Chrysler Full-Size Vans 1989-1998 Repair Guide

Spark Plug Wires

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TESTING



See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Checking individual plug wire resistance with a digital ohmmeter

At every tune-up/inspection, visually check the spark plug cables for burns cuts, or breaks in the insulation. Check the boots and the nipples on the distributor cap and/or coil. Replace any damaged wiring.

Every 60,000 miles (96,000 km), the resistance of the wires should be checked with an ohmmeter.

Wires with excessive resistance will cause misfiring, and may make the engine difficult to start in damp weather.

  1. Disconnect the spark plug wire at the spark plug and the distributor.
  2.  
  3. Measure and note the length of the spark plug wire.
  4.  
  5. Using an ohmmeter, measure the resistance between the spark plug wire terminals.
  6.  
  7. Resistance should be less than 7000 ohms per foot of spark plug wire.
  8.  

If one spark plug wire is found to be out of specification, it is a good idea to replace the entire set.

  1. If resistance is excessive, the spark plug wire is faulty.
  2.  

REMOVAL & INSTALLATION



See Figure 2

  1. Label each spark plug wire and make a note of its routing.
  2.  

Don't rely on wiring diagrams or sketches for spark plug wire routing. Improper arrangement of spark plug wires will induce voltage between wires, causing misfiring and surging. Be careful to arrange spark plug wires properly.

  1. Starting with the longest wire, disconnect the spark plug wire from the spark plug and then from the distributor.
  2.  
  3. Remove the spark plug wire from the engine.
  4.  

To install:
  1. If replacing the spark plug wires, match the old wire with an appropriately sized wire in the new set.
  2.  
  3. Lubricate the boots and terminals with dielectric grease and install the wire on the distributor.
  4.  
  5. Route the wire in the exact path as the original and connect the wire to the spark plug.
  6.  
  7. Repeat the process for each remaining wire, working from the longest wire to the shortest.
  8.  
  9. When all wires are installed, check for proper routing and ensure that all terminals are securely connected.
  10.  
  11. Start the engine and check for proper performance.
  12.  



Click image to see an enlarged view

Fig. Fig. 2: To remove spark plug wires from the distributor cap, pull each wire's boot upward to remove from the cap tower

 
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