QUANCHAI N485D, Руководство по обслуживанию

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ANHUI QUANCHAI ENGINE CO., LTD
20. Failure of engine to be started
The prerequisite for the diesel engine to work normally is that the well atomized diesel can be injected into
the combustor accurately and timely, and that the compressed air in the combustor must reach sufficient
temperature before ignition and explosion. To meet the two conditions, there must be high enough rotating
speed and certain temperature in the cylinder when the diesel engine is started. When the diesel engine cannot
be started, the starting system and the fuel supply system shall be checked first.
Abnormal conditions for starting system:
The starting speed is low or the starting system does not work. If the ambient temperature is too low, the
diesel engine shall be preheated first, otherwise it is not easy to be started. If the starting speed is extremely
low, it is largely due to the starter is under-power. The electrical circuit shall be checked carefully to
determine whether the storage battery is fully charged, whether the lead wires are connected tightly and
whether the starter works normally (see details below).
Abnormal conditions for fuel supply system:
1) There is no fuel in the fuel tank or the fuel tank is not switched on.
2) There is excessive air or water in the fuel supply system. In such case, the starting speed is not low but the
engine fails to be started, and the exhaust pipe emits white smoke. The check method is to loosen the bleeder
screw on the diesel filter or the high-pressure fuel pipe on the high-pressure pump. If bubbles come up, it
means there is air in the fuel supply system. The air may be removed by tightening the joints of the oil circuit,
then loosening the bleeder screw on the high-pressure pump and turning the crankshaft. Water found in diesel
can also be removed by the same method. If there is too much water in the diesel, replace the diesel.
3) The pipeline or filter is blocked. The solution is to blow through the pipeline with an air cylinder, clean the
filter, and check whether the filter screen at the fuel tank filler is in good condition.
4) The plunger of the fuel injection pump is worn. In this case, the plunger shall be replaced.
5) The outlet valve of the fuel injection pump is stuck or the outlet valve spring is broken. A feasible solution
is to remove the high-pressure fuel pipe joint, then take out and clean the outlet valve and the valve seat. The
outlet valve spring needs to be replaced when it is broken.
6) The plunger spring of the fuel injection pump is broken, resulting in no pressure on the fuel injection pump.
7) The plunger of the fuel injection pump is stuck in the plunger sleeve. In case of normal oil circuit, if the
plunger does not move when the crankshaft is shaken, it means that the plunger and plunger sleeve are stuck.
The solution is to disassemble the fuel injection pump and clean the plunger and plunger sleeve.
8) The needle valve of the fuel injector is stuck. The solution is to remove the fuel injector and take out the
needle valve of the nozzle for cleaning, or replace the needle valve fitting.
9) The injection time is incorrect. The solution is to readjust the injection time as required.