Chevrolet Sonic Repair Manual: Spark Plug Inspection
- Spark Plug Usage
-
- Ensure that the correct spark plug is installed. An
incorrect spark plug causes driveability conditions.
- Ensure that the spark plug has the correct heat range.
An incorrect heat range causes the following conditions:
- Spark plug fouling?older plug
- Pre-ignition causing spark plug and/or engine damage?otter plug
- Spark Plug Inspection
-
- Inspect the terminal post (1) for damage.
- Inspect for a bent or broken terminal post (1).
- Test for a loose terminal post (1) by twisting and pulling the post.
The terminal post (1) should NOT move.
- Inspect the insulator (2) for flashover or carbon tracking,
soot. This is caused by the electrical charge traveling across the insulator (2)
between the terminal post (1) and ground. Inspect for the following conditions:
- Inspect the spark plug boot for damage.
- Inspect the spark plug recess area of the cylinder head for moisture,
such as oil, coolant, or water. A spark plug boot that is saturated causes
arcing to ground.
- Inspect the insulator (2) for cracks. All or part of the
electrical charge may arc through the crack instead of the electrodes (3, 4).
- Inspect for evidence of improper arcing.
- Measure the gap between the center electrode (4) and the side electrode (3)
terminals. An excessively wide electrode gap can prevent correct spark plug
operation.
- Inspect for the correct spark plug torque. Insufficient torque can prevent
correct spark plug operation. An over torqued spark plug, causes the insulator (2)
to crack.
- Inspect for signs of tracking that occurred near the insulator tip instead
of the center electrode (4).
- Inspect for a broken or worn side electrode (3).
- Inspect for a broken, worn, or loose center electrode (4) by shaking
the spark plug.
- A rattling sound indicates internal damage.
- A loose center electrode (4) reduces the spark intensity.
- Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4)
reduce or eliminates the gap.
- Inspect for worn or missing platinum pads on the electrodes (3, 4) If
equipped.
- Inspect for excessive fouling.
- Inspect the spark plug recess area of the cylinder head for debris.
Dirty or damaged threads can cause the spark plug not to seat correctly
during installation.
- Spark Plug Visual Inspection
-
- Normal operation?rown to grayish-tan with small amounts
of white powdery deposits are normal combustion by-products from fuels with
additives.
- Carbon Fouled?ry, fluffy black carbon, or soot caused
by the following conditions:
- Rich fuel mixtures
- Leaking fuel injectors
- Excessive fuel pressure
- Restricted air filter element
- Incorrect combustion
- Reduced ignition system voltage output
- Weak coils
- Worn ignition wires
- Incorrect spark plug gap
- Excessive idling or slow speeds under light loads can keep spark plug
temperatures so low that normal combustion deposits may not burn off.
- Deposit Fouling?il, coolant, or additives that include substances such
as silicone, very white coating, reduces the spark intensity. Most powdery
deposits will not effect spark intensity unless they form into a glazing
over the electrode.
The Secondary Air Injection System aids in the reduction of hydrocarbon exhaust
emissions during a cold start. This occurs when the start-up engine coolant temperature
(ECT) is between −10 t ...
Spark Plug Replacement
Callout
Component Name
Preliminary Procedure
Open the hood.
Remove the engine sight shield.
Remove t ...
Other materials:
Communication Interface Module Battery Replacement
Communication Interface Module Battery Replacement
Callout
Component Name
Preliminary Procedure
Remove the instrument panel lower compartment. Refer to
Instrument Panel Lower Compartment Replacement
1
...
Engine Oil Pressure Indicator Switch Replacement
Engine Oil Pressure Indicator Switch Replacement
Callout
Component Name
1
Engine Oil Pressure Indicator Switch
Caution: Refer to Component Fastener
Tightening Caution.
Procedure
Place coll ...
Airbag Steering Wheel Module Replacement
Removal Procedure
Warning: Refer to SIR Inflator Module Handling and Storage
Warning.
Warning: Refer to SIR Warning.
Disable the SIR system. Refer to SIR Disabling and Enabling.
Rotate the steering wheel 180?€‰degrees.
Using a bl ...
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