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
Symptoms
, Important
Preliminary Checks Before Starting. |
| • | Check PCM grounds for being clean, tight and in their proper locations. |
|
Sensor/System
|
| • | Check Engine Coolant Temperature (ECT) sensor for being shifted
in value. Connect a Scan Tool and compare Engine Coolant Temperature with
Intake Air Temperature on a cold engine. The ECT and IAT should be within
± 3°C (5°F) of each other. Check the resistance of the ECT
sensor if the temperature is out of range with the IAT sensor. Refer to Temperature vs Resistance
for resistance
specifications. Replace ECT sensor if the resistance is not within the
specification. If the sensor is within the specification, repair ECT signal
circuit for high resistance. |
| • | Check Mass Air Flow sensor installation. |
| • | Using a Scan Tool, monitor TP sensor voltage. The TP sensor voltage
should be less then 0.9 volts at rest. If the TP sensor voltage is greater
than 0.9 volt, inspect the throttle body and accelerator cables for binding. |
| • | Check the EGR system for proper operation. |
|
Fuel System
|
| • | Check fuel pump relay operation - pump should turn on for
2 seconds when ignition is turned on. |
| • | A faulty in-tank fuel pump check valve will allow the fuel
in the lines to drain back to the tank after the engine is stopped. To check
for this condition, refer to the
Fuel System Pressure Test
. |
| • | Check the injector fuse(s) for being open. Replace the fuse if
necessary and inspect the injector circuits for an intermittent short to ground. |
| • | Check for low fuel pressure. |
| • | Check for a restricted fuel filter. |
|
Ignition System
| Remove the spark plugs and check for the following:
If the spark plugs are gas or oil fouled, the cause of the fouling must
be determined before replacing the spark plugs.
| • | Check the plugs/coils for signs of arcing or carbon tracking. |
| • | Check for loose Ignition Control module grounds. |
| • | Check the spark plugs for proper heat range. |
|
Engine Mechanical
| Check for the following conditions:
| • | Excessive oil in the combustion chamber may indicate leaking valve
seals. Refer to Oil Consumption Diagnosis
. |
| • | Low cylinder compression. Refer to Engine Compression Test
. |
| • | Combustion chambers for excessive carbon buildup. Clean using
Top Engine cleaner. Follow the instructions on the container. |
| • | Incorrect basic engine parts. Inspect the following: |
Refer to Base Engine Misfire Diagnosis
.
|
Additional Checks
| Using a scan tool, check IAC operation and Typical Scan
Data values.
|
