What does cold start mean for a car?
2 Answers
Cold start of a car refers to starting the engine when the coolant temperature is low. The reasons for car cold start shaking include: 1. Dirty throttle or excessive carbon deposits in the fuel injector; 2. Fuel quality issues; 3. Failure of the coolant temperature sensor; 4. Unstable oil pressure; 5. Aging engine mounts; 6. Faulty spark plugs or ignition coils. The methods to address car cold start shaking are: 1. Read fault codes or data streams to rule out sensor failures; 2. Check if the exhaust gas valve has any issues; 3. Inspect spark plugs, high-voltage wires, ignition coils, fuel injectors, timing marks, fuel pump pressure, and cylinder pressure; 4. Check for problems with the idle speed motor, and clean the throttle and idle speed motor.
When I first started driving, I didn't understand what cold start meant either. Later, I figured out it refers to starting the engine when the car is completely cold. Especially on winter mornings, after the car has been parked overnight, the engine metal is ice-cold. At this point, the engine oil's fluidity becomes very poor, settling at the bottom of the oil pan, leaving the piston and cylinder walls in a state of dry friction. That's why the engine sounds particularly loud and shakes violently during startup—it's due to the lack of lubrication between parts. A mechanic once told me that cold start wear accounts for 70% of total engine wear. Later, I noticed on the car's computer that during cold idle, the RPM automatically revs up to around 1200 to warm up quickly. Now, I make it a habit to wait until the idle stabilizes at 800 RPM before driving off, giving the metal parts time to adjust to thermal expansion.
