Checks
| Action
|
DEFINITION: The
engine cranks OK, but does not start for a long time. The engine does eventually
run, or it may start but immediately stall.
|
Preliminary
|
• | Refer to Important Preliminary Checks Before Starting. |
• | Refer to Visual/Physical Checks. |
|
Sensor/System
|
• | Monitor the 18X Crankshaft Position and Camshaft Position Sensors
on scan tool. If neither are responding, test the sensor feed circuit. Both
sensors use a separate feed circuit but are internally connected to power.
Test all 18X and 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 18X CKP Sensor and circuits for intermittents. Inspect the IC
circuit, Bypass circuit, 3X Reference High Circuit, and the 3X Reference
Low circuit for intermittents. If these circuits become open, or shorted
a DTC may not set immediately, but driveability complaints can result. Refer
to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. |
| Inspect the air intake ducts for being collapsed, damaged areas, looseness,
improper installation, or leaking especially between the MAF sensor and
the throttle body. |
|
Fuel
System
|
• | Test the fuel injectors using the following tests: |
|
Ignition
System
|
• | Test 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, and
leave the other end of the spark plug wire to the coil that is being tested. |
- | Connect one end of another spark plug wire to the other coil tower,
and connect the other end of the spark plug wire to ground. |
- | Crank the engine while observing the spark tester. You should
observe a crisp blue spark. |
- | Repeat the above steps for each coil. |
• | If spark is not present at the coils, test for the following conditions: |
- | The coils--Inspect for cracks, carbon tracking/arcing, or
a secondary resistance value outside the specified range. |
Coil Resistance 5,000-8,000 ohms (5K-8K ohms) - | The spark plug wires--Inspect for signs of arcing/cross firing,
cracks, carbon tracking, plug boot damage, pinches, improper routing, or for
a resistance value that is outside the specified range. |
Spark Plug Wire Resistance 600 ohms per ft.
| Important: Spraying the secondary ignition wires with a light mist of water may
help to locate an intermittent problem. The ignition components
will arc to ground when a secondary component is faulty.
|
- | The ignition system wiring--Check for a loose ignition module
feed or ground connection, or for damaged system wiring. |
• | Remove spark plugs and inspect for the following: |
- | Burned or damaged electrodes |
- | Improper heat range or reach |
• | If spark plugs are gas or oil fouled, determine the cause of the
fouling before you replace the spark plugs. |
|
Engine
Mechanical
|
• | Excessive oil in combustion chamber--Check for leaking valve
seals. Refer to Oil Consumption Diagnosis
in
Engine Mechanical. |
• | Check for incorrect basic engine parts. Inspect the following: |
- | The camshaft and valve train components |
- | The valve train components |
- | Other engine parts, as applicable |
|