What are the effects of pressing the accelerator while depressing the clutch?
3 Answers
When the clutch pedal is fully depressed, the engine and transmission are disconnected. At this time, pressing the accelerator will cause the engine to idle. If the clutch pedal is not fully depressed and the clutch is not completely disengaged, pressing the accelerator pedal will cause the car to lurch forward and accelerate the wear of the clutch plates. Although engine idling does not cause immediate damage, frequent idling can lead to carbon buildup in the vehicle, which is harmful to the engine's intake and exhaust systems. Carbon deposits can block the idle channel, causing the idle control device to stick or exceed its adjustment range. This can result in low idle speed, idle shaking, failure of various auxiliary devices to accelerate, stalling when releasing the throttle, excessive exhaust emissions, and increased fuel consumption. Purpose of revving the engine without load: In cold winter weather, the atomization effect of the fuel injectors may be poor, making it difficult for some low-end cars to start. Revving the engine without load can help start the car by increasing the fuel injection volume, making it easier to ignite. However, repeatedly revving the engine too quickly can flood the spark plugs, making it impossible to start the vehicle.
I've been driving for over ten years and often encounter new drivers or even myself accidentally pressing the clutch while simultaneously stepping on the gas when parking on a slope. In such situations, the engine revs up with a loud roar, but the car remains completely still, just idling and wasting fuel. I remember once doing this for a long time during a traffic jam, and the fuel gauge dropped noticeably. The repair shop also mentioned that the clutch plate had developed small cracks due to overheating. Doing this frequently can accelerate engine wear, especially on the pistons and bearings, and also shorten the clutch's lifespan, doubling repair costs. Unless it's absolutely necessary to prevent rolling back on a steep slope, I think it's best to avoid developing this habit. Normally, when shifting gears, once the clutch is pressed, focus on selecting the gear without distraction—this saves fuel and protects your car.
I have some understanding of automotive mechanical principles. The clutch's function is to cut off power transmission, allowing you to shift gears smoothly, while the throttle controls the engine speed. When you press both simultaneously, the engine spins at high speed without load, burning a large amount of gasoline without delivering power to the wheels. This leads to a sharp increase in fuel consumption, loud noise, and causes high-temperature damage to components such as the flywheel and pressure plate, accelerating wear. I've seen data indicating this method can increase fuel consumption by 20% and halve the clutch's lifespan. It's recommended to use this technique only briefly in special situations like starting on snowy roads, and avoid making it a habit to prevent premature vehicle failure and costly repairs.
