Ignition Control Module: Testing and Inspection

1. Start and run engine to operating temperature.
2. Hook up timing light and tachometer.
3. Check ignition timing. If incorrect, adjust to specifications. If correct, check advance operation. If advance is operating properly, set engine speed to 1000 RPM. If advance is not operating properly, advance mechanism is defective.
4. Using a soft faced mallet, gently tap injection mixer mounting stud (located at left front of mixer body). After tapping mixer mounting stud, ignition timing should be retarded. If timing is retarded, measure voltage between terminal 6 on 1985 models or terminal 7 on 1986 - 88 models of ESC igniter and ground. If voltage obtained measures 1 volt or less, pressure sensor is defective or wire harness is short circuited. If voltage reading obtained exceeds specified amount, ESC igniter is defective.
5. If after tapping mixer mounting stud and timing is not retarded, disconnect electrical connector from pressure sensor. After disconnecting electrical connector, timing should be retarded. If timing is retarded, check shielding wire of detonation sensor signal circuit for continuity. If there is continuity, detonation sensor or ESC igniter is defective. If no continuity, wire harness is defective. If timing is not retarded, gently tap mixer mounting stud. If timing is still not retarded, ESC igniter or detonation sensor is defective. If timing is now retarded, disconnect detonation sensor electrical connector. After disconnecting electrical connector, 8° retard should be obtained. If not, ESC igniter is defective. If 8° retard is obtained, ESC igniter is satisfactory.
6. Reduce engine speed to idle speed and stop engine.
7. Connect pressure sensor and detonation sensor electrical connectors.