Mazda Trucks 1987-1993 Repair Guide

Ignition Coil Pack

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TESTING



Primary and Secondary Circuit Tests

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Distributorless ignition system diagram

  1. Turn the ignition switch OFF , disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
  2.  
  3. Check for dirt, corrosion or damage on the terminals.
  4.  

PRIMARY RESISTANCE

See Figure 1

  1. Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the resistance:

    B+ to Coil 1
     
    B+ to Coil 2
     
    B+ to Coil 3
     

  2.  

The resistance between all of these terminals should have been between 0.3-1.0 ohms. If the resistance was more or less than this value, the coil should be replaced with a new one.

SECONDARY RESISTANCE

See Figure 1

  1. Measure, using the ohmmeter, and note the resistance between each corresponding coil terminal and the two spark plug wire towers on the ignition coil. The coil terminals and plug wires towers are grouped as follows:
  2.  

4.0L engine



Terminal 3 (coil 1)-spark plugs 1 and 5
 
Terminal 2 (coil 3)-spark plugs 2 and 6
 
Terminal 1 (coil 2)-spark plugs 3 and 4
 

If the resistance for all of the readings was between 6,500-11,500 ohms, the ignition coils are OK. If any of the readings was less than 6,500 ohms or more than 11,500 ohms, replace the corresponding coil pack.

REMOVAL & INSTALLATION



See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: Ignition coil pack mounting

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the electrical harness connector from the coil pack.
  4.  
  5. Remove the spark plug wires by squeezing the locking tabs to release the coil boot retainers.
  6.  
  7. Remove the coil pack retaining bolts and remove the coil pack.
  8.  
  9. Place the coil pack in position and install the retaining bolts. Tighten the bolts to 40-62 inch lbs. (4.5-7.0 Nm).
  10.  

Be sure to place some dielectric compound into each spark plug boot prior to installation of the spark plug wire.

 
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