Toyota Celica/Supra 1971-1985 Repair Guide

Ignition Coil

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REMOVAL & INSTALLATION



The ignition coil is mounted on the fender well. The later models, beginning around 1983, will have an igniter attached to the top of the coil.

  1. Disconnect the negative battery cable.
  2.  
  3. Tag and disconnect the wires attached to the unit.
  4.  
  5. Remove the coil bracket mounting bolts.
  6.  
  7. Slide the coil out of the bracket.
  8.  

To install:
  1. Slide the new coil into the mounting bracket.
  2.  
  3. Attach and secure the tagged wires to the unit.
  4.  
  5. Tighten the mounting bracket bolts.
  6.  
  7. Connect the negative battery cable.
  8.  

PRIMARY RESISTANCE CHECK



See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Checking coil primary resistance with an ohmmeter

In order to check the coil primary resistance, you must first disconnect all wires from the ignition coil terminals. Using an ohmmeter, check the resistance between the positive (15) and the negative (1) terminals on the coil. The resistance should be:



18R-C-1.3-1.7 ohms
 
20R (1975-79)-1.3-1.7 ohms
 
20R (1980)-0.5-0.6 ohms
 
22R (1981)-0.8-1.0 ohms
 
22R and 22R-EC (1982-85 US models)-0.8-1.1 ohms
 
22R and 22R-EC (1982-85 Canadian models)-0.4-0.5 ohms
 
4M-E-0.5-0.7 ohms
 
5M-E-0.5-0.6 ohms
 
5M-GE-0.4-0.5 ohms
 

If the resistance is not within these tolerances, the coil will require replacement.

SECONDARY RESISTANCE CHECK



See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: Checking coil secondary resistance with an ohmmeter

In order to check the coil secondary resistance, you must first disconnect all wires from the ignition coil terminals. Using an ohmmeter, check the resistance between the positive (15) terminal and the coil wire (4) terminal. The resistance should be:



18R-C and 20R (1970-79)-6,500-0,500 ohms
 
20R (1980)-11,500-15,500 ohms
 
22R (1981)-11,500-15,500 ohms
 
22R (1982-83)-8,500-11,500 ohms
 
22R-EC (1983-84)-10,700-14,500 ohms
 
22R-EC (1985)-11,400-15,600 ohms
 
4M-E-11,500-15,500 ohms
 
5M-E-11,500-15,500 ohms
 
5M-GE-8,500-11,500 ohms
 

If the resistance is not within these tolerances, the coil will require replacement.

 
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