Cause diagnosis and treatment of sticking failure

2022-08-09
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Cause diagnosis and treatment of stuck fuel injection pump

fuel injection pump is the heart of diesel engine fuel supply system. We believe that the precision coupling in the fuel injection pump is stuck behind, which will lead to unstable engine speed and, in serious cases, engine flameout and runaway accidents

1 reasons for fuel injection pump stagnation

for old fuel injection pumps, the stagnation reasons are mostly caused by dirty diesel oil, mechanical impurities between the plunger and the plunger sleeve, or the surface of the plunger and the plunger sleeve is strained, or the top corner of the plunger is bumped to produce burrs

for the new fuel injection pump, the reasons for its stagnation are as follows:

(1) at present, some fuel injection pump manufacturers and maintenance units do not pay attention to the selection of high-quality diesel when debugging the fuel injection pump, resulting in a large actual colloid content and high acidity in the diesel used for debugging. After such debugging, a layer of residual oil film is adhered to the mating surface of the precision coupling of the fuel injection pump. If the fuel injection pump is stored for too long, this layer of oil film will gradually form organic sediment and glue, and after installation, a series of chain reaction stagnation caused by overload will occur

(2) poor storage and storage of fuel injection pump, loose packaging, missing or damaged moisture-proof and rust proof materials, damage or loss of oil pipe joint dust cap, etc. will also produce stuck phenomenon

2 card lag processing

for the old 6 in use To stop the experimental explosive fuel injection pump, you can find the stuck plunger coupling and remove it, and clean it with clean diesel oil. If the plunger coupling is strained by mechanical impurities, it can be washed and ground with clean engine oil. If the plunger top is bumped to produce burrs (it is difficult to observe with the naked eye), when the plunger top is retracted into the plunger sleeve, it will cause astringent hairpin. At this time, do not rotate or pump the plunger repeatedly to avoid burrs scratching the plunger sleeve. The correct treatment method is: pull the top corner of the plunger to be flush with the center of the plunger sleeve into the oil hole, and slowly rotate the plunger, which will feel blocked at this time. When the blocking feeling disappears when turning to a certain position, That is, it shows that the bumping part of the top corner of the column plug is right in the plunger sleeve, and the condenser is adjusted to the center of the field of vision (most research microscopes you can use must do this action at the oil hole. Remember the position, push the edge angle of the plunger top out of the plunger sleeve, and use a fine sand bar to grind the bumped parts. When grinding, the plane of the fine sand bar is 45 with the plunger axis, gently push and pull a few times to eliminate the edges and burrs. However, do not grind too much, so as not to affect the consistency of the starting angle of oil supply and the uniformity of oil supply of each cylinder.

for a new fuel injection pump that is stuck, you can The following methods are adopted:

(1) inject an appropriate amount of gasoline or diesel into the fuel injection pump and governor, rotate the camshaft repeatedly to make the fuel injection pump tappet and governor flying ball and other components move freely, so as to prevent rust and hairpin, resulting in diesel engine flying

(2) for the fuel injection pump whose upper and lower bodies can be disassembled, the pump body can be placed flat, the side cover plate can be opened, the fastening nut of the pump head can be removed, the pump head can be removed, the plunger root of the plunger can be clamped with pliers, the plunger and spring of the faulty cylinder can be slowly extracted (pay attention not to damage the plunger), the plunger and spring of the faulty cylinder can be cleaned repeatedly with clean gasoline or diesel, and then it can be reinstalled after cleaning (pay attention that the plunger adjusting arm must be installed in the adjusting fork), and the pump head nut can be tightened alternately, and the camshaft can be, Pull the operating handle of the oil pump for recheck

(3) for the integral fuel injection pump, open the side cover plate, rotate the camshaft, insert the driver into the stuck plunger spring bracket and gently pry it, force the plunger to go down and reset, inject clean gasoline or diesel into the plunger root exposed outside the plunger sleeve, and rotate the camshaft. After the plunger moves back and forth freely and the two racks move back and forth sensitively, drain the cleaning oil and inject an appropriate amount of clean lubricating oil into the governor housing

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