GM Metro/Sprint 1985-1993 Repair Guide

Spark Plug Wires

Print

See Figure 1

Every 15,000 miles, 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.

Every 30,000 miles or so, 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. Generally, the useful life of the spark plug wires is 30,000-45,000 miles.

To check spark plug wire resistance, remove the distributor cap, leaving the wires in place. Connect one lead of an ohmmeter to an electrode within the cap; connect the other lead to the corresponding spark plug terminal (remove it from the spark plug for this test). Replace any wire which shows a resistance over 3-6.7 ohms per foot.

REMOVAL & INSTALLATION





Click image to see an enlarged view

Fig. Fig. 1: Measuring secondary wire resistance

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the coil wire from the ignition coil. Gripping the boot firmly, turn the boot 1 / 2 turn and disconnect the wire. 1 / 2 turn and disconnect the wire.
  4.  
  5. Remove the spark plug wire retainers from the engine.
  6.  
  7. Label and remove the spark plug wires from the spark plugs. Gripping the boot firmly, turn the boot 1 / 2 turn and disconnect the wire. 1 / 2 turn and disconnect the wire.
  8.  
  9. Remove the screws retaining the distributor cap.
  10.  
  11. Remove the distributor cap and wires as an assembly.
  12.  
  13. Measure the resistance between the distributor cap terminals and the spark plug wire terminals using an ohmmeter. If the resistance is greater than 3-6.7 ohms per foot of spark plug wire, replace the wire.
  14.  

If one or more wires show a resistance out of specification, it is recommended that the entire set of wires be replaced.

  1. Remove the spark plug wire from the distributor and replace it with one of the correct length.
  2.  

To install:
  1. Install the new spark plug wire to the distributor cap after coating the inside of the boots with dielectric grease.
  2.  
  3. Install the distributor cap to the distributor and secure with screws.
  4.  
  5. Install the spark plug wires to the spark plugs. Ensure that the spark plug boots are coated inside with dielectric grease.
  6.  
  7. Reposition the spark plug wires and install the wire retainers on the engine.
  8.  
  9. Connect the coil wire to the ignition coil.
  10.  
  11. Connect the negative battery cable.
  12.  

 
label.common.footer.alt.autozoneLogo