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 Important Preliminary Checks in
Symptoms |
• | Refer to Visual/Physical Checks in
Symptoms |
|
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
|
|
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 spark should
be observed. |
- | Repeat the above steps for each coil. |
• | If spark is not present at the coils, check for the following
conditions: |
| Important: If carbon tracking is detected on a component, replace that component
and its mate.
|
- | Coils - Cracks, carbon tracking/arcing, or a secondary 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 1000 to 1500 ohms/per ft.
| 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: |
- | Check the spark plugs for carbon tracking on the porcelain and
pitting on the plug wire contact. |
- | 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
|
• | For incorrect basic engine parts. Inspect the following: |
- | Camshaft and valve train components |
|