Chrysler Full-Size Trucks 1997-2000 Repair Guide

Spark Plug Wires

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TESTING





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Fig. 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 50,000 miles (80,000 Km) or 60 months, 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.

Minimum spark plug wire resistance should be 250 ohms per inch (635 ohms per centimeter) and maximum resistance should be 1,000 ohms per inch (2,540 ohms per centimeter).

REMOVAL & INSTALLATION




NOTE
The vehicles covered in this guide may have heat shields, which were installed by the manufacturer, located around the spark plugs. These are designed to protect the spark plug boots from the intense heat of the exhaust manifold. If they are still in place, do NOT remove them. If they are not in place, be sure to inspect the boots more frequently.

  1. Mark all the spark plug wires near the cap with their cylinder number for identification purposes. On some models factory wires have the cylinder number already on them.
  2.  
  3. Grasp and twist the spark plug boot until the boot comes free of the plug. Do NOT pull on the wire.
  4.  
  5. Repeat the above process for the other spark plug wires.
  6.  



Click image to see an enlarged view

Fig. These heat shields, which were installed by the manufacturer, are designed to protect the spark plug boots from the intense heat of the exhaust manifold. If they are still in place, do NOT remove them. If they are not in place, be sure to inspect the boots more frequently

To install:

  1. When installing a new set of spark plug cables, replace the cables one at a time so there will be no mix-up. Start by replacing the longest cable first. Install the boot firmly over the spark plug. Route the wire exactly the same as the original. Insert the nipple firmly into the tower on the distributor cap.
  2.  
  3. Repeat the process for each cable.
  4.  

 
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