Checks
| Action
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DEFINITION: Engine cranks OK, but does not start for a long time. Does
eventually run, or may start but immediately dies.
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Preliminary
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Sensor/System
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• | Check for 24X Crankshaft position and Camshaft position sensors
on scan tool. If both are not responding, check the sensor feed circuit
(Both sensors use a common feed circuit). |
• | Check the EGR system for proper sealing/connections and operation.
Refer to EGR System Description
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Fuel System
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Ignition System
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• | Check for proper ignition voltage output using the following steps: |
- | Clip the J 26792
Spark
Tester to engine ground. |
- | Connect one end of a spark plug wire to the J 26792
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 J 26792
Spark Tester; a spark should be observed. |
- | Repeat the above steps for each coil. |
• | If 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 5000-8000ohms (5K-8Kohms) - | 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 600ohms per foot (1 968ohms per meter).
| 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.
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- | 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. Refer to
Spark Plug Visual Diagnosis
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Engine Mechanical
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• | Excessive oil in combustion chamber Leaking valve seals. Refer
to Oil Consumption Diagnosis
. |
• | Low cylinder compression. Refer to Engine Compression Test |
• | For incorrect basic engine parts. Inspect the following: |
- | Camshaft and valve train components |
- | Refer to Engine Mechanical. |
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