IDLE SURGE ON COLD START (NEW FLASH PROM). Oldsmobile Cutlass Ciera 1996

REVISION:10/25/96

THIS BULLETIN IS BEING REVISED TO CORRECT LABOR OP UNDER WARRANTY INFORMATION. PLEASE DISCARD BULLETIN 67-65-31 (SECTION 6E-ENGINE FUEL AND EMISSION). ----------------------------------------------------------------------

SUBJECT: IDLE SURGE ON COLD START (NEW FLASH PROM)

MODELS: 1996 BUICK CENTURY 1996 OLDSMOBILE CUTLASS CIERA WITH 3100 V6 ENGINE (VIN M--RPO L82)

CONDITION:

SOME OWNERS MAY COMMENT THAT THE ENGINE IDLE WILL FLUCTUATE ON THE INITIAL COLD START OF THE DAY PRIOR TO THE VEHICLE BEING SHIFTED OUT OF PARK POSITION. THIS TYPICALLY OCCURS AT THE POINT THE EMISSION CONTROL SYSTEM GOES FROM "OPEN" LOOP TO "CLOSED LOOP" STATUS. THIS CONDITION IS MOST NOTICEABLE IN WARMER AMBIENT TEMPERATURES.

CAUSE:

THE IDLE SURGE IS CAUSED BY THE DIFFERENCE IN FUELING BETWEEN "OPEN" AND "CLOSED" LOOP OPERATION.

CORRECTION:

A NEW FLASH PROM HAS BEEN RELEASED TO CORRECT THIS CONDITION. THE FOLLOWING CHANGES HAVE BEEN INCORPORATED IN THE NEW FLASH PROM:

1. TIME DELAY INCREASE TO CLOSED LOOP. 2. SMALLER FUELING CORRECTIONS IN THE TRANSITION FROM OPEN TO CLOSED LOOP.

THESE CHANGES SERVE TO TAKE SMALLER FUELING CORRECTIONS FROM OPEN TO CLOSED LOOP TO AVOID IDLE FLUCTUATIONS.

PARTS INFORMATION THE NEW FLASH PROM WILL BE AVAILABLE FROM THE GM SERVICE TECHNOLOGY GROUP STARTING WITH CD #16.

IMPORTANT: DO NOT ATTEMPT TO ORDER THE FLASH PROMS FROM GMSPO. THE FLASH PROMS ARE PROGRAMMED INTO THE PCM (POWERTRAIN CONTROL MODULE) VIA A TECHLINE TOOL DEVICE.

EMISSION CALIBRATION NUMBER

NATIONWIDE 16251204

CANADIAN 16251214

WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR CODE: J6355 PROM REPROGRAMMING, ON CAR LABOR CODE: J6352 PROM REPROGRAMMING, OFF CAR USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 0 ATTACHMENTS: 0

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