Idle shaking of diesel engines is the most common and difficult fault, with causes covering multiple dimensions such as circuits, oil circuits, and mechanical structures, making troubleshooting difficult. Many maintenance personnel and users prioritize checking common parts such as fuel injectors, carbon deposits, spark plugs, and valve clearances, but ignore the core cause of diesel filters, resulting in repeated and incurable faults. Filter blockage, oil-water separation failure, oil intake, and wax blockage are hidden high-frequency causes of idle shaking. Mastering exclusive fault characteristics and troubleshooting methods can quickly and accurately solve problems.

The idle shaking caused by filter failure has exclusive recognition and can be clearly distinguished from mechanical faults. The core characteristic of the shaking caused by filter problems is "obvious idle shaking and disappearance of driving faults". When the engine is idling, the speed is unstable, the body vibrates slightly, the speed fluctuates between high and low, and even occasionally idles and stalls. However, when accelerating and driving the vehicle, the shaking symptoms are greatly reduced or completely disappear. The shaking caused by engine mechanical failure and valve failure will accompany the entire process of idling and driving, and is often accompanied by abnormal noise and severe power attenuation. At the same time, the shaking caused by the filter element is often accompanied by problems such as water accumulation alarm, difficulty in cold start, and increased fuel consumption, which can quickly assist in determining the root cause of the fault.

The four major filter related faults are the core causes of idle shaking, and corresponding clear troubleshooting and solutions are needed.
Firstly, the filter element is clogged, and the pores of the filter material are blocked by impurities and gum. Under idle conditions, the fuel demand is low and the fuel supply pressure is low, which easily leads to uneven fuel supply and unstable oil pressure, resulting in cylinder combustion imbalance and idle shaking. When troubleshooting, check the service life of the filter element. If the filter element is overdue or clogged, simply replace it with a new accessory and clean the impurities in the oil circuit to solve the problem.
Secondly, the oil-water separation fails, the aging filter cannot filter out moisture, and the combustion of water containing fuel is insufficient, causing idle shaking and white exhaust. Replacing the filter and thoroughly draining it can quickly repair the problem.
Thirdly, there is a malfunction in the oil intake system, where the filter element seal ring is aging, the drain valve is loose, and the pipeline joints are leaking, causing air to enter the sealed oil circuit, resulting in intermittent idle fuel supply and pressure fluctuations, leading to shaking. This fault requires a comprehensive inspection of all sealing parts of the filter element, replacement of aging sealing rings, tightening of loose pipelines, thorough emptying of the oil circuit air after replacing the filter element, and elimination of air resistance.
Fourthly, low-temperature wax deposition and blockage, winter wax crystal blockage of filter materials, insufficient idle fuel supply and unstable oil pressure. After the temperature rises, the symptoms will be relieved. It is necessary to replace the low-temperature adapted diesel and antifreeze filter element, melt the wax crystal, and clear the oil circuit.

In daily maintenance, it is necessary to abandon the misconception of "cleaning and reusing filter elements". After paper filter elements become clogged and aged, deep impurities cannot be removed by cleaning, and the filter material structure will also be damaged and ineffective. Although it appears smooth after cleaning, the filtration accuracy is completely lost, which can still cause shaking faults. The most direct and thorough way to prevent idle shaking related to the filter element is to replace it with a brand new high-quality filter element, synchronously clean the accumulated water and impurities in the oil circuit, and exhaust the air, which can completely restore the engine to a stable idle state and prevent the recurrence of faults.