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Deceleration Control System: Adjustment

NOTE: This adjustment is to be performed when replacing components found defective during "Testing" sequence.
  1. With engine at normal operating temperature, set transmission in neutral (all transmissions).
  2. Adjust carburetor to specified curb idle speed. On Auto. Trans. vehicles, this will be set to 150 RPM higher than specified curb idle speed (which is set with transmission in "DRIVE"), although transmission will remain in neutral. This is to keep minimum load on engine.
  3. Disconnect system vacuum hose from throttle positioner diaphragm, and plug hose. Using "slave" hose, connect manifold vacuum source to diaphragm.
  4. Allow one minute for engine speed to stabilize. If engine speed is within specifications, modulator is properly set. Go to step 7).
  5. If RPM was not within specification, adjust throttle positioner by loosening lock nut and turning it until speed is within limits. Retighten lock nut.
    NOTE: On Carter 1-barrel carburetors, avoid damage to diaphragm by holding diaphragm shaft with 1/4" wrench while turning adjusting screw with 3/8" wrench.
  6. Detach manifold vacuum hose from positioner diaphragm, and allow engine to return to idle condition. Repeat procedure from step 2) as required until proper function occurs.
  7. Disconnect manifold vacuum hose from positioner diaphragm and allow engine to return to normal idle. Remove plug from original hose and reconnect it to throttle positioner fitting.
  8. On Auto. Trans. vehicles, reset idle to specifications with transmission in "DRIVE".
  9. On all vehicles, stop engine. Install air cleaner assembly.
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