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8 reasons and maintenance methods for diesel generator engine not working

2021-12-16Font scaling:

     The engine of a diesel generator set cannot start normally is a typical engine operation problem. The reasons include the first use of the new engine, long-term unused use, long-term operation of the unit, and component wear.In this article, we will explain the problem in detail, introduce the possible reasons why the engine cannot start normally, and provide users with reliable solutions.

     1. The fuel quality does not meet the requirements

     The use of incorrect grades of fuel or excessive impurities and water content in the fuel will cause the engine to fail to start normally. Therefore, we should first ensure that the engine uses qualified fuel.

     2. The generator starter does not work

     Cause of failure:The engine can start, but it doesn't work.

     Repair method:

     1>The starter is intact, and the wiring connection is firm and not loose. (Figure 1)

                      (Picture 1: Location of starter)

     2> The start control relay can operate normally, and the circuit is intact and not loose. (Picture 2)

             (Picture 2: Location of start control relay)

     3> The stop switch should be in the off state. (If it is in the open state, it should be rotated as shown by the arrow to make it bounce back to close) (Figure 3)

                      (Picture 3: Stop switch position)

     3. Battery power is too low

     Cause of failure: Insufficient battery power of diesel generator set can cause difficulty in starting or failure to start.The positive electrode of the battery is used to judge the electric spark splashed by the ground flashover. If the spark is weak, it is considered that the battery is insufficient. 

     Repair method:

     It is recommended to replace the battery or charge it. (Figure 4)

         (Picture 4: Huaquan generator set uses camel battery)

     4. The electronic control system of the diesel generator cannot be powered on

     Cause of failure:When the fault indicator does not light up during the power-on self-test, or the diagnostic instrument cannot be connected, the electronic control system cannot be powered on.

     Repair method:

     Check the harness and insurance of the electric control system (as shown in Figure 5), the power switch (as shown in Figure 6), especially the ignition switch.

                             (Picture 5: Control system harness)

                                      (Figure 6: Power switch)

     5. Diesel generator high pressure oil pump failure

     Cause of failure:

     There is a blockage inside the high-pressure oil pump, the high-pressure oil pump plunger is worn, and the overflow valve in the high-pressure oil pump is blocked or stuck, which means that the oil pump cannot suck oil.

     Repair method:

     Clean or replace the high-pressure oil pump. Replace clean fuel. You can directly contact the manufacturer for repair. (Figure 7)

 (Figure 7: The location of the oil pump and the location of the oil inlet)

     6. Failure of low-pressure oil circuit of diesel generator

     Cause of failure:

     No fuel supply, insufficient fuel supply, unstable fuel supply and air leakage in the low-pressure oil circuit of diesel engines (Figure 8)

 (Figure 8: Many lines before entering the oil pump are all low pressure)

     Repair method:

     1> Make sure there is enough diesel in the fuel tank

     2>Exhaust the air in the low-pressure oil circuit (as shown in Figure 9)

               (Picture 9: Location of exhaust valve and plug cover)

     The exhaust method is:

     Open the plug on the pipe, manually press the exhaust valve, and repeatedly exhaust the air.

     3>Tighten the pipes and joints and the hoses and joints are not squeezed or damaged, etc.

     4>Each filter is not blocked or damaged

     5>The fuel tank vent pipe is not blocked. Some of the oil tanks of the unit do not come with them, and most of the vent pipes are located above or on the side of the oil tank.

     6>The oil pump and filter inlet and return pipelines are connected properly. (Figure 10)

              (Picture 10: Correctly enter and exit the oil circuit)

     7. Diesel engine cylinder air tightness and compression performance failure

     Cause of failure:

     Insufficient compression pressure, excessive wear of piston rings, and air valve leakage.

     Repair method:

     1>Tighten the screws, remove the carbon deposits in the combustion chamber or replace the cylinder. (Figure 11)

       (Figure 11: The combustion chamber is full of carbon deposits)

     There are many ways to remove carbon deposits:

     The most common is the mechanical method that uses wire brushes, scrapers, bamboo chips, gauze, etc. to remove carbon deposits, but this method is low in efficiency and poor in quality.Use chemical solvents (carburizers) to soften the carbon deposits on the surface of the parts. This method has high efficiency and good carbon removal effect, and the surface of the parts is not easy to damage.

     2>Replace piston ring, add cylinder liner as appropriate

     3>Check the valve clearance, the airtightness of the valve spring, valve guide and valve seat. If the sealing is not good, the valve seat should be ground. (Figure 12)

(Figure 12: Piston rings, valve springs and ducts, and valve seats are all inside the cylinder)

       (Figure 12: Schematic diagram of the inside of the cylinder)

     8. There is a fault code in the ECU memory (this method is suitable for inspection and maintenance at the repair station) (Figure 14)

                                 (Figure 14: Location of ECU)

     1>The fault code can be read through the diagnostic instrument (as shown in Figure 15)

     Check and repair related parts or systems according to the fault flashing code information.

                    (Figure 15: Diagnostic instrument)

     2>The fault information of the electronic control system can be read through the CAN instrument. After maintenance, use the diagnostic instrument to delete the historical fault information, and fully run the engine to confirm that there is no fault code in the ECU memory


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