S10 Pickup, Sonoma 2000-2004

Spark Plugs

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Inspection



Spark Plug Visual Inspection


Normal operation--Brown to grayish-tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
 
Carbon Fouled--Dry, 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--Oil, 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.
 

Inspection & Gapping



  1. Inspect the terminal post for damage. Inspect for a bent or broken terminal post. Test for a loose terminal post by twisting and pulling the post. The terminal post should NOT move.
  2.  
  3. Inspect the insulator for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator between the terminal post 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.

    Click image to see an enlarged view

    Fig. Spark plug terminal post (1), insulator (2), side electrode (3), and center electrode

  4.  
  5. Inspect the insulator for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes.
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  7. Inspect for evidence of improper arcing. Measure the gap between the center electrode and the side electrode terminals. An excessively wide electrode gap can prevent correct spark plug operation.
  8.  
  9. Inspect for the correct spark plug torque. Insufficient torque can prevent correct spark plug operation. An over torqued spark plug, causes the insulator to crack.
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  11. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode.
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  13. Inspect for a broken or worn side electrode.
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  15. Inspect for a broken, worn, or loose center electrode by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode reduces the spark intensity. Inspect for bridged electrodes. Deposits on the electrodes reduces or eliminates the gap.
  16.  
  17. Inspect for worn or missing platinum pads on the electrodes, if equipped. Inspect for excessive fouling.
  18.  
  19. 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.
  20.  

Removal & Installation



2.2L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Remove all foreign material from around the spark plug holes.
  4.  
  5. Remove the spark plug wires.
  6.  
  7. Remove the spark plugs using a spark plug socket.
  8.  

To install:

  1. Using a round wire type spark plug gap gage, inspect the spark plug gap and adjust as necessary.
  2.  
  3. Install the spark plugs using the spark plug socket and tighten to 13 ft. lbs. (18 Nm).
  4.  
  5. Apply dielectric lubricant to the inside of the spark plug wire insulator boots.
  6.  
  7. Reinstall the spark plug wires.
  8.  
  9. Connect the negative battery cable.
  10.  

4.3L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect and label the spark plug wires.
  4.  
  5. Loosen each spark plug 1 or 2 turns.
  6.  
  7. Brush or air blast away any dirt from around the spark plugs.
  8.  
  9. Remove the spark plugs 1 at a time. Place each plug in a tray marked with the corresponding cylinder numbers.
  10.  

To install:

  1. Properly position each spark plug washer.
  2.  
  3. Inspect each spark plug gap. Adjust each plug to 1.524 mm (0.060 in).
  4.  
  5. Hand start the spark plugs in the corresponding cylinders.
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  7. Tighten the spark plugs. For used heads tighten the spark plugs to 11 ft. lbs. (15 Nm). For new aluminum heads tighten the spark plugs to 15 ft. lbs. (20 Nm). For new iron heads tighten the spark plugs to 22 ft. lbs. (30 Nm).
  8.  
  9. Install the spark plug wires.
  10.  
  11. Connect the negative battery cable.
  12.  

 
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