Aura, Outlook 2007

Spark Plugs

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Inspection & Gapping



Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Remember that any kind of deposit will decrease the efficiency of the plug. Plugs can be cleaned on a spark plug cleaning machine, which can sometimes be found in service stations, or you can do an acceptable job of cleaning with a stiff brush. If the plugs are cleaned, the electrodes must be filed flat. Use an ignition points file, not an emery board or the like, which will leave deposits. The electrodes must be filed perfectly flat with sharp edges; rounded edges reduce the spark plug voltage by as much as 50%.

Check spark plug gap before installation. The ground electrode (the L-shaped one connected to the body of the plug) must be parallel to the center electrode and the specified size wire gauge (please refer to the Tune-Up Specifications chart for details) must pass between the electrodes with a slight drag.


NOTE
NEVER adjust the gap on a used platinum type spark plug.

Always check the gap on new plugs, as they are not always set correctly at the factory. Do not use a flat feeler gauge when measuring the gap on a used plug, because the reading may be inaccurate. A round-wire type gapping tool is the best way to check the gap. The correct gauge should pass through the electrode gap with a slight drag. If you're in doubt, try one size smaller and one larger. The smaller gauge should go through easily, while the larger one shouldn't go through at all. Wire gapping tools usually have a bending tool attached. Use that to adjust the side electrode until the proper distance is obtained. Absolutely NEVER attempt to bend the center electrode. Also, be careful not to bend the side electrode too far or too often, as it may weaken and break off within the engine, requiring removal of the cylinder head to retrieve it.

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Fig. A normally worn spark plug should have light tan or gray deposits on the firing tip



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Fig. A carbon fouled plug, identified by soft, sooty, black deposits, may indicate an improperly tuned vehicle. Check the air cleaner, ignition components and engine control system



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Fig. A variety of tools and gauges are needed for spark plug service



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Fig. A physically damaged spark plug may be evidence of severe detonation in that cylinder. Watch that cylinder carefully between services, as continued detonation will not only damage the plug, but could also damage the engine



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Fig. Checking the spark plug gap with a feeler gauge



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Fig. An oil fouled spark plug indicates an engine with worn piston rings and/or bad valve seals, allowing excessive oil to enter the chamber



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Fig. Adjusting the spark plug gap



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Fig. This spark plug has been left in the engine too long, as evidenced by the extreme gap. Plugs with such an extreme gap can cause misfiring and stumbling, accompanied by a noticeable lack of power



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Fig. If the standard plug is in good condition, the electrode may be filed flat-WARNING: do not file platinum plugs



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Fig. A bridged or almost bridged spark plug, identified by a build-up between the electrodes, caused by excessive carbon or oil build-up on the plug



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Fig. Used spark plugs which show damage may indicate engine problems

Removal & Installation



2.4L Engine
  1. Remove the intake manifold cover.
  2.  
  3. Disconnect the engine wiring harness electrical connectors from the ignition coil.
  4.  
  5. Remove the ignition coil bolt(s).
  6.  
  7. Remove the ignition coil(s).
  8.  
  9. Remove the spark plugs.
  10.  

To install:

  1. Installation is the reverse of removal. Tighten the spark plugs to 15 ft. lbs. (20 Nm) and the coil bolts to 89 in. lbs. (10 Nm).
  2.  

3.5L Engine
  1. Remove the intake manifold cover, if required.
  2.  
  3. Remove the air cleaner outlet duct, if required.
  4.  
  5. Remove the left side spark plug wires from the spark plugs, if required.
  6.  
  7. Remove the right side spark plug wires from the spark plugs, if required.
  8.  
  9. Remove the spark plugs from the engine.
  10.  

To install:


NOTE
It is important to check the gap of all new and reconditioned spark plugs before installation. Pre-set gaps may have changed during handling. Use a round wire feeler gauge to be sure of an accurate check, particularly on used plugs. Installing plugs with the wrong gap can cause poor engine performance and may even damage the engine.


NOTE
Be sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.

  1. Install the NEW spark plugs and tighten to 15 ft. lbs. (20 Nm).
  2.  
  3. Install the right side spark plug wires to the spark plugs, if required.
  4.  
  5. Install the left side spark plug wires to the spark plugs, if required.
  6.  
  7. Install the air cleaner outlet duct, if required.
  8.  
  9. Install the intake manifold cover, if required.
  10.  

3.6L Engine
  1. Remove the ignition coil(s).
    NOTE
    Clean the spark plug recess area before removing the spark plug. Failure to do so could result in engine damage because of dirt or foreign material entering the cylinder head, or by the contamination of the cylinder head threads. The contaminated threads may prevent the proper seating of the new plug. Use a thread chaser to clean the threads of any contamination.

  2.  
  3. Use compressed air in order to remove debris from the spark plug cavity.
    NOTE
    Allow the engine to cool before removing the spark plugs. Attempting to remove the spark plugs from a hot engine may cause the plug threads to seize, causing damage to cylinder head threads.

  4.  
  5. Remove the spark plug.
  6.  

To install:


NOTE
Use only the spark plugs specified for use in the vehicle. Do not install spark plugs that are either hotter or colder than those specified for the vehicle. Installing spark plugs of another type can severely damage the engine.


NOTE
Check the gap of all new and reconditioned spark plugs before installation. The pre-set gaps may have changed during handling. Use a round feeler gage to ensure an accurate check. Installing the spark plugs with the wrong gap can cause poor engine performance and may even damage the engine.

  1. Use a thread chaser, if necessary, to clean threads in the cylinder head. Cross-threading or failing to fully seat the spark plug can cause overheating of the plug, exhaust blow-by, or thread damage. Install the spark plug.
  2.  
  3. Be sure that the spark plug threads smoothly into the cylinder head and the spark plug is fully seated.
  4.  
  5. Tighten the spark plug to 15 ft. lbs. (20 Nm).
  6.  
  7. Install the ignition coil(s).
  8.  

 
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