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
Before Starting. |
• | 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
|
• | Test the fuel injectors using the following tests: |
|
Ignition System
|
• | Test 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 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 spark is not present at the coils, test for the following conditions: |
- | Coils -- Cracks, carbon tracking/arcing, or a secondary resistance
value outside the specified range. |
Coil Resistance 5,000-8,000 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 600 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 inspect 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
|
• | For incorrect basic engine parts. Inspect the following: |
- | Camshaft and valve train components |
|