Avalon 1995-1996

Spark Plugs

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Inspection



Specific to:

Toyota Avalon 1995-1996

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. All Toyota spark plugs from the manufacture are already pregappped, but do not assume that the gap is correct, check them anyway prior to 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 a 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-CAUTION: 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



Specific to:

Toyota Avalon 1995-1996

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the V-bank cover (engine appearance cover), as applicable.
  6.  
  7. Disconnect the ignition coil/spark plug, as applicable.
  8.  
  9. Using a spark plug wrench, remove the spark plugs.
  10.  

To install:

  1. Installation is the reverse of removal. Tighten the spark plugs to 13 ft. lbs. (18 Nm).
  2.  

 
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