Festiva L4-81 1.3L SOHC EFI (1989)
The engine coolant temperature (RAD) switch is mounted in the radiator and senses coolant temperature inside the radiator. The RAD switch is closed
below 17~C (63~F). This information is also sent to the ECA for use in calculating fuel injection amount.
Barometric Pressure Sensor
The barometric pressure (BP) sensor is located inside the ECA. It senses atmospheric pressure.
Exhaust Gas Oxygen Sensor
The exhaust gas oxygen (EGO) sensor is mounted into the exhaust manifold and senses the oxygen concentration in the exhaust gas. It sends this
information to the ECA for use in determining fuel injection amounts. The sensing element is made of zirconia ceramic with platinum coating.
Throttle Position Sensor
The throttle position (TP) sensor consists of a lever attached coaxially to the throttle valve, a guide cam driven by the lever, and movable idle and power
contacts. It detects idle and high load conditions based on the opening of the throttle valve. The sensor sends a signal to the ECA when the throttle is in
the following positions:
^
IDL-Throttle valve opening 1.5~ or lower (idle or deceleration)
^
PSW-Throttle valve opening 70~ or more (heavy load condition).
Neutral Safety Switch
Vehicles equipped with an automatic transaxle have a neutral safety switch mounted on the transaxle. The switch informs the ECA when the transaxle is
in the neutral or park position.
Ignition Switch
The ignition switch informs the ECA of the key position. This information is used in calculating fuel injection amounts.
A/C Switch
The A/C switch informs the ECA when the A/C system is operating.
Battery
The battery supplies the ECA with keep alive power. This allows the ECA to remember service information after the key is turned off.
Outputs
Injectors
The fuel injectors are electromechanical devices which supply metered and atomized fuel to the engine. The amount of fuel supplied to the engine is
controlled by how long the injection solenoid coil is energized (pulse width). The ECA controls the pulse width according to the inputs received from the
various engine sensors. When the injectors are energized, the needle valve is pulled off its seat. Fuel is then injected around the back face of the intake
valve
Canister Purge Valve The canister purge valve opens and closes the evaporative vapor passage based on a duty signal from the ECA.
Idle Speed Control-Bypass Air
The ECA controls both the idle speed and the bypass air functions. The bypass air valve is open when the coolant temperature is below 60~C (140~F).
BASE ENGINE STRATEGY
To control the system in the wide range of conditions found during normal driving, the base engine strategy uses several different operating modes to
provide the correct air/fuel ratio to meet the demand of specific engine and driving conditions. The base engine strategy can be divided into the following
operational modes.
1989
24-05-11
Electronic Fuel Injection System
24-05-11
