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1800 Turbo

NOTE: Use a volt-ohmmeter with a high internal impedance to check ignition system.
  1. With engine at idle speed, check voltage at Black/Yellow wire (check terminal) of Knock Control Unit (KCU). If about 1.7 volts are present, go to step 8). If not, turn ignition switch "OFF".
  2. Disconnect the KCU to distributor harness connector. Check for continuity between Black wire and ground. If no continuity is found, check for bad ground or wiring harness.
  3. Measure resistance between Green and Red wires (knock sensor). If either 0 ohms or infinity is measured, disconnect knock sensor and measure resistance. If 0 ohms or infinity is measured, replace knock sensor. If not, check wiring harness for shorted or open wires.
  4. Check for continuity between Black/Yellow wire and ground. If not, go to step 6). If continuity is found, disconnect Black/Yellow terminal in distributor.
  5. Check for continuity between Black/Yellow wire and ground. If not, replace ignitor. If continuity still present, check distributor harness for shorted or open wiring.
  6. Check for continuity between Black/Red wire and ground. If continuity is present, go to step 7). If not, check continuity between Blue/Red terminal at distributor and KCU connector. If not, check wiring harness for open wire. If continuity is present, replace KCU.
  7. Disconnect Black/Red wire in distributor. Check for continuity between Black/Red wire at KCU connector and ground. If continuity present, check wiring harness for shorted or open wire. If not, replace ignitor.
  8. Observe voltmeter while hitting engine 10 times or more with a small hammer. If voltmeter increases to about 4.5 volts, go to step 9). If not, disconnect one wire at knock sensor. If voltmeter changes to about 4.5 volts, replace KCU. If not, replace knock sensor.
  9. Connect a timing light to engine. Check to see if timing retards from 15°-5° BTDC, after engine is hit with a small hammer. If yes, go to step 10). If not, turn ignition switch "OFF". Check for continuity between Black/Yellow wire in distributor and KCU harness connector. If continuity is present, replace the ignitor. If not, check wiring harness for open wire.
  10. Connect a voltmeter to Black/Yellow wire (check terminal). Observe voltmeter while hitting engine with small hammer. When voltmeter reads about 4.5 volts, increase engine speed. Voltmeter should drop to about 1.7 volts when engine is over 4850 RPM. If so, knock sensor system is okay. If not, turn ignition switch "OFF".
  11. Disconnect the KCU wiring harness. Start engine. With engine at idle speed, measure voltage between the Black/Red wire from the distributor and ground. If about .5 volts are present, replace the KCU. If 0 volts are present, turn ignition switch "OFF".
  12. Check continuity between the Black/Yellow wire from the distributor and ground. If continuity is present, go to step 7). If not, check continuity between Black/Red terminal in distributor and KCU connector terminal. If no continuity, check wiring harness for open wire. If continuity is present, replace ignitor.
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