DIESEL WHITE SMOKE AT IDLE SMOKE DIAGNOSTIC INFORMATION

A CONDITION OF WHITE EXHAUST SMOKE AT IDLE WHEN THE ENGINE IS AT NORMAL OPERATING TEMPERATURE MAY BE DUE TO SLIGHTLY RETARDED INJECTION TIMING. THE FOLLOWING STEPS MUST BE ADHERED TO IN ORDER TO PROPERLY DIAGNOSE THE CONDITION AND TAKE CORRECTIVE ACTION. (1) DETERMINE IF RETARDED TIMING IS THE CAUSE OF WHITE SMOKE. A.ENGINE SHOULD HAVE A MINIMUM OF TWO HUNDRED (200) MILES. B.OPERATE ENGINE TO NORMAL TEMPERATURE (THERMOSTAT OPEN). C.CHECK ENGINE RPM AND SET IF REQUIRED TO FIVE HUNDRED AND SEVENTY- FIVE (575) RPM IN PARK (AUTO) OR NEUTRAL (MANUAL). ALSO SET FAST IDLE SPEED IF REQUIRED (FIGURE 3). D.WITH ENGINE AT PROPER IDLE SPEED, CHECK FOR EMISSION OF WHITE SMOKE. E.IF WHITE SMOKE IS EVIDENT, CONNECT A LEAD FROM THE BATTERY PLUS (+) TERMINAL TO THE COLD ADVANCE SOLENOID TERMINAL ON THE INJECTION PUMP (FIGURE 1). A NOTICEABLE CHANGE IN ENGINE SOUND WILL BE EVIDENT. ACTIVATING THE COLD ADVANCE SOLENOID INCREASES THE TIMING APPROXIMATELY THREE (3) DEGREES. F.CHECK FOR WHITE SMOKE. IF NO WHITE SMOKE IS EVIDENT OR HAS REDUCED CONSIDERABLY, A CHANGE IN TIMING SETTING IS REQUIRED. IF THE SMOKE DOES NOT DIMINISH, CHECK FOR OTHER CAUSES OF WHITE SMOKE. (ASSURE EACH CYLINDER IS FIRING-START WITH A COMPRESSION CHECK.) (2) ADJUSTMENT OF TIMING. A.THE PUMP/ENGINE FLANGES MAY OR MAY NOT HAVE A WHITE ALIGNMENT TAPE ATTACHED, WHICH WAS USED ON SOME EARLY PRODUCTION ENGINES FOR TIMING ADJUSTMENT. B.OBTAIN LOCALLY A PIECE OF WHITE TAPE AND DRAW A 1MM OFFSET LINE AS SHOWN IN FIGURE 2. C.TO CORRECT THE WHITE SMOKE PROBLEM ON THIS ENGINE, ADD A NEW TAPE WITH A 1MM OFFSET OVER THE OLD TAPE (OR BARE FLANGE(S) IF TAPE IS MISSING). CUT THE TAPE BETWEEN THE FLANGES. LOOSEN THE THREE (3) PUMP ATTACHING BOLTS AND ROTATE THE PUMP TO LINE UP THE OFFSET LINES. THE PUMP MUST BE ROTATED CLOCKWISE AS VIEWED FROM THE FRONT OF THE VEHICLE. DO NOT EXCEED 1MM OF PUMP MOVEMENT. RETIGHTEN THE THREE (3) PUMP ATTACHING NUTS TO A TORQUE OF 25-37 LB. FT. (34-50 N.M). D.NOTICE: DO NOT MAKE TIMING ADJUSTMENT WITH ENGINE RUNNING. DO NOT START ENGINE UNTIL PUMP ATTACHING NUTS ARE TORQUED SECURELY. TIMING ADJUSTMENT PROCEDURE (1) OBTAIN WHITE TAPE APPROXIMATELY ONE (1) INCH WIDE BY ONE (1) INCH LONG. (2) DRAW A CENTER LINE. (3) DRAW A PERPENDICULAR LINE DOWNWARD FROM THE CENTER LINE. (4) MEASURE FROM THIS LINE 1MM TO THE LEFT ALONG THE CENTER LINE. (5) DRAW A PERPENDICULAR LINE FROM THIS POINT IN THE OTHER DIRECTION . (6) REMOVE TAPE BACKING. (7) INSTALL ON PUMP/FLANGE INTERFACE WITH CENTER LINE ON JOINT. (8) CUT TAPE. (9) LOOSEN PUMP ATTACHING NUTS, MOVE PUMP TO ALIGN THE OFFSET LINES. (10) RETIGHTEN PUMP ATTACHING NUTS. IDLE SPEED ADJUSTMENT PROCEDURE (1) ALL IDLE SPEEDS ARE TO BE SET WITHIN +25 RPM OF SPECIFIED VALUE. (2) SET PARKING BRAKE AND BLOCK DRIVE WHEELS. (3) ENGINE MUST BE AT NORMA LOPERATING TEMPERATURE. AIR CLEANER SHOULD BE ON AND ALL ACCESSORIES SHOULD BE TURNED OFF. (4) INSTALL A KENT-MOORE J-2L925 DIESEL TACHOMETER OR EQUIVALENT PER MANUFACTURERS INSTRUCTIONS. (5) ADJUST LOW IDLE SPEED SCREW ON FUEL INJECTION PUMP TO AN ENGINE SPEED OF 600 RPM IN DRIVE (OPTIONAL 625 RPM IN NEUTRAL OR PARK) FOR AUTOMATIC TRANSMISSIONS AND 575 RPM IN NEUTRAL FOR MANUAL TRANSMISSIONS. (6) ADJUST FAST IDLE SPEED AS FOLLOWS: A.REMOVE CONNECTOR FROM FAST IDLE SOLENOID. USE AN INSULATED JUMPER WIRE FROM BATTERY POSITIVE TERMINAL TO SOLENOID TERMINAL TO ENERGIZE SOLENOID. B.OPEN THROTTLE MOMENTARILY TO INSURE THAT THE FAST IDLE SOLENOID PLUNGER IS ENERGIZED AND FULLY EXTENDED. C.ADJUST THE EXTENDED PLUNGER BY TURNING THE HEX HEAD TO AN ENGINE FAST IDLE SPEED OF 700 RPM IN NEUTRAL. D.REMOVE JUMPER WIRE AND REINSTALL CONNECTOR TO FAST IDLE SOLENOID. (7) REMOVE TACHOMETER. SERVICE INJECTION PUMP STATIC TIMING SETTING: ANY SERVICE ON THE 6.2L DIESEL ENGINE WHICH REQUIRES REPLACEMENT OF THE INJECTION PUMP REQUIRES THE STATIC TIMING MARK TO BE AT THE CORRECT SETTING. DURING THE 1982 MODEL YEAR, A CHANGE TO THE PROCEDURE FOR MARKING THE PUMP WAS MADE. INJECTION PUMPS BUILT DURING THE FIRST HALF OF THE 1982 MODEL PRIOR TO THE CHANGE, REQUIRED THE PUMP TIMING MARK TO BE OFFSET FROM THE HOUSING FLANGE MARK. TO FACILITATE THESE SETTINGS, A PIECE OF TAPE WAS USED WHICH HAD OFFSET LINES. BY LINING UP THE TAPE LINES, THE CORRECT SETTING WAS ACHIEVED. WHITE TAPE WAS USED ON LIGHT DUTY ENGINES AND YELLOW ON HEAVY DUTY. SINCE SERVICE PUMPS MAY BE OF A DIFFERENT VINTAGE THAN THE REMOVED PUMP, THE FOLLOWING MUST BE ADHERED TO FOR CORRECT TIMING SETTING WHENEVER INSTALLING A REPLACEMENT INJECTION PUMP: (1) ALL INJECTION (1) ALL INJECTION PUMPS HAVE A MODEL IDENTIFICATION PLATE WHICH IS ATTACHED TO THE PUMP HOUSING JUST BELOW THE THROTTLE LINKAGE. THE PLATE INCLUDES THE (1) MODEL NUMBER, (2) SERIAL NUMBER AND (3) THE PART NUMBER (FIGURE 1).

