For 1990-2009 cars

# SERVICE MANUAL UPDATE-SEC. 6E3 DRIVEABILITY AND EMISSIONS

#### SUBJECT: SMU - SECT. 6E3 - "DRIVEABILITY AND EMISSIONS", UPDATED HARMONIC BALANCER AND IGNITION MODULE

#### VEHICLES AFFECTED: 1993 "A AND N" MODELS WITH 3300 ENGINE (VIN N, RPO LG7)

This Bulletin revises Service Manual Section 6E3, "Driveability and Emissions", for the 1993 "A" and "N" carlines equipped with the 3300 (VIN N - RPO LG7) Engine. This Bulletin contains information on the Updated Harmonic Balancer and Ignition Module used for the 1993 Model Year. Refer to "System Components - Crankshaft Position Sensor - Harmonic Balancer Interrupter Rings" in the 1993 C/H Service Manual for the 3300 Engine System which is similar to the 3800 Engine System. See Page 6E3-C4-2 for a complete description of the revised system.

Please make the appropriate change to the Service Manual from the former 1X Signal to the updated 18X Signal on the following facing pages Circuit Diagram:

o 3300 (VIN N) MFI "A" Car

o Chart A-3 (1 of 2) Facing Page

o Chart A-3 (2 of 2) Facing Page

o DTC 42 Facing Page

o Chart C-4-1 Facing Page

o Chart C-4-2 Facing Page

o 3300 (VIN N) MFI "N" Car

o Chart A-3 (1 of 2) Facing Page

o Chart A-3 (2 of 2) Facing Page

o DTC 42 Facing Page

o Chart C-4-1 Facing Page

o Chart C-4-2 Facing Page

#### IMPORTANT: The 3300 (VIN N) and 3800 (VIN L) Harmonic Balancers and Ignition Modules are NOT interchangeable.

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.