TIP-IN HESITATION PCV RESTRICTOR(ALTITUDE)

THE FOLLOWING PROCEDURES ARE TO BE USED TO CORRECT A TIP-IN HESITATION CONDITION ON FEDERAL 3.0L EQUIPPED CENTURYS IN ALTITUDE AREAS ONLY. THIS CARBURETOR RECALIBRATION PROCEDURE PROVIDES MORE LEAN LIMIT AUTHORITY TO AVOID EXCESSIVELY RICH AIR/FUEL MIXTURES AT ALTITUDE. THE PCV RESTRICTOR RESTRICTS THE BLEED OF MANIFOLD VACUUM THROUGH THE PCV SYSTEM TO ENSURE PROPER CARBURETOR OPERATION. ALL NEW GENERAL MOTORS VEHICLES ARE CERTIFIED BY THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY AS CONFORMING TO REQUIREMENTS OF THE REGULATIONS FOR THE CONTROL OF AIR POLLUTION FROM NEW MOTOR VEHICLES. THIS CERTIFICATION IS CONTINGENT ON CERTAIN ADJUSTMENTS BEING SET TO FACTORY STANDARDS. IN MOST CASES, THESE ADJUSTMENT POINTS EITHER HAVE BEEN PERMANENTLY SEALED AND/OR MAKE INACCESSIBLE TO PREVENT INDISCRIMINATE OR ROUTINE ADJUSTMENT IN THE FIELD. FOR THIS REASON, THE FACTORY PROCEDURE FOR TEMPORARILY REMOVING PLUGS, CAPS, ETC, FOR PURPOSES OF SERVICING THE PRODUCT, MUST BE STRICTLY FOLLOWED, AND WHENEVER PRACTICABLE, RETURNED TO THE ORIGINAL INTENT OF THE DESIGN. BEFORE THE FOLLOWING PROCEDURES ARE USED, THE CARBURETOR MUST BE RESET IF INTERNAL ADJUSTMENTS HAVE BEEN MADE, ACCORDING TO THE 1983 MIXTURE CONTROL SOLENOID ADJUSTMENT PROCEDURE IN THE 1983 BUICK SERVICE MANUAL. IF THE CARBURETOR HAS NOT BEEN INTERNALLY ADJUSTED, PROCEED WITH THE FOLLOWING RECALIBRATION PROCEDURES. REMOVE CARBURETOR USING PROCEDURES OUTLINED IN THE 1982 CENTURY AND SKYLARK SERVICE MANUAL. REMOVE IDLE MIXTURE NEEDLE PLUGS, USING PLUG REMOVAL PROCEDURE IN THE CENTURY AND SKYLARK SERVICE MANUAL. SEE FIGURE 1. USING TOOL J-29030, BT-7610-B, OR EQUIVALENT, TURN EACH IDLE MIXTURE NEEDLE INWARD UNTIL LIGHTLY SEATED. THEN BACK OUT EACH MIXTURE NEEDLE ONE (1) FULL TURN. RE-INSTALL CARBURETOR. D & C PCV HOSE AND INSTALL RESTRICTOR IN THE MIDDLE OF THE PCV HOSE SO THE PCV VALVE NIPPLE IS TIGHT UP AGAINST ONE SIDE OF THE RESTRICTOR AND THE STEEL PIPE IS TIGHT AGAINST THE OTHER SIDE. THIS WILL ASSURE PROPER INSTALLATION OF THE RESTRICTOR. THE PCV RESTRICTOR CAN BE OBTAINED FROM THE ZONE OFFICE OR CAN BE FABRICATED LOCALLY PER THE DRAWING. CHECK BASE TIMING - SPECIFICATION IS 15F. RE-INSTALL AIR CLEANER ASSEMBLY. DISCONNECT PURGE HOSE (BOWL VENT HOSE) AT THE CANISTER AND PLUG. PURGE HOSE MUST BE DISCONNECTED AND PLUGGED TO OBTAIN CORRECT ADJUSTMENT. USING A DWELL METER WITH ENGINE SUFFICIENTLY WARMED UP (IN CLOSED LOOP), ADJUST IDLE MIXTURE SCREWS TO OBTAIN A 15 TO 20 DEGREE DWELL. RECONNECT PURGE HOSE. AFTER ADJUSTMENTS ARE COMPLETE, SEAL THE IDLE MIXTURE SCREWS, USING SILICONE SEALANT RTV RUBBER, OR EQUIVALENT. THE SEALER IS REQUIRED TO PREVENT TAMPERING WITH THE SETTING AND TO PREVENT THE POSSIBILITY OF LOSS OF FUEL VAPORS. WARRANTY INFORMATION: LABOR OPERATION T5059 LABOR TIME .9 HRS. TROUBLE CODE 92

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.