Chrysler Front Wheel Drive Cars 4-CYL 1981-1995 Repair Information

Ignition Coil

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TESTING



Chrysler Ignition System

See Figure 1

The ignition coil is designed to operate without an external ballast resistor. Inspect the coil for arcing. Test the coil primary and secondary resistance.

To measure the primary resistance, connect an ohmmeter between the positive (+) and negative (-) terminals on the coil. To test the secondary resistance, connect an ohmmeter between the positive (+) coil terminal and the high voltage cable terminal on the coil. Then, measure the resistance between the positive (+) coil terminal and the coil case; the resistance for the case should exhibit infinite resistance. For 1990-95 models, the specific resistance values for coils manufactured by specific companies should be as follows:



Diamond-primary resistance at 70-80°F (21-27°C) should be 0.97-1.18 ohms and the secondary resistance should be 11,300-15,300 ohms
 
Toyodenso-primary resistance at 70-80°F (21-27°C) of 0.95-1.20 ohms and a secondary resistance of 11,300-13,300 ohms
 

For 1988-89 models, the specific resistance values for the ignition coils manufactured by specific companies should be as follows:



Chrysler Prestolite-primary resistance 1.35-1.55 ohms and a secondary resistance of 9,400-11,700 ohms
 
Chrysler Essex-primary resistance of 1.35-1.55 ohms and a secondary resistance of 9,000-12,200 ohms
 
Diamond-primary resistance of 1.35-1.55 ohms and a secondary resistance of 15,000-19,000 ohms
 

Replace any coil with a new one if it does not meet the specifications.



Click image to see an enlarged view

Fig. Fig. 1: Ignition coil cables and terminal configuration-except Premier

If the ignition coil is replaced with a new one due to a burned tower, carbon tracking, arcing at the tower, or damage to the terminal or boot on the coil end of the secondary cable, the cable must also be replaced with a new one. Arcing at the tower will carbonize the nipple which, if it is connected to a new coil, will cause the coil to fail.

If a secondary cable shows any signs of damage, the cable should be replaced with a new cable and new terminal. Carbon tracking on the old cable can cause arcing and the failure of a new coil.

TESTING FOR SPARK AT COIL

See Figure 2


WARNING
Spark plug cables may be damaged if this test is performed with more than1/4inch (6mm) clearance between the cable and an engine ground.

Remove the coil secondary cable from the distributor cap. Hold the end of the cable about 1 / 4 inch (6mm) away from a good engine ground. Crank the engine and inspect for spark at the coil secondary cable.

There must be a constant spark at the coil secondary cable. If the spark is constant, have a helper continue to crank the engine and, while slowly moving the coil secondary cable away from the ground, look for arcing at the coil tower. If arcing occurs at the tower, replace the coil with a new one. If the spark is not constant or there is no spark, proceed to the failure-to-start test.



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Fig. Fig. 2: Checking for spark at the ignition coil-except Premier

If a constant spark is present and no arcing occurs at the coil tower, the ignition system is producing the necessary high secondary voltage. However, make sure that the spark plugs are firing. Inspect the distributor rotor, cap, spark plug cables, and spark plugs-refer to Routine Maintenance . If they are in proper working order, the ignition system is not the reason why the engine will not start. Inspect the fuel system and engine for proper operation.

Eagle Ignition System

The ignition coil is designed to operate without an external ballast resistor. Inspect the coil for arcing. Test the coil primary and secondary resistance.

To measure the primary resistance, connect an ohmmeter between the positive (+) and negative (-) terminals (the terminals which are connected to the engine wiring harness) on the coil. To test the secondary resistance, connect an ohmmeter between the positive (+) coil terminal and the high voltage cable terminal on the coil. Then, measure the resistance between the positive (+) coil terminal and the coil case; the resistance for the case should exhibit infinite resistance. The primary resistance at 70-80°F (21-27°C) should be 0.5-1.0 ohms and the secondary resistance should be 4,500-5,000 ohms. Replace any coil with a new one if it does not meet the specifications.

If the ignition coil is replaced with a new one due to a burned tower, carbon tracking, arcing at the tower, or damage to the terminal or boot on the coil end of the secondary cable, the cable must also be replaced with a new one. Arcing at the tower will carbonize the nipple which, if it is connected to a new coil, will cause the coil to fail.

If a secondary cable shows any signs of damage, the cable should be replaced with a new cable and new terminal. Carbon tracking on the old cable can cause arcing and the failure of a new coil.

TESTING FOR SPARK AT COIL

WARNING
Spark plug cables may be damaged if this test is performed with more than1/4inch (6mm) clearance between the cable and an engine ground.

Remove the coil secondary cable from the distributor cap. Hold the end of the cable about 1 / 4 inch (6mm) away from a good engine ground. Crank the engine and inspect for spark at the coil secondary cable.

There must be a constant spark at the coil secondary cable. If the spark is constant, have a helper continue to crank the engine and, while slowly moving the coil secondary cable away from the ground, look for arcing at the coil tower. If arcing occurs at the tower, replace the coil with a new one.

If a constant spark is present and no arcing occurs at the coil tower, the ignition system is producing the necessary high secondary voltage. However, make sure that the spark plugs are firing. Inspect the distributor rotor, cap, spark plug cables, and spark plugs-refer to Routine Maintenance . If they are in proper working order, the ignition system is not the reason why the engine will not start. Inspect the fuel system and engine for proper operation.

REMOVAL & INSTALLATION



Except Premier Models

See Figure 3

The ignition coil is mounted on the thermostat housing on the left-hand side of the engine (radiator side).

  1. Disconnect the negative (-) battery cable from the battery.
  2.  
  3. Disconnect the distributor-to-ignition coil high tension cable from the coil.
  4.  
  5. Unplug the wiring harness connector from the coil.
  6.  
  7. Loosen and remove the coil mounting screws, then remove the coil from the vehicle.
  8.  



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Fig. Fig. 3: The ignition coil mounts to the thermostat bracket, next to the oil level dipstick-except Premier

To install:
  1. Loosely install the ignition coil onto the thermostat housing bracket. Tighten the mounting screws to 85 inch lbs. (9.5 Nm).
  2.  
  3. Attach the wiring harness connector to the coil.
  4.  
  5. Connect the distributor-to-ignition coil high tension cable to the coil.
  6.  
  7. Connect the negative battery cable to the battery.
  8.  

Premier Models

See Figure 4

Click image to see an enlarged view

Fig. Fig. 4: Ignition Control Module (ICM)/ignition coil assembly and related components-Premier

The ignition coil/ICM unit is mounted to the inner, lower fender in the engine compartment. Trace the center distributor high tension cable from the distributor cap to the ICM/ignition coil, if difficult to locate.

  1. Disconnect the negative (-) battery cable from the battery.
  2.  
  3. Unplug the Ignition Control Module (ICM)/coil electrical connectors from the coil.
  4.  
  5. Disconnect the high tension wire from the coil.
  6.  
  7. Loosen and remove the coil mounting nuts, then remove the ICM/coil from its mounting position.
  8.  

To install:
  1. Position the ICM/coil in place and secure with the mounting nuts.
  2.  
  3. Snap the electrical connectors into place on the ICM/coil.
  4.  
  5. Snap the high tension wire onto the ICM/coil.
  6.  
  7. Connect the negative (-) battery cable to the battery.
  8.  

 
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