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 the Powertrain OBD System Check |
| • | Refer to Important Preliminary Checks Before Starting. |
| • | Refer to Visual/Physical Checks |
|
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 the
Temperature vs. Resistance Table. If the ECT sensor resistance is not within
the specification, refer to DTC P0117 or DTC P0118 Diagnosis. |
| • | Check Mass Air Flow sensor for proper installation and conditions.
A MAF sensor with a damaged honeycomb may cause a hard start. Refer to MAF
Sensor Repair. |
| • | Using a scan tool, check IAC operation. Refer to Idle Air Control
(IAC) System Check. |
| • | Check the EGR system for proper sealing/connections and operation.
Refer to EGR System. |
|
Fuel System
|
| • | Check the fuel pump relay circuit for proper operation. Refer
to Fuel System Electrical Test. |
| • | Check for low fuel pressure. Refer to Fuel System Pressure Test. |
| • | Check for faulty fuel injectors. Refer to Fuel injector Coil/Fuel
Injector Balance test procedures. |
| • | Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel
Testing Procedure. |
|
Ignition System
|
| • | Check for proper ignition voltage output using the following steps: |
| - | Clip the spark tester J 26792 to engine ground. |
| - | Connect one end of a spark plug wire to the spark tester; leave
the other end of the spark plug wire to the coil being tested. |
| - | Connect one end of another spark plug wire to the other coil tower;
connect the other end of the spark plug wire to ground. |
| - | Crank the engine while observing the spark tester; a crisp blue
spark should be observed. |
| - | Repeat the above steps for each coil. |
| • | If adequate spark is not present at the coil(s), check for the
following conditions: |
| - | Coil(s) - Cracks, carbon tracking/arcing, or a resistance value
outside the specified range. |
Coil Resistance
5000 - 8000 ohms (5K - 8K ohms) | - | Spark Plug wires - Signs of arcing/cross firing, cracks, carbon
tracking, plug boot damage, pinched, improper routing, or a resistance value
outside the specified range. |
Spark Plug Wire Resistance
7000 ohms (7K ohms)
| | Important: Spraying the secondary ignition wires with a light mist of water may
help locate an intermittent problem. Ignition components will arc to ground
when a secondary component is faulty.
|
| - | Ignition System Wiring - Loose ignition module feed or ground
connection, or damaged system wiring. |
| • | Remove spark plugs and check for the following: |
| - | Burned or damaged electrodes |
| - | Improper heat range or reach |
| • | If spark plugs are gas or oil fouled, the cause of the fouling
must be determined before replacing the spark plugs. |
|
Engine Mechanical
|
| • | Excessive oil in combustion chamber-Leaking valve seals.
Refer to Engine Mechanical.
|
| • | Low cylinder compression. Refer to Engine Mechanical.
|
| • | For incorrect basic engine parts. Inspect the following: |
| - | Camshaft and valve train components |
| - | Refer to Engine Mechanical.
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