What holds the throttle shaft in idle position?

The throttle shaft is held in the idle position by a spring. This spring is typically located within the throttle body, and its tension is adjusted to ensure the correct idle speed. Here's how it works:

* Idle Speed Adjustment: The spring provides a constant force that pulls the throttle shaft closed, which in turn regulates the amount of air entering the engine. This is the baseline for idle speed.

* Throttle Position Sensor: A throttle position sensor (TPS) monitors the position of the throttle shaft and sends this information to the engine control unit (ECU).

* ECU Control: The ECU uses the TPS signal to determine the appropriate amount of fuel to inject into the engine. At idle, the ECU ensures a small amount of fuel is injected to maintain the desired engine speed.

Note: The actual mechanism for holding the throttle shaft closed can vary depending on the type of throttle body. Some use a spring directly attached to the throttle shaft, while others utilize a more complex system involving a vacuum diaphragm or a cable linkage.

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