Inspect the following components: |
|
