What Causes the BYD DM-i Engine to Shake?
3 Answers
DM-i engine shaking can be caused by severe engine carbon buildup, ignition system failure, or unstable oil pressure, as detailed below. Severe Engine Carbon Buildup: The most common cause of car shaking is a dirty throttle body or excessive carbon deposits in the fuel injectors. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold-start injector is largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making it difficult to start. Ignition System Failure: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or spark plugs can also lead to such issues. Unstable Oil Pressure: If you have already cleaned the engine carbon deposits, cleaned the throttle body, and replaced the spark plugs but still notice the car shaking at idle, you can check whether the fuel supply pressure and intake pressure sensor are functioning normally. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can both cause the car to shake.
When driving my BYD DM-i, I often encounter engine vibrations, which are mostly due to aging engine mounts—specifically, the deterioration of the engine mount bushings leading to reduced damping effectiveness. The DM-i is a hybrid system where the engine only starts when needed, leading to more carbon buildup and incomplete combustion, making the vibrations more noticeable. During my last maintenance visit, the technician mentioned issues with the ignition system, such as aging spark plugs or faulty ignition coils, causing unstable ignition. Clogged fuel injectors are another common factor, as uneven fuel injection affects power output. Minor bugs in the control system, if they cause rough engine start-stop cycles, can also trigger vibrations. It’s recommended to regularly clean the throttle body and drive at high speeds to clear carbon deposits. Ignoring these issues may increase fuel consumption or even damage other components, so I insist on a comprehensive annual inspection to maintain the vehicle’s health.
Shaking issues can be quite annoying. I often see them occurring in fundamental components on BYD DM-i models, such as damaged engine mounting brackets failing to properly absorb vibrations. Ignition-related problems are common—spark plugs may lose strength when reaching the end of their lifespan, or faulty coils can cause unstable combustion. If fuel injectors get clogged with impurities, uneven fuel spray can also lead to shaking. The hybrid design, with its frequent engine start-stop cycles, accelerates carbon buildup and worsens the issue. Sensor inaccuracies causing misjudgment in start-stop timing by the control system are another contributing factor. Don’t neglect routine maintenance—start by checking simple parts like spark plugs and brackets, then take a high-speed drive after replacements. If shaking occurs, pull over promptly and use diagnostic tools to read error codes, ruling out major problems to avoid costly repairs later.
