CAMPAIGN: 4-CYLINDER ENGINE, CARBURETOR
GENERAL MOTORS HAS DETERMINED THAT A CARBURETOR LEAN FUEL MIXTURE MAY AFFECT ENGINE OPERATION ON CERTAIN EARLY PRODUCTION 1980 CHEVROLET CITATION MODELS. WHEN THE VEHICLES ARE DRIVEN AT A CONSTANT SPEED IN THE 35MPH RANGE, AN ENGINE SURGE CONDITION MAY BE EXPERIENCED. TO IMPROVE ENGINE OPERATION UNDER LIGHT THROTTLE CONDITIONS, DEALERS ARE TO REPLACE THE POWER PISTON AND SPRING ON AFFECTED VEHICLES, AND ADJUST ENGINE IDLE SPEED FOLLOWING THE SERVICE PROCEDURES IN THIS BULLETIN.
VEHICLES INVOLVED
INVOLVED ARE CERTAIN EARLY PRODUCTION 1980 CHEVROLET CITATION 4-CYLINDER ENGINE MODELS ASSEMBLED AT GMAD TARRYTOWN AND WILLOW RUN.
PLANT FROM THROUGH
TARRYTOWN START OF PRODUCTION 1X685AT102280 WILLOW RUN START OF PRODUCTION 1X085AW109438
VEHICLES INVOLVED IN THIS PRODUCT IMPROVEMENT CAMPAIGN WILL HAVE ONE OF THE FOLLOWING ENGINE CODES - WA,WB,XA OR XB.
INVOLVED VEHICLES HAVE BEEN IDENTIFIED BY VEHICLE IDENTIFICATION NUMBER COMPUTER LISTINGS. SOME VEHICLES WITH VEHICLE IDENTIFICATION NUMBERS WITHIN THE ABOVE LISTED RANGE OF NUMBERS WERE CORRECTED IN THE PLANTS AND WILL NOT APPEAR ON THE PRINT OUT.
DEALER CAMPAIGN RESPONSIBILITY
DEALERS ARE TO PERFORM THIS PRODUCT IMPROVEMENT CAMPAIGN ON ALL AFFECTED VEHICLES IN NEW CAR STOCK PRIOR TO VEHICLE SALE.
DEALER ACTION
DEALERS ARE TO INSPECT AND, IF NECESSARY, INSTALL THE CARBURETOR POWER PISTON SPRING REPLACEMENT KIT AS DIRECTED IN THE SERVICE PROCEDURES IN THIS BULLETIN. IN ADDITION, ON MANUAL TRANSMISSION VEHICLES, DEALERS ARE TO INSTALL A NEW TUNE-UP LABEL AS DIRECTED IN THE SERVICE PROCEDURES.
SERVICE PROCEDURES
OPEN HOOD AND OBSERVE ENGINE CODE LABEL ON TIMING COVER OR ENGINE CODE STAMPING ON PAD AT LEFT OF CYLINDER BLOCK BELOW CYLINDER HEAD. (REFER TO ILLUSTRATION BELOW).
VEHICLES WHICH REQUIRE MODIFICATIONS WILL HAVE THE FOLLOWING ENGINE CODES:
WA 4 CYLINDER 4 SPEED WITHOUT A/C WB 4 CYLINDER 4 SPEED WITH A/C XA 4 CYLINDER AUTOMATIC WITHOUT A/C XB 4 CYLINDER AUTOMATIC WITH A/C
2. IF THE ENGINE CODE IS OTHER THAN THOSE SHOWN AOBVE, MO MODIFICATION IS REQUIRED. PROCEED TO STEP 39.
3. IF THE ENGINE CODE IS ONE OF THE ABOVE, PROCEED TO STEP 4.
4. INSTALL PROTECTIVE COVERS ON FENDERS.
5. REMOVE AIR CLEANER: INCLUDES TWO (2) NUTS ON AIR CLEANER COVER, ONE (1) BOLT ON INLET PIPE AND DISCONNECTING FRESH AIR INLET, PCV INLET PIPE AND THERMAC VACUUM HOSE.
