Checks
| Actions
|
DEFINITION:
Fuel ignites in the intake manifold, or in the exhaust system, making loud
popping noise.
|
Preliminary Checks
|
| • | Refer to Important Preliminary Checks. |
| • | Refer to Visual/Physical Checks. |
|
Sensor/System
|
| • | Check for the following intermittent ignition system conditions: |
| - | Intermittent CKP Sync or CKP 18X Signal |
| - | Intermittent ignition feed circuit or sensor ground circuit to
the crankshaft position sensor or the camshaft position sensor |
| - | Intermittent 3X reference signal |
| - | Intermittent camshaft position signal |
| • | Check the throttle body inlet screen for foreign objects or damage
that can affect the MAF sensor airflow sample. |
|
Fuel System
|
| • | Check for incorrect fuel pressure. |
| • | Ensure each injector harness connector is connected to the correct
injector. |
|
Ignition System
|
| • | 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 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 adequate spark is not present at the coils, check for the following
conditions: |
| - | Coils - Cracks, carbon tracking/arcing, or a resistance value
outside the specified range. |
Coil Secondary Resistance
5000 - 8000 ohms (5K - 8K ohms) | - | Spark Plug wires - Signs of arcing/cross firing, cracks, carbon
tracking, plug boot damage, pinched, incorrect routing, or a resistance value
greater than the specified value. |
VIN 1 Spark Plug Wires Resistance
3280 - 4921 ohms per meter (1000 - 1500 ohms per foot).
VIN K Spark Plug Wires Resistance
3280 - 4921 ohms per meter (1000 - 1500 ohms per foot).
| | 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 malfunctioning.
|
| - | Malfunctioning ignition control module. |
| - | Ignition System Wiring - Loose ignition module feed or ground
connection, or damaged system wiring. |
| • | Remove spark plugs and check for the following conditions: |
| - | Burned or damaged electrodes |
| • | If spark plugs are gas or oil fouled, the cause of the fouling
must be determined before replacing the spark plugs. |
|
Engine Mechanical
|
| • | Check the engine for the following conditions: |
| - | Sticking or leaking valves |
| - | Excessive oil in combustion chamber - Leaking valve seals.
Refer to Oil Consumption Diagnosis
. |
| • | Inspect for the following incorrect engine parts: |
|
Additional Checks
|
| • | Check Intake and exhaust manifolds for casting flash. |
| • | Check the exhaust system for a possible restriction in one or
more of the following areas: |
| - | Damaged or collapsed pipes in the exhaust system |
| - | Heat distress or possible internal failure of the muffler |
| - | Possible plugged Three-Way catalytic converter |
|
