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The Uneven Fuel Delivery Of The Fuel Injection Pump Will Affect Starting

Jan. 06, 2023

The fuel supply of the diesel generator fuel injection pump is uneven (that is, the fuel supply of the fuel injection pump to each cylinder is inconsistent). The uneven fuel supply will cause the diesel engine to work unstably, reduce the power, and the exhaust pipe will periodically emit black smoke. In addition, too early or too late fuel supply time of the fuel injection pump will also affect the difficulty of starting the diesel generator.


1、 The main reasons for the uneven fuel delivery of the fuel injection pump are as follows.

① The wear of each plunger and sleeve is inconsistent or individual plunger spring is broken.


② Some oil outlet valves are not closed tightly.


③ Individual adjusting gear ring is improperly installed or the locking screw is loose and displaced.


④ Inconsistent wear of tappet rollers or cams leads to uneven oil supply.


⑤ Air is mixed in the fuel injection pump, which makes the fuel supply of individual cylinders insufficient, causing the diesel engine to work unstably.


The inspection method is generally cylinder cutoff method. For a single injection pump diesel engine, lift the handlebar of one cylinder to make one blood out of service. Check the frequency meter for the degree of decline. Check whether the frequency drop is consistent when each cylinder is out of service. If not, it means that the fuel supply of the two straight injection pumps is uneven. For the combined fuel injection pump, such as the 135 series diesel engine, the way to break the cylinder is to use a large screwdriver to jack up the plunger spring of a cylinder. The inspection method is the same as that for the single fuel injection pump, that is, to see the degree of decline of the frequency meter and whether each cylinder is consistent.


diesel generator

2、 The fuel injection pump supplies fuel too early.

When the fuel supply time is too early, the cylinder will emit rhythmic and crisp "dang, dang" metal knocking sound, which makes it difficult to start, the diesel engine is not working smoothly, and the power is insufficient. The exhaust gas emits white smoke and has the smell of "oil generation". It is easy to stop at low speed.


The reasons are as follows:

① The fixing screws of the connecting plate of the coupling are loose and displaced (this causes the total oil supply time to be too early).

② The adjusting screw on the fuel injection system tappet is improperly adjusted or moves.

③ Some oil outlet valves are not closed tightly.


Solution: During inspection, remove the high-pressure oil pipe of the first cylinder, rotate the crankshaft, and observe the oil level in the tight seat of the oil outlet valve on the fuel injection pump. At the moment when the oil level just fluctuates, check whether the injection advance angle of the diesel engine conforms to the regulations from the fuel supply timing scribe on the flywheel and the mark on the flywheel housing. If not, it shall be readjusted and checked cylinder by cylinder if necessary.


3、 Fuel supply time of fuel injection pump is too late.

When the fuel injection time is too late, it is difficult for the diesel engine to start. After starting, there is a low and unclear knocking sound in the cylinder. The speed of the diesel engine cannot increase with the increase of the throttle, and the engine temperature is high. Power decreases, fuel consumption increases, black smoke, etc. The inspection method is the same as that for the premature fuel supply time.


The causes are as follows:

① The fixing screws of the coupling connecting plate are loose and displaced;

② The adjusting screw on the fuel injection pump tappet is improperly adjusted or moves.

③ The driving gear, tappet, cam, plunger and sleeve of the fuel injection pump are excessively worn.


Jiangsu Starlight Electricity Equipments Co.,Ltd. is one of the earliest manufacturers of generating sets in China. It has first-class testing equipment, advanced production technology, professional manufacturing technology, perfect quality management system, and strong R&D technical strength. It can provide 3KW-2500KW various specifications of universal, automatic, four protection, automatic switching, low noise and mobile, etc., high-quality, low-energy generating sets to meet all customers' power needs, and can also meet users' different voltages and different Frequency requirements, as well as the parallel-connected power supply system of multiple units, use excellent talents to build excellent enterprises, create excellent products, create excellent services, and strive to build excellent domestic enterprises. For more product details, please contact us with sales@dieselgeneratortech.com.

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