DECEL STALL/CRANK ON START UP (NEW IAC MOTOR)

SUBJECT: NEW IAC MOTOR - DECELERATION STALL AND/OR EXTENDED CRANK ON STARTUP

MODELS/YEARS: ALL 1988-93 W/3800 (VIN C, L, 1) AND 3300 (VIN N) ENGINES

Some of the models shown in the chart below may exhibit a deceleration stall or long crank on startup. This condition can sometimes be viewed on a scan tool as excessively high IAC counts at idle immediately after startup, or as a failure to retum to the same (or similar) IAC counts displayed at idle after several throttle maneuvers.

If this condition is experienced and currently published service diagnostic procedures indicate a malfunctioning IAC motor, it will be necessary to install a new IAC motor. Parts are currently available from GMSPO.

Year Model Engine/VIN/RPO P/N --------- -------------------- ------------------ --------

1988-90 Eighty Eight, Ninety 3800, (VIN C), LN3 17112650 Eight, Toronado 1991 Eighty Eight 3800, (VIN C), LN3 17112650 1989-93 Cutlass Ciera/Cruiser 3300, (VIN N), LG7 17112650 Calais, Achieva 1991-93 Eighty Eight, Ninety 3800, (VIN L), L27 17112649 Eight, Toronado, Silhouette 1992-93 Ninety Eight 3800 SC, (VIN 1). L67 17112649

It should be noted that two designs of IAC motors exist. The 3800 (VIN L) and the 3800 supercharged (VIN 1) use a triple slope design (see the illustration below). The 3800 (VIN C) and 3300 (VIN N) use a dual slope design. The dual slope and the triple slope designs are not interchangeable. Several part numbers for IAC motors are being phased out to standardize usage and are being replaced by cur- rent production IAC motors listed below.

WARRANTY INFORMATION: See the current Labor Time Guide.

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.