HOLDEN GEN III V8, Обучение по обслуживанию

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GEN III V8 ENGINE MANAGEMENT
GENERAL INFORMATION
The GEN III V8 engine uses a Powertrain Control Module (PCM) to control exhaust emissions while maintaining
excellent driveability and fuel economy. The PCM maintains a desired air/fuel ratio at precisely 14.7 to 1 . To
maintain a 14.7 to 1 air fuel ratio the PCM monitors the output signals from two oxygen sensors. The PCM will
either add or subtract fuel pulses based on the oxygen sensors output signal. This method of feed back fuel
control is called closed loop.
In addition to fuel control, the PCM also controls the following systems.
• The Ignition Dwell
• The Ignition Timing
• The Idle Speed
• The Engine Electric Cooling Fans
• The Electric Fuel Pump
• The Instrument Panel Check Powertrain lamp
• The A/C Compressor Clutch
• The Automatic Transmission Functions
• The Manual Transmission Reverse Lockout
• Theft Deterrent
The PCM also interfaces with other vehicle control modules, such as the Powertrain Interface Module (PIM),
Instruments, and the Body Control Module (BCM). The illustration on the following page contains a list of the
various operating conditions sensed by the PCM on the left, and the various systems controlled on the right.
The PCM has a built-in diagnostic system that identifies operational problems at which time it stores a
Diagnostic Trouble Code (DTC) and on most occasions alerts the driver by illuminating the Check Powertrain
Lamp (CPL) in the instrument. If the lamp comes on while driving, it does not mean that the engine should be
stopped immediately, but the cause of the lamp coming on should be checked as soon as is reasonably
possible. The PCM has built in backup systems that in all but the most severe faults will allow the vehicle to
operate in a near normal manner until repairs can be made.
Below the instrument panel to the left of the steering column is a Data link Connector (DLC) which is used by
the assembly plant for a computer "check-out" of the PCM system. The DLC is also used in service to help
diagnose the system using Tech 2.
GEN III V8 ENGINE MANAGEMENT Page - 1