6. DISCONNECT VACUUM HOSE AND IDLE SOLENOID WIRE FROM VACUUM BREAK ASSEMBLY.
7. REMOVE UPPER AND LOWER VACUUM BREAK BRACKET TO CARBURETOR SCREWS AND REMOVE VACUUM BREAK ASSEMBLY BY LIFTING AND ROTATING TO DISCONNECT LINKAGE (FIGURE 1).
8. REMOVE CLIP FROM INTERMEDIATE CHOKE ROD AT CHOKE LEVER, DISCONNECT ROD AND REMOVE ROD BUSHING (FIGURE 2).
NOTICE: DO NOT REUSE CHOKE ROD CLIP. A NEW CLIP AND BUSHING IS INCLUDED IN THE MODIFICATION PACKAGE.
9. REMOVE PUMP LEVER TO AIR HORN SCREW AND SPACER WASHER AND ROTATE LEVER TO DISCONNECT LINKAGE (FIGURES 3 AND 4).
NOTICE: DO NOT REUSE THE SPACER WASHER. A NEW PUMP SCREW SPACER WASHER IS INCLUDED IN THE MODIFICATION PACKAGE.
10. IF THE VEHICLE IS EQUIPPED WITH AIR CONDITIONING (A/C), REMOVE THE HOT IDLE COMPENSATOR AND SEAL FROM THE AIR HORN AND DISCARD THE SEAL (FIGURE 5).
11. REMOVE THE TWO (2) VENT SCREEN SCREWS AND REMOVE THE SCREEN ASSEMBLY.
12. DISCONNECT BOWL VENT HOSE.
13. REMOVE THE REMAINING AIR HORN TO BOWL SCREWS AND STUDS AND REMOVE AIR HORN BY LIFTING AND ROTATING TO DISCONNECT FAST IDLE CAM LINKAGE. HOLDING THE CAM IN THE HIGH STEP POSITION WILL AID REMOVAL (FIGURE 6).
14. REMOVE AND DISCARD AIR HORN TO BOWL GASKET.
15. REMOVE POWER PISTON AND METERING ROD ASSEMBLY BY PUSHING PISTON DOWN AND LETTING IT SNAP BACK AGAINST THE RETAINER (FIGURE 7).
NOTICE: IF THE RETAINER HAS NOT MOVED AFTER SEVERAL SNAPS, PLACE A SOFT BLOCK ACROSS THE BOWL TOP AND REMOVE THE PISTON WITH PLIERS USING THE BLOCK TO PROTECT THE GASKET SURFACE. EXERCISE CARE DURING REMOVAL SO THAT BOWL AND METERING ROD ARE NOT DAMAGED.
16. DISCONNECT THE METERING ROD FROM THE POWER PISTON ARM BY COMPRESSING THE SPRING AND SLIDING THE ROD FROM THE RETAINING GROOVE. DISCARD POWER PISTON (FIGURE 8).
NOTICE: PISTON AND/OR SPRING MAY POP OUT WITH SOME FORCE. USE CAUTION WHEN REMOVING.
17. REMOVE AND DISCARD POWER PISTON SPRING (STEEL: NO COLOR).
18. OBTAIN THE CARBURETOR MODIFICATION PACKAGE AND REASSEMBLE THE CARBURETOR AS FOLLOWS. CONTENTS OF PACKAGE ILLUSTRATED IN FIGURE 9.
19. INSTALL THE NEW POWER PISTON SPRING IN PISTON BORE.
20. CONNECT THE METERING ROD TO THE NEW POWER PISTON AND INSTALL THE PISTON AND ROD ASSEMBLY IN THE BOWL.
NOTICE: IT MAY BE NECESSARY TO LIGHTLY TAP THE POWER PISTON RETAINER WITH A FLAT OBJECT, FORM SIDE-TO-SIDE IN ORDER TO OBTAIN A FULL SEAT IN THE BORE.
21. PLACE THE NEW AIR HORN TO BOWL GASKET ON THE BOWL TAKING CARE TO WORK THE POWER PISTON ASSEMBLY THROUGH THE SLITS PROVIDED IN THE GASKET.
22. INSPECT FOR THE FOLLOWING:
A.FLOAT AND RETAINER ARE STILL IN PLACE. B.POWER PISTON AND METERING ROD WORK FREELY. C.PUMP SPRING IS IN THE BOTTOM OF THE PUMP BORE. D.PUMP PLUNGER IS IN PLACE IN THE AIR HRON.
