Electronic Fuel Injection Information; Electronic Fuel Injection System - PCM HO303 MPI Owner's Operation And Maintenance Manual

ELECTRONIC FUEL INJECTION INFORMATION - 4

ELECTRONIC FUEL INJECTION SYSTEM

The PCM Engines covered in this manual are equipped
with an Electronic Fuel Injection (EFI) system, which
allows precise control of fuel and spark delivery. The
fuel system components of the EFI system are:
• The electric fuel pumps
• The throttle body assembly
• The fuel injectors
The fuel injection system is controlled by an Electronic
Control Module (ECM). The ECM is the decision center
of the system. The ECM constantly monitors information
from various sensors on the engine, and electronically
processes the information, in order to control ignition
timing and fuel delivery for optimum performance
and fuel economy. The ECM incorporates an engine
overspeed protection, calibrated to a specifi c RPM, to
prevent engine damage from over-revving.
The sensors that the ECM monitors are:
• Engine Coolant Temperature (ECT) Sensor
• Throttle Position (TP) Sensor
• Manifold Absolute Pressure (MAP) Sensor
• Knock Sensor (KS) System
• Crankshaft Positioning (CKP) Sensor
• Camshaft Positioning (CMP) Sensor
• Intake Air Temperature (IAT) Sensor
• Throttle Control Position (TCP) Sensor
Additional Sensors for CES ENGINES
• Pre-Catalyst Oxygen (O 2 ) Sensors
• Post-Catalyst Oxygen (O 2 ) Sensors
• Exhaust Manifold Water Temp (EMWT) Sensors
If, for any reason, one or more of these sensors or
associated wiring malfunctions, the ECM's built-in self-
diagnostic system sets a trouble code and turns on the
"MIL" Malfunction Indicator Lamp to alert the operator of
a malfunction.
In most cases, when the "MIL" is on, the engine(s) may
lose some performance and/or effi ciency, but remain
running adequately. Also, the light may go out or
become intermittent, but a trouble code will be logged for
future diagnosis. (See Engine Alarm System - page 16)
In any case, the operator must obtain service by an
authorized PCM Premier dealer to determine the exact
cause of the malfunction.
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