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Ignition Control System Tests

  1. Check Ignition Control System  - Turn ignition off and connect ECU connectors. Disconnect fuel injector connector. Using a timing light, verify ignition spark when cranking engine. If ignition spark is present, see LOYALE under FUEL PUMP CIRCUIT TEST. If ignition spark is not present, go to next step.
  2. Check Crankshaft Position Sensor Harness I  - Disconnect crankshaft position sensor connector at distributor. Turn ignition on. Ensure there is more than 10 volts between crankshaft position sensor connector Green/Black wire and ground. If voltage measured is greater than 10 volts, go to next step. If voltage measured is less than 10 volts, verify more than 10 volts at ECU terminal No. 19 (Green/Black wire). If more than 10 volts are present, repair harness or connectors as necessary. If more than 10 volts are not present, replace ECU.
  3. Check Crankshaft Position Sensor Harness II  - With ignition turned on, verify more than 4 volts between crankshaft position sensor connector Black/White wire and ground, and Green/Yellow wire and ground. If more than 4 volts are present, connect crankshaft position sensor connector and go to next step. If voltage is less than 4 volts, verify more than 4 volts between ECU connector terminals No. 21 (Black/White wire) and ground, and No. 20 (Green/Yellow wire) and ground. If voltage is more than 4 volts, repair harness or connectors as necessary. If voltage is less than 4 volts, replace ECU.
  4. Check Crankshaft Position Sensor Signal  - Disconnect 2-pin ignition coil power transistor connector. Turn ignition on. Slowly turn crankshaft without using starter. Ensure there is voltage change repeats from zero to 5 volts between ECU position signal terminal No. 21 (Black/White wire) and ground. If voltage does not change, replace crankshaft position sensor. If voltage changes, verify voltage change repeats from zero to 5 volts between ECU reference signal terminal No. 20 (Green/Yellow wire) and ground. If voltage does not change, replace crankshaft position sensor. If voltage changes, connect 2-pin ignition coil power transistor connector and go to next step.
  5. Check Ignition Coil Power Transistor  - Connect injector connector and turn ignition on. Ensure there is more than 10 volts between ignition coil power transistor 2-pin terminal White/Yellow wire and ground. If less than 10 volts is present, repair harness or connectors as necessary. If voltage is more than 10 volts, verify more than 10 volts between ignition coil negative terminal and ground. If voltage is less than 10 volts, replace ignition coil. If voltage is more than 10 volts, disconnect 2-pin ignition coil power transistor connector. Monitor voltage change between 2-pin signal terminal White/Yellow wire at ignition coil power transistor and ground while cranking engine. If voltage changes while engine is cranking, replace ignition coil. If voltage does not change while engine is cranking, repair harness or connectors as necessary.
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