23. INSTALL AIR HORN ASSEMBLY BY RECONNECTING THE CHOKE LEVER TO FAST IDLE CAM ROD AND ROTATING THE AIR HORN TO THE UPRIGHT POSITION. HOLDING THE CAM IN THE HIGH STEP POSITION WILL AID IN CONNECTING THE LINKAGE.
24. INSTALL THE AIR HORN TO BOWL SCREWS AND STUDS, INCLUDING VENT SCREEN AND SCREWS, AND LIGHTLY TORQUE.
NOTICE: THE PROVIDED METAL CARBURETOR IDENTIFICATION TAG, STAMPED "MOD", SHOULD BE PLACED UNDER SCREW NO. 6.
NOTICE: THE SCREWS ARE NOT ALL THE SAME LENGTH. BE SURE TO INSTALL THE PROPER LENGTH SCREWS IN THE CORRECT LOCATIONS. (SEE ILLUSTRATIONS FOR PROPER LOCATION AND TORQUE SEQUENCE). (FIGURE 6 AND FIGURE 10).
25. IF THE VEHICLE IS EQUIPPED WITH A/C, INSTALL THE NEW SEAL AND PLACE THE HOT IDLE COMPENSATOR ON THE AIR HORN USING THE TWO (2) RETAINING SCREWS (FIGURE 5).
26. ATTACH THE PUMP ARM TO THE THROTTLE LINK AND INSTALL THE ARM TO AIR HORN SCREW THROUGH THE AIRM USING THE NEW SPACER PROVIDED. HOLD THE PUMP SHAFT DOWN UNTIL THE SCREW IS SEATED (FIGURE 4).
27. INSTALL A NEW SLEEVE ON THE CHOKE INTERMEDIATE ROD, ROTATE THE CHOKE ARM COUNTERCLOCKWISE TO THE UPWARD POSITION AND INSTALL THE FREE END OF THE ROD WITH THE SLEEVE INTO THE CHOKE LEVER.
28. INSTALL A NEW RETAINING CLIP ON THE INTERMEDIATE CHOKE ROD SO THAT THE OUTWARD BEND OF THE CLIP IS FACING THE END OF THE ROD. THE CLIP MUST HAVE A FULL CONTACT ON THE SHAFT AND MUST NOT BE TIGHTLY SEATED AGAINST THE SPACER. (CLIP TO SPACER CLEARANCE SHOULD BE .8M (.030").
29. INSTALL VACUUM BREAK ASSEMBLY BY ROTATING TO CONNECT LINKAGE AND PLACING THE ASSEMBLY OVER THE LOCATING LUGS. (FIGURE 1).
30. INSTALL THE TWO (2) VACUUM BREAK TO CARBURETOR SCREWS.
NOTICE: THE VACUUM BREAK TO AIR HORN SCREW (TOP SCREW) HAS A TAPERED HEAD FOR LOCATION AND MUST BE TIGHTENED FIRST.
31. CONNECT VACUUM HOSE TO VACUUM BREAK CONNECTOR AND ELECTRICAL CONNECTOR TO IDLE SPEED CONTROL.
32. INSTALL BOWL VENT HOSE.
33. CHECK LINKAGE AND THROTTLE FOR FREENESS AND PROPER OPERATION.
34. PLUG THE OPEN VACUUM FITTING FOR THE AIR CLEANER AND CONNECT AN ACCURATE TACHOMETER.
35. SET THE PARKING BRAKE, START THE ENGINE AND ALLOW IT TO WARM UP.
36. SET CURB AND FAST IDLE TO THE SPECIFICATIONS ON THE EMISSIONS LABEL.
NOTICE: ON MANUAL TRANSMISSION VEHICLES, INSTALL THE NEW EMISSION LABEL PROVIDED AND ADJUST ENGINE SPEEDS TO THE REVISED SPECIFICATIONS. MANUAL TRANSMISSION VEHICLES WILL HAVE EITHER CODE FM OR FN.
CLEAN THE OLD LABEL WITH SOAPY WATER AND WIPE DRY.
NEW LABEL NO. 10009956, CODE FM, SHOULD BE APPLIED OVER OLD LABEL NO. 10009951, CODE FF, ON 4-CYLINDER, 4-SPEED WITHOUT A/C.
