What Causes the Throttle to Automatically Increase When Pressing the Clutch in a Car?
2 Answers
The reasons why the throttle automatically increases when pressing the clutch in a car are: 1. The clutch switch has fallen off or is damaged, causing a sudden increase in engine speed; 2. There is a leak in the engine intake vacuum line, leading to an increase in engine speed that does not decrease; 3. The throttle valve body is too dirty or stuck, preventing the speed from decreasing. The working principle of the clutch is: 1. When the inner race is fixed, the outer race rotates clockwise, and the wedge block does not lock, allowing the outer race to rotate freely; 2. When the outer race rotates counterclockwise, the wedge block locks, preventing the outer race from rotating. The function of the throttle is: to control the cylinder's filling volume by adjusting the carburetor's throttle opening and to regulate the fuel flow through the fuel regulator, determining the engine's output power and generating thrust.
I've been driving manual transmission cars for over a decade. The most common reason for automatic throttle increase when pressing the clutch is the engine control computer automatically adjusting to maintain idle speed. When you disengage the clutch, the engine load suddenly decreases, and the computer opens the throttle to prevent stalling - it's like a self-protection mechanism. A slight RPM increase is normal, but if it surges too high (say, over 3000 RPM), there might be an issue. Potential problems include carbon buildup or malfunction in the throttle position sensor causing signal errors, or a stuck idle control valve sending incorrect commands. I remember this happening frequently when my car got older - cleaning the throttle body and checking wiring solved it. Long-term neglect can increase wear, raise fuel consumption, and even affect driving safety. I recommend first checking idle stability yourself; if abnormal, get it repaired promptly before it becomes a major issue.
