DIESEL IDLE SPEED CHANGE ROUGH ENGINE IDLE CORRECTION

SOME 6.2L DIESEL ENGINES MAY EXHIBIT A ROUGH IDLE CONDITION DUE TO ENGINE BUILD VARIATION. IF A CONDITION OF POOR IDLE IS RECEIVED, INCREASING THE IDLE SPEED 50 RPM AS DESCRIBED BELOW MAY CORRECT THE CONDITION. A MINIMUM OF 200 MILES SHOULD BE ON THE ENGINE TO HELP ELIMINATE "GREEN ENGINE" EFFECT. (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 NORMAL OPERATING TEMPERATURE. AIR CLEANER SHOULD BE ON AND ALL ACCESSORIES SHOULD BE TURNED OFF. (4) INSTALL A KENT-MOORE J-26925 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 (LIGHT DUTY LH6, UNDER 8,500 #G.V.W.), 625 RPM IN NEUTRAL OR PARK (HEAVY DUTY LL4, OVER 8,500 #G.V.W.) FOR AUTOMATIC TRANSMISSIONS AND 625 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. USE APPLICABLE LABOR OPERATION AND TIME.

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.