Why does the car fail to start on the first attempt when cold but succeeds on the second try?

[McTeagan]

There are several reasons why a cold car fails to start on the first attempt but succeeds on the second try: 1. Check the spark plugs: Inspect the ignition and combustion condition of the spark plugs. The ignition energy of the spark plugs directly affects combustion in the cylinder, thus impacting startup. Therefore, the first step is to check the spark plugs. 2. Clean the fuel injectors: Poor atomization of the fuel injectors also affects combustion and can cause difficulty in starting. A key function of fuel injectors is to atomize fuel for complete combustion. 3. Check fuel pressure: Insufficient fuel pressure or poor supply can lead to inadequate fuel injection, affecting startup. A clogged fuel filter or a leaking pressure valve on the fuel pump can cause fuel pressure loss in the fuel lines, requiring pressure to be rebuilt each time the car starts. This is the most critical and easily overlooked issue. 4. Charcoal canister solenoid valve: This is another easily overlooked component. The charcoal canister solenoid valve controls the entry of fuel vapor from the fuel tank into the engine for combustion. If too much fuel vapor enters the engine, it can cause an overly rich air-fuel mixture, leading to difficulty in starting. 5. Excessive carbon buildup can also cause starting difficulties: This is the hardest issue to address. For naturally aspirated engines, carbon buildup under normal usage within 80,000 kilometers usually doesn’t have a significant impact. However, direct-injection turbocharged engines tend to have more severe carbon buildup by 80,000 kilometers compared to naturally aspirated engines.