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1978-79 RX7 (Man. Trans.)

  1. Disconnect vacuum sensing tubes from vacuum control valve and vacuum pipe. Disconnect vacuum control valve. Blow through vacuum sensing tube. Air should pass through valve and come out the side fitting (vacuum pipe).
  2. Apply battery power to vacuum control valve at one valve electrical terminal and ground the other. See Fig 1. Again, blow through vacuum sensing tube. Air should come out of air filter. If valve does not respond in this manner, replace it.
Fig 1: Vacuum Control Valve Test
G09310040Courtesy of MAZDA MOTORS CORP.