Checking Ignition Discharge Module

Checking Signal to Ignition Coils
- Connect a voltmeter between test output for cylinder 1 on the rear of the engine and ground.
- Start engine.
- The voltmeter should read 100 - 500 mV AC.

If reading is OK:
^ Try a new ignition discharge module (IDM).

If reading is incorrect:
^ Proceed to: Checking Ignition Discharge Module Ground Terminal section below.





Check Ground Lead to Ignition Discharge Module
- Ignition OFF.
- Disconnect rear ignition discharge module connector.
- Connect an ohmmeter between ignition discharge module connector terminal 4 and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ Try a new ignition discharge module.

If reading is incorrect:
^ Proceed to: Checking Ignition Discharge Module Ground Terminal section below.





Checking Ignition Discharge Module Ground Terminal
- Ignition OFF.
- Check the rear ignition discharge module connector and ground terminal for contact resistance and oxidation and remedy.
- Connect an ohmmeter between ignition discharge module connector terminal 4 and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ The cause of the fault has been loose connections in the ignition discharge module connector or ground terminal.

If reading is incorrect:
^ Check cable between ignition discharge module and its ground terminal (31/32) for an open-circuit.