Nissan Pathfinder 1996-05

Spark Plugs

Print

Inspection



Check the plugs for deposits and wear. Look carefully at the center electrode protrudes through the center of the porcelain. If the center electrode is eroded or rounded, replace the spark plugs. If the plugs 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 are sometimes found in service stations. These machines do a good job of cleaning the spark plug, although they tend to remove the protective anti-corrosive coating on the spark plug threads. They also cause the surface of porcelain around the center electrode to become slightly porous, allowing deposits to bond more easily to the porcelain. If a plug cleaner is used to clean the plugs, be sure the plug is thoroughly cleaned. The abrasive material used in the spark plug cleaners is very hard, and if allowed to enter the engine-s combustion chamber, could cause internal damage. An acceptable job of cleaning the spark plug can be accomplished by using a stiff wire brush. Once the plugs are cleaned, the spark plug gap must be checked and reset to specification.

Check spark plug gap before installation. Using a suitable spark plug gap gauge, check the spark plug gap. Make sure the L-shaped electrode connected to the body of the spark plug is parallel to the center electrode. If necessary, adjust the L-shaped electrode to attain the correct gap and proper alignment. Make sure to use the specified size wire gauge, which must pass between the electrodes with a slight drag and the next larger size should not be able to pass, while the next smaller size should pass freely. When adjusting a spark plug gap, always set the gap to the minimum specification to allow for electrode wear. Refer to the following information pertaining to spark plug gap.

Check, but do not adjust the spark plug gap. The spark plug gap should be 0.043 inches (1.1mm).


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 because the reading may be inaccurate. A round-wire type gapping tool is the best tool for checking the plug gap. The correct gauge should pass through the electrode gap with a slight drag. If 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 this to adjust the side electrode until the proper clearance is obtained. Never attempt to bend the center electrode. Be careful not to bend the side electrode too far or too often as it may weaken and break off inside the engine, requiring removal of the cylinder head to retrieve it.

Click image to see an enlarged view

Fig. Inspect the spark plug to determine engine running conditions



Click image to see an enlarged view

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



Click image to see an enlarged view

Fig. Checking the spark plug gap with a feeler gauge



Click image to see an enlarged view

Fig. Adjusting the spark plug gap



Click image to see an enlarged view

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

Removal & Installation



3.3L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Tag and disconnect the spark plug wires from spark plugs. Pull on the boot only - do not pull on the wire itself.
  4.  
  5. Remove spark plugs with 16 mm (0.63 in) spark plug wrench.

    Click image to see an enlarged view

    Fig. Use a suitable spark plug wrench to remove the spark plugs. Type -A- is for spark plugs except for No. 6 cylinder. Type -B- is for the No. 6 cylinder



    Click image to see an enlarged view

    Fig. Using the Type B spark plug wrench for the No. 6 cylinder

  6.  
  7. Inspect the spark plug and check the gap, as outlined under Inspection.
  8.  

To install:

  1. Install the spark plugs and tighten to 14-22 ft. lbs. (20-29 Nm).
    NOTE
    When installing spark plugs to No. 2 and 4 cylinders, securely fit each ignition wire mounting hole onto the ignition wire fixing pin.

  2.  
  3. Connect the spark plug wires to the spark plugs, as tagged during removal.
  4.  
  5. Connect the negative battery cable.
  6.  

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the throttle wires.
  6.  
  7. Remove the air duct with air cleaner assembly.
  8.  
  9. Disconnect harness connectors and harness brackets around ignition coil sides.
  10.  
  11. If removing the No. 4 spark plug, remove the throttle body as outlined in the Fuel System Section.
  12.  
  13. Disconnect the ignition coil harness connectors.
  14.  
  15. Loosen ignition coil mounting bolts and pull out coil from intake manifold connector.
  16.  
  17. Use a spark plug socket to remove the spark plug.
  18.  
  19. Inspect the spark plug and check the gap, as outlined under Inspection.

    Click image to see an enlarged view

    Fig. Left and right ignition coil banks-3.3L engine



    Click image to see an enlarged view

    Fig. Use a spark plug socket to remove the spark plugs

  20.  

To install:

  1. Install the spark plug and tighten to 14-22 ft. lbs. (20-30 Nm).
  2.  
  3. Install the ignition coil and tighten the retainers to 75-95 inch lbs. (8.5-10.7 Nm).
  4.  
  5. Attach the ignition coil harness connectors.
  6.  
  7. If the No. 4 spark plug was removed, install the throttle body.
  8.  
  9. Install the harness brackets and connectors.
  10.  
  11. Install the air cleaner assembly and air duct.
  12.  
  13. Install the throttle wires.
  14.  
  15. Install the engine cover.
  16.  
  17. Connect the negative battery cable.
  18.  

3.5L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the air duct with air cleaner assembly.
  6.  
  7. Disconnect the harness connectors and harness brackets around ignition coil sides.
  8.  
  9. Remove the electric throttle control actuator. (Only when removing the No. 4 cylinder spark plug)
  10.  
  11. Disconnect ignition coil harness connectors.
  12.  
  13. Loosen ignition coil mounting bolts and pull out coil from rocker cover.
  14.  
  15. Use a spark plug socket to remove the spark plug from the cylinder head.
  16.  
  17. Inspect the spark plug and check the gap, as outlined under Inspection.

    Click image to see an enlarged view

    Fig. Right bank ignition coil-3.5L engine



    Click image to see an enlarged view

    Fig. Left bank ignition coil-3.5L engine



    Click image to see an enlarged view

    Fig. Use a spark plug socket to remove the spark plugs

  18.  

To install:

  1. Install the spark plug and tighten to 15-22 ft. lbs. (20-30 Nm).
  2.  
  3. Install the ignition coil and tighten the retainers to 76-95 inch lbs. (8.5-10.8 Nm).
  4.  
  5. Attach the ignition coil harness connectors.
  6.  
  7. If the No. 4 spark plug was removed, install the electric throttle control actuator.
  8.  
  9. Install the harness brackets and connectors.
  10.  
  11. Install the air cleaner assembly and air duct.
  12.  
  13. Install the engine cover.
  14.  
  15. Connect the negative battery cable.
  16.  

4.0L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the ignition coil, as outlined in the Engine Electrical Section.

    Click image to see an enlarged view

    Fig. Ignition coil removal-4.0L engine

  4.  
  5. Remove the spark plug using a suitable spark plug socket.
    WARNING
    Do not drop or shock the spark plug if reusing it.



    Click image to see an enlarged view

    Fig. Remove the spark plug using a suitable spark plug socket

  6.  
  7. Inspect the spark plug and check the gap, as outlined under Inspection.
  8.  

To install:

  1. Install the spark plug and tighten to 15-22 ft. lbs. (20-30 Nm).
  2.  
  3. Install the ignition coil.
  4.  
  5. Connect the negative battery cable.
  6.  

 
label.common.footer.alt.autozoneLogo