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System Test

  1. Raise rear wheels, disconnect vacuum hose at distributor advance diaphragm and connect it to a vacuum gauge. Ensure that temperature switch is above 65°F, warm with hand or a sponge saturated with hot water if necessary. Start engine and engage transmission.
  2. Vacuum gauge should read zero until specified speed is obtained, at which point, it should register at least 6 inches Hg.
  3. If there is no vacuum, check the following: Determine that there is vacuum at carburetor vacuum port: Check for pinched, blocked, mis-routed, or disconnected vacuum hoses. Make sure that distributor vacuum control valve is open (if fitted). Disconnect one or both electrical leads at distributor modulator valve and throttle down engine. If there is no vacuum at all, replace distributor modulator valve. If there is vacuum below cut-in speeds, trouble exists in ESC system and it will be necessary to test the individual system components.
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