WHITE SMOKE ROUGH IDLE POOR THROTTLE RESPONSE. GMC Truck GMC P52 RV/Van Chassis 1997

SUBJECT: WHITE SMOKE, ROUGH IDLE, POOR THROTTLE RESPONSE ON COLD START (REFLASH WITH NEW CALIBRATION)

MODELS: 1997 CHEVROLET AND GMC C/K AND P MODELS 1997 HUMMER (AM GENERAL) 1997 REUMECH WITH 6.5L DIESEL ENGINES (VINS S, F--RPOS L56, L65, L65-CMT) BUILT PRIOR TO JANUARY 13, 1997 AND THE FOLLOWING VIN BREAKPOINTS.

VIN BREAKPOINTS: PONTIAC EAST CHEV (L56) 1GCEK19S2VE194731 CHEV (L65) 1GCGK29F8VE193553 GMC (L56) 1GTFC29S3VE536047 GMC (L65) 1GTHC39F6VE532480 FLINT CHEV (L65) 1GCHC33F7VF022349 GMC (L65) 1GTHC39F6VF022642 FORT WAYNE CHEV (L65) 1GCHK34F5VZ175523 GMC (L65) 1GTGK24F8VZ524244 JANESVILLE (1) CHEV (L65) 1GBKC34F7VJ105768 JANESVILLE GMC (L65) 1GKJK16F2VJ725146 JANESVILLE (2) CHEV (L65) XXXXXXXXXXX356858 JANESVILLE GMC (L65) XXXXXXXXXXX510527 SILAO CHEV (L65) 3GNEK18S6VG133867 GMC (L65) 3GKGK26F5VG511436

THIS BULLETIN IS BEING REVISED TO CHANGE SUBJECT/CONDITION INFORMATION.

IMPORTANT: ON P MODELS, INSTEAD OF VIN BREAKPOINTS, PLEASE CHECK CURRENT VEHICLE CALIBRATION VERSUS THE AVAILABLE CALIBRATION. UPGRADE VEHICLE CALIBRATION IF A NEW CALIBRATION IS AVAILABLE.

CONDITION:

SOME OWNERS MAY EXPERIENCE WHITE SMOKE, A ROUGH IDLE, AND POOR THROTTLE RESPONSE ON INITIAL COLD START. THE CONDITION MAY LAST UP TO SEVERAL MINUTES AFTER INITIAL START UP.

IT IS POSSIBLE THAT DTC P1216 OR P1217 MAY BE SET DURING THIS CONDITION, HOWEVER OFTEN NO DTC'S WILL SET. IF TECH 2 FAILURE RECORDS DATA ARE AVAILABLE, OR IF THE TECHNICIAN CAN MONITOR THE VEHICLE WHEN THE CONDITION OCCURS, THE DATA MAY INDICATE THAT THE DESIRED IDLE SPEED AND THE ACTUAL IDLE SPEED DO NOT CORRESPOND, THE ACTUAL WILL BE LOWER THAN DESIRED. ALSO, THE FUEL SOLENOID CLOSURE TIME MAY EXCEED 3MS AT IDLE, AND THE FUEL RATE IS FIXED AT 10MM. THE CONDITION WILL NO LONGER EXIST WHEN THE ENGINE WARMS SUFFICIENTLY, NORMALLY AFTER A FEW MINUTES.

DO NOT REPLACE THE FUEL INJECTION PUMP FOR THIS CONDITION.

CAUSE:

ALWAYS PERFORM NORMAL DIAGNOSTICS INCLUDING AN ON BOARD DIAGNOSTICS (OBD) SYSTEM CHECK PRIOR TO MAKING ANY REPAIRS. THE OBD SYSTEM CHECK IS LISTED IN THE ENGINE CONTROLS SECTION OF THE APPROPRIATE TRUCK SERVICE MANUAL. DIAGNOSTICS SHOULD ALSO INCLUDE CHECKING FOR AIR OR WATER IN THE FUEL, CETANE RATING, AND GLOW PLUG OPERATION. IF THIS DOES NOT LEAD TO PROBLEM RESOLUTION, THE VEHICLE IS MOST LIKELY IN THE START LOGIC MODE OF OPERATION. WHEN THE VEHICLE IS OPERATING IN THIS MODE, NORMAL ENGINE OPERATION AND THROTTLE RESPONSE ARE NOT POSSIBLE.

CORRECTION:

CHECK THE CALIBRATION IDENTIFICATION NUMBER USING A TECH 2 SCAN TOOL, THEN CHECK THE TECHLINE TERMINAL FOR AN UPDATED CALIBRATION NUMBER. REFLASH WITH THE UPDATED CALIBRATION IF THE CURRENT VEHICLE CALIBRATION IS NOT THE NEWEST ONE LISTED IN YOUR TERMINAL. REFER TO THE APPROPRIATE SERVICE MANUAL OR TECHLINE USERS GUIDE FOR DETAILED INSTRUCTIONS ON THE REPROGRAMMING PROCEDURE.

WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OPERATION - J6355 DESCRIPTION - REPROGRAMMING PROM LABOR TIME - USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 0 ATTACHMENTS: 0

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.