The first check of the primary ignition coil is to verify that there is battery voltage at the BATT terminal on the coil. A DVOM is recommended to test for voltage. Turn the ignition switch to the RUN position and connect the negative lead of the DVOM to a ground or the negative post/cable clamp on the battery. Connect the other lead of the DVOM to the BATT terminal on the coil. The voltage measured should be within 1 volt of the battery voltage as measure across the posts of the battery.
See Figure 1
After verifying there is battery voltage present, the next check is to verify the operation of the coil primary ground which is received at the coil from the ICM (Ignition Control Module). This check is accomplished using a test lamp and connecting the lead of the test lamp to the ground or the battery negative post/cable clamp. Connect the test lamp to the ground side of the coil (the connection opposite the BATT terminal on the coil on the other side of the coil tower) and crank the engine. The light should blink on and off repeatedly as long as the engine cranks or runs. If the light does not blink the problem is either in the ICM or the PIP signal generated by the sensor inside the distributor.
See Figures 2 and 3
The final check of the primary coil is to check the resistance of the coil. This is accomplished by using a DVOM and probing the BATT terminal and the coil ground terminal. Measure the resistance between the two terminals. If the resistance is between 0.3 and 1.0 ohm, the primary ignition coil is within specifications. If the reading differs from this specification, replace the coil and retest.
See Figure 4
The coil secondary resistance is the final check of the ignition coil. Use a DVOM to measure the resistance between the BATT terminal to the high voltage terminal of the ignition coil. If the reading is between 6,500-11,500 ohms, the ignition coil is OK. If the reading is less than 6,500 or more than 11,500 ohms, replace the ignition coil. If the secondary windings are within specifications and the primary circuit also tests within specifications, inspect and test the spark plug wires and the spark plugs, refer to General Information & Maintenance .
REMOVAL & INSTALLATION
See Figure 5
- Pulling on the connector boot, detach the high tension lead at the coil.
See Figure 6
- Disconnect the wiring at the ignition coil.
- Remove the ignition coil-to-bracket attaching screws, then remove the coil.
See Figures 7 and 8
- Install the coil, tightening the screws to 25-35 inch lbs. (3-4 Nm).
- Connect the ignition coil wiring harness and the high tension lead.