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Home >> Subaru >> 1984 >> DL 2D Hatchback >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Ignition System - HITACHI >> Testing >> 1800 Turbo

1800 Turbo

NOTE: Use a volt-ohmmeter with a high internal impedance to check ignition system.
  1. With engine at idle speed, check voltage between terminal Black/Yellow (phase control signal) and body ground. If about 1.7 volts are present, go to step 8). If not, turn ignition switch off.
  2. Release harness connector between Knock Control Unit (KCU) and distributor. Check for continuity between terminal B (KCU ground) and body ground. If no continuity is found, ground is poor. Repair ground or replace distributor wiring harness.
  3. If 0 ohms is obtained, measure resistance between Red and Green wires (knock sensor + and -). If resistance measures 0 ohms or infinity, disconnect knock sensor leads and measure resistance at sensor. If 0 ohms or infinity is measured, replace knock sensor. If not, check wiring harness for shorted or open wires.
  4. Check continuity between Black/Yellow (phase terminal signal) and body 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 body ground. If not, replace ignitor. If continuity still present, check distributor harness for shorted or open wiring.
  6. Check 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 body ground. If continuity present, check wiring harness for shorted or open wire. If not, replace ignitor.
  8. Observe voltmeter while tapping crankcase 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, when crankcase is tapped 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 there is no continuity, check wiring harness for open wire. If continuity is present, replace ignitor.
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