Inspection/Test
| Action
|
DEFINITION: Engine cranks OK, but does not
start for a long time. Does eventually run, or may start but immediately
dies.
|
Preliminary
|
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Sensor/System
|
| • | Monitor the 24X crankshaft position (CKP) sensor and the camshaft
position (CMP) sensor on a scan tool. If both are not responding, test the
sensor feed circuit. Both sensors use a separate feed circuit but are internally
connected to power. Test all of the 24X sensor and all of the CMP sensor
circuits for intermittents. Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. |
| • | Monitor the 3X parameter on the scan tool. If the 3X is not responding,
inspect the 7X CKP sensor and the circuits for intermittents. Inspect the
ignition control (IC) circuit, the bypass circuit, the 3X reference high
circuit, and the 3X reference low circuit for intermittents. If these circuits
become open or shorted the circuits may not set a DTC immediately, but are
capable of causing driveability complaints. Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. |
| | Inspect the air intake ducts for collapsing, damaged areas, looseness,
improper installation, or leaking, especially between the MAF sensor and
the throttle body. |
|
Fuel System
|
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Ignition System
|
| • | Inspect for the proper ignition voltage output using the following
steps: |
| 1. | Attach the J 26792
spark tester to engine ground. |
| 2. | Connect the spark plug end of the spark plug wire to the J 26792
spark tester. Leave the
other end of the spark plug wire connected to the coil being tested. |
| 3. | Connect the spark plug end of the companion spark plug wire to
ground. |
The companion spark plug wire is the wire attached to the corresponding
coil tower.
| 4. | Crank the engine while observing the J 26792
spark tester. A crisp blue spark should be observed. |
| 5. | Repeat the above steps for each coil. |
| • | If spark is not present at the coils, inspect for the following
conditions: |
| - | Check the coils for cracks, carbon tracking or arcing, or a resistance
value outside the specified range. |
Coil Resistance
5000-8000 ohms | - | Check the spark plug wires for signs of arcing, cross firing,
cracks, carbon tracking, plug boot damage, pinching, improper routing, or
a resistance value outside the specified range. |
Spark Plug Wire Resistance
600 ohms per foot (1 968 ohms per meter).
| | Important: : Spraying the secondary ignition wires with a light mist of water may
help locate an intermittent problem. The ignition voltage will arc to ground
when a secondary component is faulty.
|
| - | Check for a faulty ignition module. |
| - | Check the ignition system wiring for a loose ignition module
feed or ground connection, or damaged system wiring. |
| • | Remove the spark plugs and inspect for the following conditions: |
| - | Burned or damaged electrodes |
| - | Improper heat range or reach |
| • | If the spark plugs are gas or oil fouled, the cause of the fouling
must be determined before replacing the spark plugs. Refer to
Spark Plug Visual Diagnosis
in Engine Electrical. |
|
Engine Mechanical
| Inspect or test for the following conditions:
| • | Any excessive oil in the combustion chamber and leaking valve
seals. Refer to
Oil Consumption Diagnosis
in Engine Mechanical. |
| • | Inspect the following components for incorrect basic engine parts: |
| - | The camshaft and the valve train components |
|
