What Causes Manual Transmission Car to Shake When Starting Cold but Not When Warm?
1 Answers
Here are the reasons why a manual transmission car shakes when starting cold but not when warm: 1. Low ignition energy causing shaking: The engine temperature is too low, and both fuel and lubricant temperatures are low. During a cold start, a richer air-fuel mixture is required, which demands higher ignition energy. Excessive spark plug gap or aging ignition coils and high-voltage coils can reduce ignition energy, causing the car to shake. 2. Incorrect air-fuel mixture ratio causing shaking: During a cold start, some engine sensors or signals from certain sensors may have significant errors, leading the ECU to make incorrect judgments. This results in errors in fuel injection timing and ignition timing control, causing engine shaking. 3. Uneven cylinder conditions causing engine shaking: In multi-cylinder engines, significant differences in ignition energy between cylinders, as well as varying degrees of wear on pistons and piston rings, can lead to inconsistent compression ratios. This results in uneven engine power output and causes engine shaking.