NEW LABE NO. 10009957, CODE FN, SHOULD BE PLACED OVER OLD LABEL NO. 10009950, CODE FD, ON 4 CYLINDER, 4-SPEED WITH A/C.
37. TURN ENGINE OFF, CONNECT COMPRESSOR ON A/C, REMOVE TACHOMETER AND PLUG FROM VACUUM FITTING.
38. INSTALL THE AIR CLEANER, REMOVE THE PROTECTIVE FENDER COVERS AND CLOSE HOOD.
REFER TO FIGURE 11 FOR 1980 CHEVROLET CITATION SPECIFICATIONS
PARTS INFORMATION
EACH INVOLVED CHEVROLET ZONE SERVICE DEPARTMENT WILL RECEIVE, NO CHARGE, ONE CARBURETOR POWER PISTON SPRING REPLACEMENT KIT FOR EACH VEHICLE ON THEIR V.I.N. LIST. THIS KIT INCLUDES ONE (1) POWER PISTON, ONE (1) POWE PISTON SPRING, TWO (2) CLIPS, ONE (1) BUSHING, ONE (1) AIR HORN GASKET, ONE (1) WASHER, ONE (1) HOT IDLE COMPENSATOR VALVE GASKET, AND ONE (1) METAL CARBURETOR IDENTIFICATION TAG. PARTS WILL BE PRO-RATED TO EACH INVOLVED DEALER BASED ON THE VEHICLE IDENTIFICATION NUMBER COMPUTER LISTINGS.
ALSO, ENCLOSED WITH THE ZONE CAMPAIGN MATERIAL IS EITHER TUNE-UP LABEL NO. 10009956, CODE FM, OR NO. 10009957, CODE FN TO BE USED ON MANUAL TRANSMISSION VEHICLES.
WARRANTY INFORMATION, FAILURE CODE, LABOR TIME ALLOWANCE, FAILED LABOR OPERATION AND CONDITION CODE
DEALER ARE TO SUBMIT EACH CAMPAIGNED VEHICLE AS A SEPARATE CASE ON THE ONE-LINE WARRANTY CLAIM FORM, GSD-970.
THE CAMPAIGN FAILURE CODE, LABOR OPERATION NUMBER AND CONDITION CODE ARE TO BE SUBMITTED EXACTLY AS SHOWN ON THE EXAMPLE GSD-970 ONE-LINE CLAIM FORM INCLUDED IN THIS CAMPAIGN BULLETIN.
DEALERS SUBMITTING WARRANTY CLAIM APPLICATIONS ON THE CHEVROLET DEALER COMMUNICATION SYSTEM ARE TO SUBMIT CAMPAIGN CLAIMS VIA THE DEALER COMMUNICATIONS TERMINAL ACCORDING TO THE CAMPAIGN CLAIM PROCEDURE DOCUMENTED IN THE CHEVROLET "DEALER COMMUNICATION SYSTEM-OPERATION GUIDE."
FIELD FAILURE LABOR TIME LABOR CONDITION CODE ALLOWANCE OPERATION CODE
1A .2 HOURS 80C03 89
DESCRIPTION: INSPECT INVOLVED VEHICLES; VEHICLE NOT INVOLVED - NO FURTHER ACTION REQUIRED.
1B .6 HOURS 80C03 89
DESCRIPTION: INSPECT AND INSTALL CARBURETOR KIT. WHEN REQUIRED, INSTALL NEW EMISSION TUNE-UP LABE (RPO M20 ONLY)
DEALERS WILL AUTOMATICALLY RECEIVE .1 HOURS DEALER ADMINISTRATIVE DETAIL ASSOCIATED WITH THIS CAMPAIGN.
DEALERS WILL AUTOMATICALLY BE CREDITED 30% OF DEALER NET WHEN PARTS ARE FURNISHED, NO CHARGE BY CHEVROLET (FAILURE CODE 1B $ .75).
ADMINISTRATIVE PROCEDURE
THE APPROPIATE CAMPAIGN HANDLING AND ADMINISTRATIVE PROCEDURE MAY BE FOUND IN THE CHEVROLET SERVICE POLICIES AND PROCEDURE MANUAL, SECTION 4, PAGES 1 AND 2, DATED OCTOBER 1978 IN YOUR DEALERSHIP.
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.
