Throttle valve — general information (Escort 4)

The throttle valve is mounted in the throttle body of the CFI unit under the injector just before the intake manifold and is connected to the accelerator pedal by a flexible cable.

Throttle Position Sensor

The throttle position sensor (rotation potentiometer) transmits information about the throttle position in the form of voltage signals to the EEC-IV device, which thus determines the engine operating modes:

• closed throttle valve for idle speed control;
• partially open throttle for normal engine load conditions;
• wide open throttle for enrichment at full load or when starting;
• different degrees of throttle opening for enrichment during acceleration.

Throttle control motor

This motor, mounted on the side of the injection unit, controls the final position of the throttle valve and thus the idle speed. The idle position of the throttle valve means for the EEC-IV device:

• at idle speed, the throttle motor controls the engine speed and maintains it constant. When the engine is loaded due to any consumer, the throttle motor receives a signal from the EEC-IV device to open the throttle valve until the idle speed stabilizes at a preset value;
• when decelerating, if the accelerator pedal is released slightly or if, with the accelerator pedal fully released, the engine switches to forced idle mode, the EEC-IV device, in accordance with the change in vacuum in the intake manifold, issues a corresponding signal to the throttle motor.
• This signal prevents the throttle valve from closing abruptly and ensures its gradual closing in accordance with the reduction in rotation speed. As a result, the proportion of incompletely burned hydrocarbons in the exhaust gases is reduced:
• when the engine stops, the EEC-IV device remains energized for 6 seconds thanks to the power relay. As a result, the EEC-IV device can send a signal to the throttle motor to close it completely. After a while, the throttle motor opens it again. This ventilation of the intake manifold makes it easier to start a warm engine;
• as soon as the engine starts again, the throttle motor moves it to the required position. The current engine temperature is taken into account, so that when starting the engine, there is no need to press the accelerator pedal.

[The original article is available on the website FordBook.ru]