Mazda Trucks 1987-1993 Repair Guide

Ignition Coil

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TESTING



See Figures 1, 2, 3 and 4

  1. Connect an ohmmeter across the coil primary terminals and check resistance on the low scale. Resistance (@ 68°F; 20°C) should be:
  2.  

Pickups:


1987-89 B2200 carbureted: 1.0-1.3 ohms
 
1990-93 B2200 injected: 0.81-0.99 ohms
 
1987-88 B2600: 1.0-1.3 ohms
 
1989 B2600i; Point 1: 0.77-0.95 ohms ; Point 2: 0.9-1.1k ohms
 
1990-93 B2600i: 0.81-0.99 ohms
 



Click image to see an enlarged view

Fig. Fig. 1: Ignition coil primary resistance test-2.2L carbureted engine (left), 2.6L fuel injected engine (right)



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Fig. Fig. 2: Checking the primary ignition coil reesistance-3.0L engine

MPV


2.6L engine; Point 1: 0.77-0.95 ohms ; Point 2: 0.9-1.1k ohms
 
1989-91 3.0L engine: 0.81-0.99 ohms
 
1992-93 3.0L engine: 0.72-0.88 ohms
 

  1. If resistance is much higher, replace the coil.
  2.  
  3. Check the coil secondary resistance.Connect an ohmmeter across the distributor side of the coil and the coil center tower. Read resistance on the high scale. Resistance at 68°F; 20°C) should be:
  4.  

Pickups



1987-88 B2200: 6-30k ohms
 
1987-88 B2600: 10-20k ohms
 
1989-93 B2200 and B2600i: 6-30k ohms
 



Click image to see an enlarged view

Fig. Fig. 3: Ignition coil secondary resistance test-Coil for carbureted engine shown

MPV


1989-93 2.6L engine-Point 1: 0.77-0.95 ohms ; Point 2: 0.9-1.1k ohms
 
1989-91 3.0L engine: 0.81-0.99 ohms
 
1992-93 3.0L engine: 0.72-0.88 ohms
 

  1. If resistance is much higher, replace the coil.
  2.  
  3. Disconnect the high tension wire and move the connector leading to the negative terminal over to the metallic connector inside the coil tower. Set the ohmmeter to the X1000 scale. Resistance must be:
  4.  

Pickups



1987-88 B2200: 6-30k ohms
 
1987-88 B2600: 10-20k ohms
 
1989-93 B2200 and B2600i: 6-30k ohms
 



Click image to see an enlarged view

Fig. Fig. 4: Checking the ignition coil secondary resistance-3.0L engine (MPV)

MPV


2.6L engine; Point 1: 0.77-0.95 ohms ; Point 2: 0.9-1.1k ohms
 
1989-91 3.0L engine: 0.81-0.99 ohms
 
1992-93 3.0L engine; 0.72-0.88 ohms
 

  1. You can also check for bad coil insulation by measuring the resistance between the coil (-) primary connection and the metal body (case) of the coil. If resistance is less then 10m ohms, replace the coil. This test may not be entirely satisfactory unless you have a megaohm tester that records 500 volts. If the tests below do not reveal the problem and, especially, if operating the engine at night may produce some bluish sparks around the coil, you may want to remove the coil and have it tested at a diagnostic center.
  2.  
  3. If the coil resistances are not as specified, replace the coil.
  4.  

If the coil tests out ok, replace the igniter and pickup coil. However, you should make sure before doing this work that there are no basic maintenance problems in the secondary circuit of the system, since it is often impossible to return electrical parts. We suggest that before you replace the igniter and pickup coil, you carefully inspect the cap and rotor for carbon tracks or cracks and disconnect the wires and measure their resistance with an ohmmeter. Resistance should be 16k ohms per 3.28 ft. (1m). Also, check for cracks in the insulation. Replace secondary parts as inspection/testing deems necessary before replacing the igniter and pickup coil.

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable and make sure the ignition switch is off. Remove any protective boots from the top of the coil, if necessary by sliding them back the coil-to-distributor wire.
  2.  
  3. Carefully pull the high tension wire out of the coil, twisting it gently as near as possible to the tower to get it started.
  4.  
  5. Note the routing and colors of the primary wires, and then remove nuts and lockwashers, retaining all parts for installation. On models equipped with plug-in connections, carefully pull the connecter from the coil assembly. Clean the primary terminals, if necessary, to ensure a clean connection. Then, loosen the through bolt or bolts which clamp the coil in place and slide the coil out of its mount. If the mounting bracket is part of the coil, remove the mounting bolts and the coil.
  6.  
  7. Install the new coil in exact reverse order, making sure the primary connections are tight. Ensure also that the coil-to-distributor wire is fully seated in the tower and that the protective boot is fully installed on the outside of the tower.
  8.  

 
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