GM Grand Am/Achieva/Calais/Skylark/Somerset 1985-98

Ignition Coils

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TESTING



  1. Turn the ignition to the OFF position.
  2.  
  3. Disconnect one spark plug lead at a time.
  4.  
  5. Connect a spark tester to the spark plug lead. Then perform the secondary spark test.
  6.  
  7. Perform this test at all spark plug boots. If the spark is present, then the ignition coil and the DIS ignition module are functioning properly.
  8.  
  9. If the spark is not present, then turn the ignition OFF , ground the opposite plug lead of the effective coil at the spark plug.
  10.  
  11. The spark should occur when the engine is cranked.
  12.  
  13. If spark does occur, check the condition of the spark plug leads and replace as necessary. Then repeat the test.
  14.  
  15. If spark does not occur, check the resistance of the each plug wire of the coil which did not fire at the spark test. Wire resistance should be less than 30,000 ohms each and the wires should not be grounded.
  16.  
  17. If the wires are defective then they should be replaced.
  18.  
  19. If the wires are functioning properly, unfasten the coil retaining nuts and remove the coil. Inspect the coils for signs of carbon tracking. If there is no carbon tracking replace the ignition coil. Also check for faulty plug wire connections and wire nipples for wire tracking. If carbon tracking is present, replace the old coil with a know good coil and perform the secondary spark test again.
  20.  
  21. If the spark now occurs the problem has been repaired and the original ignition coil was faulty. If spark does not occur, replace the DIS module.
  22.  

REMOVAL & INSTALLATION



See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  
  3. Tag and detach the spark plug wires.
  4.  
  5. Unfasten the coil retaining nuts.
  6.  
  7. Separate, then remove the coil(s) from the module.
  8.  

To install:
  1. Fit the coil(s) to the module, then securing using the retaining nuts. Tighten the nuts to 40 inch lbs. (4 Nm).
  2.  
  3. Attach the spark plug wires as tagged during removal.
  4.  
  5. Connect the negative battery cable.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: View of the ignition coils, module and crankshaft sensor-1987-91 2.5L engine



Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the DIS assembly and related components-1987-91 2.5L engine

 
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