Reasons for the Car Stalling Immediately After Starting?
3 Answers
Reasons for the car stalling immediately after starting are as follows: 1. Carbon deposits. Cold starts cause the engine temperature to be low, making fuel difficult to vaporize. Severe carbon buildup in the fuel lines, intake passages, and other areas can lead to excessively lean air-fuel mixture entering the cylinders for combustion, resulting in unstable idling, immediate stalling after ignition, and other phenomena. 2. Fuel and air issues. Insufficient fuel supply due to low fuel system pressure, fuel line leaks, small supply current, or a damaged fuel pressure regulator; clogged or leaking fuel injectors causing poor atomization, leading to insufficient fuel supply and stalling. 3. Ignition problems. Issues such as faulty ignition coils, spark plug wires, or spark plugs can cause insufficient ignition energy, leading to stalling. 4. Power supply issues. Faults in the starter motor or battery can make it difficult or even impossible to start the engine.
Last time my car stalled during a cold start, the mechanic said it could be one of these common issues. In the fuel system, insufficient fuel pump pressure or clogged fuel injectors can lead to inadequate fuel supply. Spark plug carbon buildup or aging ignition coils can cause misfiring after ignition. Air leaks in the intake system or throttle body carbon buildup and sticking can also make the RPM unstable and cause stalling. If the crankshaft position sensor fails, the engine control unit won't receive any RPM signal and will cut off fuel directly. The most frustrating issue is when the anti-theft system mistakenly triggers and locks the fuel injection, requiring a re-match of the key chip. Remember to listen for the fuel pump humming sound during startup and check if the EFI fuse in the fuse box is blown—these are things you can check yourself initially.
When I encountered this situation, I found the idle air control valve sticking to be particularly typical. During cold starts, the RPM would fluctuate wildly like a roller coaster for a few seconds, sputter a few times, and then stall. The mechanic used a diagnostic tool to read the P0505 trouble code, and upon removing the throttle body, it was completely covered in black sludge. Another time, it was due to the mass air flow sensor data drifting, causing the ECU to miscalculate the air intake and misfuel. When using poor-quality fuel, injector gum deposits can also easily cause this, and adding some fuel system cleaner before highway driving can help alleviate it. If the car stalls when warm, you need to check the purge valve; if it's stuck open, it can cause the mixture to run too rich. For older cars, pay attention to oxidized ground wires, as poor signal transmission can cause the ECU to send erratic commands.
