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Minimum Idle - Deville/sixty-Special Buick Roadmaster VIII

Adjustments ~219 words
  1. Warm engine to normal operating temperature. Turn A/C and all accessories off. With ignition on and engine off, select Powertrain Control Module (PCM) override E.5.3., Idle Speed Control (ISC) motor. See appropriate G - TESTS W/ CODES article in this section.
  2. Press COOLER button on Electronic Climate Control (ECC) panel to retract ISC motor. Fuel data center should alternately display E.5.3. and 00, indicating override function has started. ISC will slowly move (about 20 seconds) to a fully retracted position.
  3. Verify throttle lever rests on minimum idle speed screw. With ISC plunger fully retracted, disconnect ISC harness. If engine stalls at this point, check throttle blades for deposits which might restrict airflow. Clean throttle body as necessary.
  4. With ISC fully retracted, plunger should not touch throttle lever. If contact is noted, adjust ISC plunger. Throttle lever must rest on minimum air screw. Ensure throttle cable, TV cable and cruise control cable are not binding. Adjust or replace cables as necessary.
  5. Using a tachometer, check minimum idle speed. Use average RPM reading. Adjust minimum idle speed if not as specified, using ISC Adjusting Wrench (J-29607). See «MINIMUM IDLE SPEED - 4.9L»(ref-19418-S18133547002001010200000) table. Ensure no vacuum leaks are present. Check TP sensor adjustment. See «THROTTLE POSITION (TP) SENSOR»(ref-19418-S31535330762001010200000) . Start engine, and check for proper idle operation.

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