What are the possible causes of a car not starting?

[VonBenjamin]

When a car fails to start, the following diagnostic steps should be taken: 1. Check the battery: The first step is to inspect the battery. Determine if the battery charge is insufficient. 2. Check ignition timing: A slipping timing belt is the fundamental cause of no spark generation and engine failure to start. 3. Inspect the starting system: The starting system circuit typically includes the battery, starter motor, and connecting cables. Additionally, components like the ignition switch, starter relay or solenoid, and the vehicle's anti-theft system are also crucial parts of the starting system. 4. Test spark quality: Use a spark tester to examine the quality of the spark. 5. Diagnose the fuel system: Fuel system diagnosis can be divided into two parts: fuel supply system diagnosis and injector circuit diagnosis. The fuel supply system can be checked by measuring fuel flow rate and pressure. The best method to measure fuel flow is to test the fuel line under load conditions.

[AlanDella]

A few days ago, my car suddenly wouldn't start. I was in a hurry to get to work early in the morning, but when I pressed the key, there was no response at all, and even the headlights were dim. I quickly asked a friend to help with jumper cables, and the battery voltage measured only a little over 9 volts—completely dead. My friend at the repair shop explained that failure to start a car is often due to a dead or aging battery, especially in cold weather when it's prone to discharging. Issues with the starting system are also common, such as a damaged starter or solenoid failure, where you might only hear a clicking sound when trying to start. Ignition system problems, like burnt spark plugs or disconnected high-voltage wires, can prevent the engine from firing. Fuel-related issues, such as a non-working fuel pump or a clogged filter, can lead to insufficient fuel supply. Other details include loose electrical connections or blown fuses. He reminded me to regularly check the battery's lifespan, avoid using in-car electronics for extended periods while parked, and not to force-start the car if there's a starting issue—instead, test the voltage or do a simple check first. It's best to get a comprehensive inspection during annual maintenance—prevention is better than repair.

[VonJayla]

There are various reasons why a car won't start. I've encountered several instances, which can be mainly categorized into the following: First, battery-related issues, such as insufficient power or corroded terminals, which can be judged by observing headlight brightness; Second, starting system failures, commonly caused by a damaged starter motor, resulting in no sound or just a single click when attempting to start; Third, ignition system problems, like failed spark plugs or aged ignition coils; Fourth, interrupted fuel supply, due to a broken fuel pump or clogged fuel lines; Other causes include ECU errors, blown relays, or activated anti-theft systems. For simple checks, you can start by testing the battery voltage, then use a stethoscope to listen for the fuel pump sound. For more complex issues, using an OBD tool to read fault codes is advisable. Regular maintenance, such as changing engine oil and cleaning battery terminals, is crucial, especially in humid climates where wiring is prone to oxidation and problems.

[LeilaLynn]

I often repair my car myself. When the car won't start, I follow these troubleshooting steps: First, check the battery voltage—it should be above 12 volts; if it's low, charge it. Next, listen for the starting sound—if there's no sound, it might be a blown fuse; if there's an abnormal noise, the starter might be faulty. Then, pull out the spark plug to check for ignition—if there's no spark, inspect the coil. After that, confirm whether the fuel pump's humming sound is normal during operation. Simple issues like cleaning terminals or refueling can often solve the problem. Don't forget to replace the battery regularly and check the fuel system to prevent minor issues from becoming major problems.