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Home >> Plymouth >> 1981 >> Horizon Base, 1.7L Eng VIN A, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Hall Effect Electronic Spark Control System >> Testing >> Poor Performance Tests >> Computer Spark Advance
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Computer Spark Advance

  1. Warm engine to normal operating temperature. Disconnect carburetor switch or un-ground it. Be sure coolant temperature sensor is working properly and is connected.
  2. Remove and plug vacuum hose at vacuum transducer. Connect an auxiliary vacuum supply to vacuum transducer (16 in. Hg). Increase engine speed to 2000 RPM and wait 1 minute before checking specifications. Advance specifications are in addition to basic advance.
    NOTE: On systems with an accumulator, the specified time must be reached with the carburetor switch ungrounded before checking for specified spark advance schedule.
  3. If computer fails to obtain settings shown on emission control label, replace computer.
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