Under what circumstances will a car stall?
3 Answers
A car may stall due to the following reasons: unskilled driving techniques or improper operation; fuel pump stuck or malfunctioning leading to poor fuel supply; use of low-quality fuel causing excessive engine carbon buildup; faulty spark plugs or ignition coils resulting in multiple cylinders failing to ignite; excessive dirt accumulation on the idle control valve core and throttle body. Low-quality fuel: For automatic transmission cars, stalling is mainly caused by the use of low-quality fuel. One solution is to refuel at reputable, large-scale gas stations with higher-octane fuel, such as using 97-octane gasoline. Although more expensive, it ensures longer vehicle lifespan and better driving performance. Excessive dust: The main cause of stalling during idle is excessive dust in the air. When the engine is running, dirt accumulates on the idle control valve core and throttle body. When too much dirt builds up, the engine will have low idle speed, unstable idle operation, and may stall during idling. This issue can be resolved by simply cleaning the idle control valve.
I've been driving a taxi for almost twenty years and have seen all kinds of stalling situations. The most common is an aging battery, especially on winter mornings when the voltage isn't enough to start the engine—it just gives up. Fuel line issues are also frequent; when the tank is nearly empty, the fuel pump can't draw fuel, and the car just stops mid-drive. Manual transmission drivers dread hill starts the most—if you release the clutch too quickly, the engine stalls immediately, and the honking from cars behind can sound like a symphony. Once, while taking a passenger to the airport, I suddenly lost power on the highway. I slowly pulled over and found that the alternator belt had snapped, cutting power to the entire car and forcing it to shut down. Regular throttle cleaning is also crucial—too much carbon buildup can cause unstable idling, and the engine might stall inexplicably at red lights. I’ve also learned the hard way that low-quality gasoline can make the engine act up.
Over the years of car repair, stalling issues are encountered daily. A faulty fuel pump is the most common culprit – the engine may suddenly cut out even before the fuel warning light illuminates. Ignition system failures also occur frequently, such as excessive spark plug gaps or leaking high-voltage wires, particularly prone to stalling during acceleration. Loose battery terminals can cause a complete power loss, leaving no response when turning the key. Automatic transmission owners, beware: torque converter failure can interrupt power transmission, causing the vehicle to stop abruptly while driving. A malfunctioning crankshaft position sensor will make the ECU shut down the engine directly due to signal loss. Sticking transmission valve bodies can also trigger stalling, especially noticeable during cold starts. During routine maintenance, remember to check the generator brushes – excessive wear prevents proper charging, eventually draining the battery and causing stalling.
