GM Astro/Safari 1985-1996 Repair Guide

Ignition Coil

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See Figures 1, 2 and 3



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Fig. Fig. 1: Ignition component mounting points on early 4-cylinder engines



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Fig. Fig. 2: Ignition component mounting points on late 4-cylinder engines



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Fig. Fig. 3: Ignition component mounting points on HVS equipped 6-cylinder engines

The ignition coil on the 2.5L engine, is located on the right rear side of the engine; on the 4.3L (1985) engine, it is located in the top of the distributor cap; on the 1986 and later 4.3L engine, it is located on intake manifold to the right side of the engine.

TESTING



See Figures 4 and 5

The following procedures require the use of an ohmmeter.



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Fig. Fig. 4: Ignition coil testing points-HEI/EST coil



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Fig. Fig. 5: Ignition coil testing points-HVS coil

2.5L Engine

For this procedure, the ignition coil may be removed from the engine or simply remove the electrical connectors and test it on the engine.

  1. Using an ohmmeter (on the high scale), connect the probes between the primary (low voltage) terminal and coil ground; the reading should be very high or infinity, if not, replace the coil.
  2.  
  3. Using an ohmmeter (on the low scale), connect the probes between both primary (low voltage) terminals; the reading should be very low or zero, if not, replace the coil.
  4.  
  5. Using an ohmmeter (on the high scale), connect the probes between a primary (low voltage) terminal and the secondary (high voltage) terminal; the reading should be high (not infinite), if not, replace the coil.
  6.  

4.3L Engine
CARBURETED

To test the ignition coil, the distributor cap must be removed from the distributor.

  1. Remove the electrical connector from the distributor cap and the distributor cap from the distributor. Place the distributor cap on a workbench in the inverted position.
  2.  
  3. Using an ohmmeter (on the low scale), connect the probes between the primary (low voltage) terminals; the reading should be low or nearly zero, if not, replace the coil.
  4.  
  5. Using an ohmmeter (on the high scale), connect the probes between a primary (low voltage) terminal and the secondary (center terminal or high voltage) terminal; the reading should be high (not infinite), if not, replace the coil.
  6.  

FUEL INJECTED

For this procedure, the ignition coil may be removed from the engine or simply remove the electrical connectors and test it on the engine.

  1. Using an ohmmeter (on the high scale), connect the probes between the primary (low voltage) terminal and coil ground; the reading should be very high or infinity, if not, replace the coil.
  2.  
  3. Using an ohmmeter (on the low scale), connect the probes between both primary (low voltage) terminals; the reading should be very low or zero, if not, replace the coil.
  4.  
  5. Using an ohmmeter (on the high scale), connect the probes between a primary (low voltage) terminal and the secondary (high voltage) terminal; the reading should be high (not infinite), if not, replace the coil.
  6.  

REMOVAL & INSTALLATION



See Figures 6, 7, 8, 9 and 10



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Fig. Fig. 6: Terminal identification for coil and distributor



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Fig. Fig. 7: Always pull on the boot to remove the ignition wires, never the wire itself



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Fig. Fig. 8: Depress the tabs to release the connector from the coil



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Fig. Fig. 9: The coil will be mounted to the manifold directly or to a bracket which is bolted to the manifold



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Fig. Fig. 10: Check the coil for cracks and other signs of damage before installation

2.5L Engine

The ignition coil is located near the cylinder head at the right rear side of the engine. The coil is located under the intake manifold on the later model 2.5L engines.

  1. Disconnect the negative battery terminal and remove the console cover.
  2.  
  3. At the ignition coil, disconnect the ignition switch-to-coil wire and the distributor-to-coil wires.
  4.  
  5. Remove the coil-to-engine nuts/bolts and the coil from the engine.
  6.  
  7. If necessary, test or replace the ignition coil.
  8.  
  9. To install, mount the coil onto the engine, torque the nuts to 20 ft. lbs. (27 Nm) and reconnect all coil and battery connectors.
  10.  

4.3L Engine

CARBURETED

The ignition coil is located in the top of the distributor which is positioned at the top rear of the engine.

  1. Disconnect the negative battery terminal and remove the console cover from inside the vehicle.
  2.  
  3. At the ignition coil, on top of the distributor, disconnect the electrical connector and remove the spark plug wire retainer.
  4.  
  5. Remove the coil cover-to-distributor cap screws and the cover. Mark the coil terminals for installation purposes.
  6.  
  7. Remove the coil-to-distributor cap screws and the coil from the cap.
  8.  
  9. If necessary, test or replace the coil.
  10.  
  11. To install, position the high tension button and seal and coil into the cap.
  12.  
  13. Insert the terminals into the proper cap locations. Install the coil cover and spark plug retainer. Reconnect the coil and battery terminals.
  14.  

FUEL INJECTED

The ignition coil is located, on top of the intake manifold, next to the distributor or midway along the valve cover.

  1. Disconnect the negative battery terminal and remove the console cover inside the vehicle.
  2.  
  3. Disconnect the engine control switch and tachometer terminals from the ignition coil.
  4.  
  5. Disconnect the ignition coil-to-distributor lead wire from the coil.
  6.  
  7. Remove the coil bracket/coil assembly-to-engine bracket nuts and the assembly from the engine.
  8.  
  9. If necessary, test or replace the coil.
  10.  
  11. If necessary to remove the coil from the bracket, perform the following procedures:
    1. Using a drill, drill out the coil-to-bracket rivets.
    2.  
    3. Using a center punch, drive the rivets from the coil-to-bracket assembly.
    4.  
    5. Remove the coil from the coil bracket.
    6.  

  12.  

To install:
  1. Install the coil on the bracket with two screws, position the coil on the engine and torque the nuts to 20 ft. lbs. (27 Nm).
  2.  
  3. Connect the coil connectors and negative battery cable. Install the console cover.
  4.  

 
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