Honda Civic Service Manual page 233

Fuel and Emissions Systems
System Descriptions (cont'd)
PGM-FI System
The Programmed Fuel Injection (PGM-Fl) system is a
sequential multiport fuel injection system.
Air Conditioning {A/C) Compressor Glutch Relay
When the ECfM receives a demand for cooling from the
Ay'C system, it delays the compressor from being
energized, and enriches the mixture to assure smooth
transition to the AVC mode.
Air Fuel Ratio lA/Fl Sensor
The Ay'F Sensor operates over a wide airlfuel range. The
Ay'F Sensor is installed upstream of the TWC, and sends
signals to the ECM which varies the duration of fuel
injection accordingly.
SENSOR
TERMINALS
HEATER
TERMINALS
Barometric Pressure {BAROI Sensor
The BARO sensor is inside the ECM. lt convens
atmospheric pressure into a voltage signal that the ECM
uses to modify the basic duration of the fuel injection
discharge.
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ELEMENT
HEATER
11-26
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Camshaft Position (CMPI Sensor B (Top Dead Center
(TDCI Sensor)
The CMP sensor B (TDC sensor) detects the position of
the No. 1 cylinder as a reference for sequential fuel
injection to each cylinder.
Crankshaft Position (CKPI Sensor
The CKP sensor detects crankshaft soeed and
determines ignition timing and timing for fuel injection
of each cylinder as well as detecting engine misfire.
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is a temperature dependent resistor
(thermistor). The resistance of the thermistor decreases
as the engine coolant temperature increases.
MAGNET
TERMINAL