What Causes Slight Idle Vibration After Replacing the Timing Belt?
2 Answers
Replacing the timing belt causes slight idle vibration due to incorrect timing or ignition system failure. Here are the reasons: Ignition system failure: After replacing the timing belt, first check whether the timing is correct. Improper assembly can cause idle vibration. Then check whether there is a fault in the ignition system. Poor performance of spark plugs, high-voltage wires, and ignition coils can also lead to unstable idle speed. Incorrect timing: If it is confirmed that the vibration is caused by replacing the belt, and the accessory model is correct, it may be necessary to check whether the timing points are aligned. Deviation can cause vibration and lack of power, so recheck it. The so-called timing belt must be aligned with the timing. The timing belt is one of the important devices of the valve train. If the marks are not aligned or there is an angle error, it will have serious consequences on the engine. In case of severe vibration, it is best to go to a 4S shop for inspection.
I've seen many similar cases in auto repair. The most common cause of idle vibration after replacing a timing belt is misaligned timing. Even the slightest deviation in marks can cause improper engine ignition timing, leading to uneven combustion and vibration. Improper belt tension is another critical factor; too loose and the belt may skip teeth, too tight and it accelerates bearing wear. Additionally, during old belt removal, the ignition system might get disturbed – issues like loose spark plug connections or aged high-voltage wires may surface. The ECU may also need time to adapt to the new belt's friction characteristics, sometimes requiring dozens of kilometers to stabilize. However, if left unaddressed, the vibration can worsen and affect valves, so I strongly recommend immediately returning to the workshop for rechecking timing alignment and component inspection.
