What Causes Vehicle Shaking During Startup?
1 Answers
When starting the vehicle, the clutch will be in a semi-engaged state, which can cause a certain degree of slight shaking. This is a normal situation. Additionally, if starting on a slightly inclined surface without applying throttle, the shaking can be more noticeable. Several reasons for engine shaking during startup are as follows: 1. Incorrect air-fuel mixture ratio: Almost all fuel-injected vehicles now use closed-loop control, which monitors both the density of the air-fuel mixture before combustion and the density of the mixture in the exhaust gases after combustion to ensure the engine is operating normally. In vehicles with closed-loop control, the oxygen sensor's minimum operating temperature is 370 degrees Celsius. If the vehicle has just been started, the temperature in the exhaust pipe may not reach 370 degrees Celsius, causing the oxygen sensor to not function. If the ECU makes an incorrect judgment at this time, errors in controlling the air-fuel mixture and ignition timing through the actuators can lead to a completely chaotic air-fuel mixture ratio. 2. Carbon deposits on valves and intake passages: If carbon deposits form on the valves and intake passages inside the engine, they can absorb a certain amount of fuel (similar to how soil absorbs water as it flows over a riverbank), leading to ECU misjudgment. For example, if the ECU controls the injection of what it assumes to be 100L of air-fuel mixture, but only 90L actually enters the cylinder, even if the remaining 90L mixture burns completely, it still won't provide the required power, making shaking inevitable.
