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Home >> Mazda >> 1987 >> RX-7 Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - MAZDA EGI >> Testing >> Fuel Injectors >> Circuit Opening Relay (Turbo)
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Circuit Opening Relay (Turbo)

  1. If the main relay tests satisfactory, check for voltage at terminals of Circuit Opening Relay (COR) connector. Using a volt/ohmmeter set on the 20-volt scale, connect one probe to wire side of connector while connector is still plugged into the COR and the other probe to ground. See Fig 1 .
    Fig 1: View of Circuit Opening Relay
    G36021Courtesy of MAZDA MOTORS CORP.
  2. With ignition on, 12 volts should be read at the "Fc" and "B" terminals and zero volts at the "Fp", "STA" and E1 terminals. With the airflow meter measuring plate open, 12 volts should be read at the "Fp" and "B" terminals and zero volts at the "Fc", "STA" and "E1" terminals.
  3. With ignition switch in "START" position, 12 volts should be read at the "Fp", "B" and "STA" terminals and zero volts should be read at the "Fc" and "E1" terminals. Change volt/ohmmeter to the 200-ohm scale and check resistance of COR.
  4. Disconnect COR connector and check resistance between terminals on the COR. Resistance should be 15-30 ohms between terminals "STA" and "E1". Resistance should be 80-150 ohms between terminals "B" and "Fc". Resistance should be infinite between terminals "B" and "Fp". If any readings are abnormal, replace COR.