DRIVEABILITY CONCERNS (DIAGNOSIS AND NEW MEMCALS)

MODELS AFFECTED: 1989 REGALS WITH 3.1L V6 (VIN CODE T)

Some customers with the engine/vehicle combination listed above may comment that they have experienced one or more of the following conditions:

A cold start stall or sag,

A decel stall, or

A tip-in hesitation.

These conditions may be attributed to a number of components/interactions. In the interest of simplifying diagnosis and repair, the following procedure has been developed to reduce system sensitivity, thereby addressing a variety of potential causes simultaneously.

If a customer comment concerning an occasional engine stall or a drive hesitation is received, then complete the following procedure:

1. Perform diagnostic checks, per Section 6E3 of the Buick Chassis Service Manual and replace any defective components.

Proceed to Step #2 only if diagnostic checks uncover no cause for the customer comments.

2. Check the MEM-CAL scanner I.D. to determine if latest MEM-CAL is installed. If not, proceed to Step #3. If so, the vehicle must be reinspected for other possible causes for the problem.

3. Install a new MEM-CAL into the Engine Control Module (ECM) per instructions below. The new MEM-CAL may be ordered from GMSPO. See the attached service part number chart.

a. Pull the underhood ECM continuous power fuse or disconnect the battery and leave it disconnected for at least 10 minutes.

b. Remove current MEM-CAL and install a new service MEM-CAL.

c. Restore the battery power and place air conditioning controls (if equipped) in the "off" position.

d. Firmly apply the parking brake and block the drive wheels. Start the engine, and shift the transaxle to "drive".

e. Allow the engine to run until the engine cooling fan has cycled once, or a maximum of 10 minutes.

f. Turn the ignition key to the "off" position for at least 5 seconds.

g. Start the engine, and shift the transaxle to "drive".

h. Allow engine to run for at least 5 minutes.

WARRANTY INFORMATION

Use Labor Operation Number: T1506

Labor Time: .7 Hour

Trouble Code 92.

1989 REGAL 3.1L ENGINE MEM-CAL SELECTION CHART - SERVICE PART NUMBERS

EMISSION MEM-CAL SCANNER BROADCAST CONFIG. PART NO I.D. CODE -------- ------ ------- --------- FED 16138522 8461 ARZW

CAL 16134660 4721 ARCX

Parts are currently available from GMSPO.

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.