Symptoms of diesel knock appears in the job process are: from speed to low speed, will issue heavy knocking sound, exhaust black smoke, and when put guns or flame out, the engine overheat. The main causes of knocking are:

　　1. Diesel oil too early when the upward movement of the piston sleeve machine has not reached a predetermined injection position, injector start fuel injection, combustion of fuel in advance, the impact of high pressure gas cylinder piston, given the rhythmic "despair, despair "Knocking sound crisp, reduce the throttle, Knocking sound obvious.

　　Remedy are: fuel supply advance angle adjustment, an increase of fuel pump and gear box gaskets between the fuel supply time delay to comply with the provisions of injection time. For each additional 0.1 mm spacer, supply advance angle can be delayed 1.3-1.7.

　　2. Adverse injection pressure is too low fuel burn, fuel injector drip, bad injector atomization and oil too late, and this will adversely fuel burn and cause knocking. Knocking sound such failures caused by low, husky voice and accompanied by engine overheating, black smoke or exhaust pipe blasting, flame and so on. Remove the injector should be checked and adjusted, adjust injection timing, replace with new parts if necessary, to conform to regulations.

　　3. Oil valves wear out after valve wear, on the one hand decompression valve seat ring and bore with the gap becomes larger, sealing deteriorates, pressure starts to deteriorate; the other - within the terms of the remaining high-pressure tubing pressure is too high, for oil increases, causing fuel deflagration and knock. Knocking sound is reduced when the throttle is particularly evident.

　　Remedy is to replace the valve and seat, hand machine need to be reminded to note that intact state of the art diesel engine running at low speed, sometimes given the rhythmic percussion, which is the fuel combustion process dramatically airflow pressure percussion shock wave generated due to increase, sailing is mentioned Knocking front.