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Home >> Mitsubishi >> 1994 >> Eclipse Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Motors, Relays & Solenoids >> Relays >> MFI Relay (Eclipse 1.8L)

MFI Relay (Eclipse 1.8L)

  1. This step checks ignition switch supply voltage of MFI relay. Disconnect MFI relay connector. Turn ignition on. Measure voltage between terminal No. 8 of relay harness connector and vehicle ground. See Figure . If battery voltage is present, go to step 2). If battery voltage is not present, check and repair circuit between ignition switch and MFI relay.
  2. This step checks continuity of MFI relay ground circuit. Turn ignition off. Using DVOM, check continuity between MFI relay harness connector terminal No. 6 and vehicle ground. If continuity exists, go to step 3). If continuity does not exist, check and repair circuit between MFI relay and vehicle ground.
  3. This step checks battery supply voltage of MFI relay. Using DVOM, measure voltage between terminal No. 4 of relay harness connector and vehicle ground. If battery voltage is present, go to step 4). If battery voltage is not present, check and repair circuit between battery and MFI relay.
  4. This step checks continuity of circuit between MFI relay and ECM. Disconnect ECM harness connector. See ENGINE CONTROL MODULE (ECM) LOCATION  table under COMPUTERIZED ENGINE CONTROLS. Using DVOM, check continuity between MFI relay harness connector terminal No. 3 and ECM harness connector terminals No. 102 and 107. See Figure and Figure .
  5. If continuity exists, harness is okay. Go to step 6). If continuity does not exist, check and repair circuits between MFI relay harness connector and ECM.
  6. Check continuity of MFI relay. Removal of relay may assist in testing. Measure resistance between terminals No. 2 and 5 and between terminals No. 3 and 5. Resistance should be approximately 95 ohms. Measure resistance between terminals No. 6 and 7. Resistance should be approximately 35 ohms. Measure resistance between terminals No. 6 and 8. Continuity should exist in only one direction. Replace MFI relay if measurements are not as specified.
  7. Connect 12-volt power source between relay terminals No. 6 and 7. Connect positive lead to terminal No. 7. With relay energized, continuity should exist between terminals No. 1 and 4. With power source removed, continuity should not exist.
  8. Move 12-volt power source to relay terminals No. 2 and 5. Connect positive lead to terminal No. 2. With relay energized, continuity should exist between terminals No. 1 and 4. With power source removed, continuity should not exist.
  9. Move 12-volt power source to relay terminals No. 6 and 8. Connect positive lead to terminal No. 8. With relay energized, continuity should exist between terminals No. 2 and 4. With power source removed, continuity should not exist. Replace MFI relay if any measurements are not as specified.
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