Reasons and solutions for difficulties in starting diesel generators

There are more than ten or even dozens of reasons for the inability or difficulty of starting a diesel generator. This article describes reasons and solutions for difficulties in starting diesel generators. The following will provide a detailed introduction to the various reasons that cause the inability or difficulty of starting a diesel generator.

1、 White smoke emitted from the exhaust pipe during startup

1) Cause analysis

(1) There is a problem with the ventilation system: the valve clearance is incorrect, and the valve sealing has deteriorated; The air filter is severely clogged; Forgot to turn back the pressure relief handle.

(2) Problems with the fuel supply system, such as poor diesel quality and water ingress into the diesel tank; There is air in the oil circuit; Low pressure oil circuit blockage, clogged throttle filter screen, dirty filter element, clogged fuel tank cap vent, resulting in insufficient fuel supply; Oil supply time too early or too late.

(3) Engine body problem: cylinder head cracks; The cylinder gasket is not properly installed or burned out, causing water to directly enter the cylinder, etc; Problems with the crank connecting rod mechanism, such as incorrect clearance between the cylinder, piston, and piston ring, severe wear, or jamming; There is a problem with the engine starting device, such as low starting speed; The temperature is too low or the engine temperature is too low (especially in winter).

2) Find and troubleshoot faults

Generally, first check whether there is air or blockage in the low-pressure oil circuit, check the fuel delivery pump, and then check the high-pressure oil circuit and fuel injection pump. If there are no problems with the above inspection results, then check the fuel injector, ventilation system, crank connecting rod mechanism, engine body, etc. in sequence.

(1) If it is in winter or when the starting temperature is particularly low, you can try heating water into the water tank or draining the oil from the oil pan, heating it up, and then pouring it back in.

(2) If it is difficult to start. Firstly, check whether the air filter, fuel filter, and diesel filter are too dirty, then check the clearances of each fitting, such as cylinder, piston, and piston ring clearances, valve clearances, and finally check the fuel injector and fuel injection pump.

2、 Black smoke emitted from the exhaust pipe during startup

When the mixture of fuel and air is not completely burned and the diesel in the mixture is too rich, the unfinished mixture is emitted with black smoke.

1) Cause analysis

(1) There is a problem with the ventilation system: the air filter is clogged, which reduces the amount of air entering the cylinder and results in a richer mixture; The valve clearance is incorrect, causing insufficient intake and unclean exhaust; Insufficient elasticity of valve spring or spring breakage, causing valve leakage; There is carbon buildup and erosion between the valve and valve seat, causing valve leakage.

(2) There is a problem with the fuel supply system: one or several fuel injectors have severe carbon buildup, and the needle valve of the fuel injector is stuck, resulting in poor oil dripping or atomization quality; Insufficient fuel injection pressure, poor diesel atomization quality, and incorrect fuel supply advance angle; Excessive fuel injection from the fuel injection pump; The quality of diesel is poor.

(3) There are problems with the crank connecting rod mechanism, such as excessive clearance or severe wear between the cylinder, piston, and piston ring, resulting in insufficient cylinder pressure and incomplete combustion.

2) Find and troubleshoot faults

You can refer to the above methods for finding and eliminating white smoke to solve the problem. Special attention should be paid to using the cylinder cut-off method for cylinder by cylinder inspection.

3、 When starting, the exhaust pipe should be smoke-free

Diesel does not enter the cylinder, and the exhaust pipe only discharges air without smoke.

1) Cause analysis

There is a problem with the fuel supply system: the oil circuit is blocked, the fuel pump is not working properly, and the fuel injection pump is not working properly.

2) Find and troubleshoot faults

If the starting speed of the diesel engine is normal, but it cannot ignite and burn, or the exhaust pipe emits no smoke, it is a fault in the engine fuel supply system. Generally, the first step is to check whether the oil circuit is blocked. The specific method for checking the blockage of the oil circuit can be found in the previous section.

If there are occasional intermittent smoke emissions during startup, it indicates that some cylinders have diesel fuel entering while others do not. In this case, the “cut-off method” can be used, which means stopping the fuel supply to each cylinder separately and finding the cylinders that are not working.