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Inspection Method For Diesel Generator Can Not Start

Nov. 04, 2021

Diesel generators may sometimes experience abnormal phenomena such as failure to start fire, failure to start, abnormal smoke smell, etc. What is going on? Are there any good inspection methods? The following is announced by Starlight Power.


1. Normal starting speed, good cylinder compression, but no fire, and no smoke.

The main reason is that the low-pressure oil circuit does not supply oil. At this time, mainly check along the fuel tank, fuel pipeline, diesel filter, fuel delivery pump and fuel injection pump, etc. Generally, the faulty part can be found.


Poor filtration of diesel engine or irregular filter cleaning is the main cause of clogging of low-pressure oil circuit and filter. When judging whether the oil or the filter is clogged, the filter can be removed from the fuel pipe through the fuel injection pump. If there is a large amount of oil in the fuel tank, and there is little or no oil outflow from the filter, it means that the filter is clogged. If the fuel supply of the low-pressure oil circuit is good, the main reason for the high pressure and no oil of the diesel engine is the wear or improper assembly of the plunger and coupling of the fuel injection pump.


2. The operation is normal, the sound of oil pollution can be heard, but it cannot be started.

The main reason for this is the difference in cylinder pressure. A type 2105 and other diesel engine equipped with a decompression mechanism. If the decompression engine is in a non-decompression state, the diesel engine can still be turned briskly by the hand crank and the resistance is not large, and cylinder leakage can be judged.


After the exhaust valve leaks, the compression temperature and pressure of the cylinder block are not high, and diesel is difficult to burn. The main reasons for this kind of leak are: One is that the valve clearance is too small, which makes the valve not tightly closed. The other is valve sealing cone, or there are debris such as carbon deposits on the valve seal. When checking, you can shake the crankshaft. If you hear a "creak" sound from the air filter and exhaust pipe, it indicates that there is air leakage at the intake port.


When rotating the crankshaft, if you find that there is air leakage on the joint surface of the cylinder head and the body, it indicates that there is air leakage at the position of the cylinder head gasket. The cylinder head nut may not be tightened or loosened, or the cylinder head gasket may be damaged.


When rotating the crankshaft, there is a sound of air leakage inside the frame and the oil filler port, most of which are caused by the piston ring. In order to find out whether there is a bad cause and whether the piston ring is insufficient, an appropriate amount of clean lubricant should be added to the cylinder. If the oil is added to the cylinder, the cylinder pressure will increase significantly. The matching gap between the ring and the cylinder liner is too large, and air leaks into the crankcase between the piston ring and the cylinder liner.


diesel engine

If the pressure value does not change much after adding lubricating oil, it means that the lack of compression force in the cylinder has nothing to do with the piston ring, and it may be air leakage through the intake port or exhaust valve.


3. The diesel engine discharges abnormally.

(1) The main reasons for exhaust black smoke are:

① The diesel engine is overloaded and the speed is too low, the oil volume is small, and the combustion is incomplete.

② The valve clearance is too large. The cylinder pressure is low, resulting in improper installation of the timing gear. Leading to insufficient air intake and delayed fuel injection.

③ Low cylinder pressure, lower compression temperature, poor combustion.

④ Air filter clogged.

⑤ Each cylinder does not work or runs poorly.

⑥ Diesel engine temperature is low, and combustion rate is low.

⑦ Fuel injection time in advance.

⑧ The fuel supply of each cylinder of the diesel engine is uneven or there is gas in the oil circuit.


(2) The main reasons for white smoke emission are: ① The oil temperature of the diesel engine is too low.

② The fuel injection time is too late.

① There is water leakage or leakage in the fuel, and the water becomes white vapor after heating.

② Diesel engine oil circuit There is air in it, which affects fuel supply and injection.

③ Cylinder pressure is seriously insufficient.


The main reasons for the emission of blue smoke are:

① There is too much oil in the oil pool of the air filter, and the oil level is too high, resulting in excessive oil splashing into the cylinder wall and fleeing into the combustion chamber.

② In the oil pool or filter element of the air filter Too much oil on the cylinder.

③ The cylinder is not tightly closed, the piston ring is stuck in the ring groove, causing the piston ring to burn, incomplete opening and closing or overlapping openings, the matching gap between the piston and the cylinder is too large, or the chamfered ring Wrong installation.

④ The gap between the valve and the valve tube is too large, and the fuel is injected into the combustion chamber to burn.


Jiangsu Starlight Electricity Equipments Co.,Ltd. is one of the earliest manufacturers of generators and diesel generator sets in China. The company was established in 1974 and the company occupies an area. With an area of 86,000 square meters and a building area of 45,000 square meters, it has 64 sales and service departments across the country to provide users with one-stop service of design, supply, debugging and maintenance at any time. Welcome customers to come to consult and visit. Looking forward to your inquiry, please send email to us for details sales@dieselgeneratortech.com

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