For 1990-2009 cars

# 84 SERVICE MANUAL INFO. FOR COMPUTER CONTROLLED ENGINE SYS

#### Models Affected: All 1984 Computer Controlled Carbureted and Fuel Injected Vehicles

SECTION 6E "DRIVEABILITY AND EMISSIONS" INFORMATION HAS BEEN COMPLETELY REVISED FOR 1984. THE NEW FEATURES OUTLINED BELOW WILL ASSIST TECHNICIANS TO DIAGNOSE PROBLEMS MORE EASILY, SAVE TIME AND INCREASE CUSTOMER SATISFACTION.

COMPONENT AND WIRING HARNESS LOCATOR VIEWS

The "INTRODUCTION" section contains computer controlled engine system harness and component locator views.

ECM TERMINAL DATA AND VOLTAGE CHECKS

Also included in the "INTRODUCTION" section are specific computer controlled engine system circuit schematics and terminal connection information. This information provides voltages with the ignition "ON" and engine not running. Also provided are voltages for Closed Loop Operation.

SUPPORTIVE INFORMATION ON PAGE FACING TREE CHART

Section A contains the diagnostic code display procedure called the "Diagnostic Circuit Check" and the diagnostic codes tree charts. These charts provide an easy-to-follow troubleshooting path (see pg. 3).

The diagnostic charts have a facing page which includes a wiring diagram of the circuit involved, brief description of operation of that specific circuit, and explanation of the purpose of significant steps in the chart.

SYMPTOM DIAGNOSIS RELATED TO SPECIFIC FUEL CONTROL SYSTEM

Section B contains driveability symptoms diagnosis procedures which are specific to each engine fuel system.

OPERATION AND SERVICING INFORMATION

Section C describes the basic operation of individual systems which are part of the computer controlled engine performance package. This section includes on-car service and diagnostic charts for each system along with carburetor calibration, idle speed control adjustment, mixture control solenoid and injector R&R, etc. Service Parts Catalog names and group numbers are also provided with the on-car service information.

We feel the expanded format of Section 6E will help you, the technician, more effectively diagnose and repair computer controlled fuel systems.

Images will be hard to read due to being on fax paper.

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.