What Causes Car Shaking When Starting Up?
2 Answers
Reasons for car shaking during startup include loose or severely worn components, warped, tilted, or deformed driven plates, poor clutch lining contact, weakened damping spring elasticity, clutch judder, and uneven pressure distribution between the driving and driven plates. Causes of car shaking when starting up: 1. Loose or severely worn components: Clutch control mechanism being locked or having loose connections, severe wear on the clutch spline hub, or a bent transmission shaft can cause clutch judder. Solution: Replace the corresponding parts. 2. Warped, tilted, or deformed driven plates: When the driven plate is warped, tilted, or deformed, the clutch lining will have irregular contact during engagement, preventing smooth pressure increase. Solution: Correct or replace the driven plate. 3. Poor clutch lining contact: Poor contact, surface hardening, or adhesive residue on the clutch lining can easily cause clutch judder. Solution: Reattach the clutch lining. 4. Weakened damping spring elasticity: Reduced elasticity of the clutch torsional damping spring, weakened clutch pressure spring elasticity, or cracks in the diaphragm spring can all cause shaking during clutch engagement. Solution: Replace the springs. 5. Clutch judder: Let the engine idle, engage a low gear, slowly release the clutch pedal, and accelerate to start. If the car shakes, it indicates clutch judder. Solution: Replace the damaged parts among the clutch three-piece set (flywheel, clutch plate, pressure plate). 6. Uneven pressure distribution between driving and driven plates: Inconsistent elasticity of the clutch pressure springs, uneven adjustment of the release levers, or uneven diaphragm spring release finger ends can cause asynchronous pressure application, uneven force on the pressure plate, or even tilting, leading to poor contact between the driving and driven plates and clutch judder. Solution: Replace the clutch pressure springs and level the release levers.
My car occasionally shakes when starting, which is a fairly common issue. It could be caused by aging spark plugs or damaged ignition coils leading to incomplete ignition; a dirty air filter clogging the intake and affecting combustion efficiency; excessive carbon buildup in the engine, especially after short trips, where incomplete fuel combustion can cause shaking; or fuel system problems, such as clogged fuel injectors or insufficient fuel pump pressure, which are particularly noticeable during cold starts. Insufficient or overly viscous engine oil, leading to inadequate lubrication, can also cause shaking. Faulty or unstable sensors, like the idle control valve, or even worn engine mounts can transmit vibrations to the car body. It's recommended to first check basic components like spark plugs, the air filter, and engine oil. If the issue persists, consult a professional mechanic for a thorough inspection and repair.
