Mazda Trucks 1994-1998 Repair Guide

Spark Plug Wires

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TESTING



Only test one spark plug wire at a time. When the check is complete return the plug wire to its original location. If the wire is defective and more wires are to be checked, mark the wire as such, return it to its original location, then inspect the other wires. Once all of the wires are checked, replace the defective wires one at a time. This will avoid any mix-ups.

With Distributor

See Figure 1



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Fig. Fig. 1: Testing the spark plug wire resistance through the distributor cap with an ohmmeter

  1. Remove the distributor cap from the distributor assembly.
  2.  
  3. Visually inspect the spark plug wires for burns, cuts or breaks in the insulation. Check the spark plug boots and the nipples on the distributor cap and coil. Replace any damaged wiring.
  4.  
  5. Inspect the spark plug wires to insure that they are firmly seated on the distributor cap.
  6.  
  7. Disconnect the spark plug wire thought to be defective at the spark plug.
  8.  
  9. Using an ohmmeter, measure the resistance between the distributor cap terminal and the spark plug terminal.
  10.  

Make certain that a good connection exists between the distributor cap and the spark terminal. Never, under any circumstances, measure resistance by puncturing the spark plug wire.

  1. If the measured resistance is less than 7000 ohms per foot of wire, the wire is good. If the measured resistance is greater than 7000 ohms per foot, the wire is defective and should be replaced.
  2.  

Without Distributor

See Figure 2

  1. Visually inspect the spark plug wires for burns, cuts or breaks in the insulation. Check the spark plug boots and the nipples on the coil. Replace any damaged wiring.
  2.  
  3. Inspect the spark plug wires to insure that they are firmly seated on the coil pack.
  4.  
  5. Disconnect the spark plug wire thought to be defective at the spark plug.
  6.  
  7. Using an ohmmeter, measure the resistance between the coil terminal and the spark plug terminal.
  8.  



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Fig. Fig. 2: Checking individual plug wire resistance with a digital ohmmeter

Never, under any circumstances, measure resistance by puncturing the spark plug wire.

  1. If the measured resistance is less than 7000 ohms per foot of wire, the wire is good. If the measured resistance is greater than 7000 ohms per foot, the wire is defective and should be replaced.
  2.  

REMOVAL & INSTALLATION



See Figures 3, 4 and 5

When removing spark plug wires, use great care. Grasp and twist the insulator back and forth on the spark plug to free the insulator. Do not pull on the wire directly as it may become separated from the connector inside the insulator.



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Fig. Fig. 3: Note that the spark plug wires and distributor cap are numbered for correct wiring placement at the factory (C refers to ignition coil wire)



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Fig. Fig. 4: Be sure to number all the spark plug wires to the correct terminal on the distributor cap before disconnecting them



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Fig. Fig. 5: Using a spark plug wire removal tool

To install:

Whenever a high tension wire is removed for any reason form a spark plug, coil or distributor terminal housing, silicone grease must be applied to the boot before it is reconnected. Using a small clean tool, coat the entire interior surface of the boot with silicone grease or an equivalent.

  1. Install each wire in or on the proper terminal of the coil pack or distributor cap. Be sure the terminal connector inside the insulator is fully seated. The No. 1 terminal is identified on the cap.
  2.  
  3. Remove wire separators from old wire set and install them on new set in approximately same position.
  4.  
  5. Connect wires to proper spark plugs. Be certain all wires are fully seated on terminals.
  6.  

 
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