(2) REMOVE AND INSTALL INJECTION PUMP PER SERVICE MANUAL PROCEDURE. (3) REFER TO FIGURE 2 WHICH DISPLAYS THE LOCATION OF THE TIMING MARK WHICH ARE STAMPED INTO THE INJECTION PUMP FLANGE AND THE FRONT HOUSING. (4) REMOVE ANY TIMING TAPE THAT IS OVER THE STAMPED MARKS. (5) REFER TO THE MODEL IDENTIFICATION PLATE ON THE PUMP THAT IS BEING INSTALLED. USE THE FOLLOWING CHART TO DETERMINE THE TIMING MARK ALIGNMENT SETTING: MODEL NUMBER DB2-4090 ENGINE/RPO LIGHT DUTY (LH6) PUMP P/N 14050587 TIMING MARK OFFSET 1.5MM MODEL NUMBER DB2-4091 ENGINE/RPO HEAVY DUTY (LL4) PUMP P/N 14050588 TIMING MARK OFFSET 2.5MM MODEL NUMBER DB2-4126 ENGINE/RPO LIGHT DUTY (LH6) PUMP P/N 14050587 TIMING MARK OFFSET ALIGNED MODEL NUMBER DB2-4153 ENGINE/RPO HEAVY DUTY (LL4) PUMP P/N 14050588 TIMING MARK OFFSET ALIGNED (6) IF THE PUMP IS A DB2-4090 OR 4091 ALWAYS HAVE THE MARK ON THE PUMP TOWARDS THE LEFT SIDE (DRIVER'S) OF THE MARK ON THE HOUSING. THIS IS THE ADVANCE DIRECTION. (7) NOTICE: IF AN INJECTION PUMP IS TO BE REMOVED AND THEN REINSTALLED, IT SHOULD BE FIRST PAINT MARKED AT THE PUMP TO HOUSING FLANGE TO ALLOW REINSTALLATION AT THE ORIGINAL SETTING. (8) CAUTION - DO NOT MAKE TIMING ADJUSTMENT WITH THE ENGINE RUNNING. DO NOT START ENGINE UNTIL PUMP ATTACHING NUTS ARE TORQUED SECURELY. USE APPLICABLE LABOR OPERATION AND TIME.

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