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Home >> Nissan-Datsun >> 1981 >> 310 Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Mixture Ratio Feedback System >> Testing >> System Check >> Notes
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System Check: Notes

  1. Visually check mixture ratio system. Check all hoses and electrical connections for proper installation.
  2. Start engine and run until it reaches normal operating temperature. Connect voltmeter positive lead to Blue/Red wire and negative lead to Black wire (210 models) or positive lead to Green/Yellow wire and negative lead to Black wire (310 models) at function check connector.
    NOTE: Function check connector is located under left side of instrument panel.
  3. Coolant temperature switch functions properly if voltmeter reads 12 volts when coolant temperature is below 95°F (35°C), or if voltmeter reads 0 volts when coolant temperature is above 95°F (35°C).
  4. Disconnect mixture ratio control solenoid valve connector. With engine running, apply 12 volts to valve. If valve is operating properly, a clicking sound can be heard from valve and engine speed will change. If not, replace mixture ratio control solenoid valve.
  5. Lift rear of car high enough so that wheels turn freely, support rear of car with safety stands, and block front wheels. Start engine and place transmission in high gear. Connect voltmeter positive lead to Blue/Red wire and negative lead to Black wire (210 models) or positive lead to Green/Yellow wire and negative lead to Black wire (310 models) at function check connector.
  6. Speed detecting switch is operating correctly if voltmeter reads 12 volts when vehicle speed is above 40 MPH, or if voltmeter reads 0 volts below 40 MPH.
    CAUTION: Be sure that vehicle speed does not exceed 55 MPH.
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