5 Tips Injector Common Fault Analysis

From: http://www.sinocmpinjector.com/
In the process of using the injector, it is inevitable that some faults will be encountered. As a dealer or maintenance master, if you can know some common faults of fuel injectors which are not only the embodiment of your professional ability, but also the embodiment of increasing customer trust. Let us introduce the five common faults of the injector.

Injector common fault analysis:
Failure case one
Fault phenomenon:
The owner of the car reported that the engine was heavily smoky and the vehicle was underpowered.

Exclusion step
1) After checking the diagnostics, there is no problem appeared.
2) There is no problem in checking the gas path.
3) So we decided to do the "broken cylinder test",
4) It is found that the injector of the engine is not working properly.
5) The injectors are turned off one after the other, and the displayed engine speeds are too different.
6) Decided to dismantle the injector
7) After the injector was pulled down, it was found that the injector was also heavily carbonized.
8) And there is a piece of white spot on the fuel injector head.
9) There is a serious problem with the fuel added to the car.
10) Causes serious carbon deposits, and water in the fuel causes white spots on the injector head.

Solution:
Clean up the charcoal and install the injector. The car emits black smoke.

Failure case two
Fault phenomenon:
1) The same owner reflects that the engine is seriously smoky. After the vehicle is stopped, the vehicle cannot start and cannot start.
2) However, after inspection, it was found that the airway was unblocked, and the rail pressure at the start of inspection was found to be only 160 Bar.
3) It is suspected that the injector leaks oil and causes pressure relief.
4) Immediately check the injector to find that the 2-cylinder injector has a large amount of oil return.
5) Making sure the injector is damaged.
6) Replace the 2-cylinder injector for troubleshooting.
7) Disassemble the injector and find that there are no copper washers.

Failure case three
Fault phenomenon:
1) The same engine emits black smoke with a maximum speed of 1500 rpm.
2) According to the driver, everything is normal when the car is bought back.
3) After using it for more than a month
4) There is a strong smoke in the engine during idle and acceleration.
5) Report the failure at the same time:
6) The oil metering unit current exceeds the upper threshold
7) Failure of the pressure limiting valve to open
8) The error code can be cleared,
9) The engine can run normally for a while after the flash code is cleared.
10) It is normal to observe the change of the current value of the oil metering unit, and the oil metering unit is tested normally.
11) It is stated that the oil quantity measuring unit is normal, and the current value overrun is not caused by the oil quantity measuring unit itself, but is caused by the external oil circuit.
12) Check the oil inlet and return oil of the low pressure and high pressure oil lines, where there are leaks and blockages.
13) Now the problem is concentrated in the middle of the injector, which is not working properly.
14) Do the acceleration test. Now the engine speed after the 4th cylinder is broken, which is more than 60 turns higher than the other cylinders, indicating that the fourth cylinder work is indeed problematic.
15) Remove the 4th cylinder injector and find that it has been burned with the water jacket, the water jacket and the injector have been deformed, and the cylinder head and injector are replaced after normal.
16) Pull out the injector and find that the copper washer on the front of the oil head is gone. I don't know if it’s burnt or missing.
17) After replacing the 4th cylinder injector, the problem is solved.

Failure case four
Fault phenomenon: The car owner reports that the car is weak and emits black smoke.
Failure analysis
1) Using the diagnostic instrument to detect, the engine has no fault flash code, it may be a mechanical fault. The single-cylinder test is performed with the diagnostic instrument. The engine can not meet the test conditions, so the cylinder can only be manually broken. There is no obvious change after the test. After the removal, it was found that the oil head had rust, which could be judged to be due to the presence of water in the diesel fuel.
2) The fault is that the oil is unqualified, and there is water in the oil, which causes the injector needle to be stuck, causing the injector to bleed or not spray.
Only the engine is unable to smoke black smoke.

Failure case five
Symptoms: The speed can only be maintained at 1500 rpm. The fault code P0699 is interpreted as: “The sensor power supply voltage 3 in the ECU is higher than the upper limit”; P100E is interpreted as: “the pressure reducing valve is open”; P100F is interpreted as: “Fault Pressure shock rail pressure limiting valve request".
Inspection process: The car is a bus with running mileage of 14,000 kilometers. According to the power supply 3, the rail pressure sensor and the power supply of the throttle 1 are provided, and the two sensors are inspected. After checking, it is found that the voltage of the accelerator pedal signal 1 is too high, and the fault is eliminated after the wiring harness is replaced.
Fault analysis: Since the accelerator pedal and the rail pressure sensor are both powered by “power supply 3”, when the accelerator pedal signal line is shorted to the power supply or to the ground, the supply voltage of the rail pressure sensor is affected, which causes the system to misidentify that the system has insufficient oil pressure. The oil is continuously supplied to the rails, causing the oil pressure to be too high and the pressure limiting valve to open.
The above description is a brief introduction to the five major common failures to fuel injectors. Other injector related articles will be updated afterwards. If you want to know more about injectors, you can leave a message below this article and we will get back to you as soon as possible. Finally, thanks for your reading.
From: http://www.sinocmpinjector.com/

7 Tips You Need to Know Before Purchasing the ISUZU 4HK1 Injectors

From: http://www.sinocmpinjector.com

The ISUZU 4HK1 fuel injector is one of the precise parts of the 4HK1 diesel engine. The injector is particularly vulnerable to get damage due to wear and overpressure. The 4hk1 engine is the widely use of in Case, Hitachi and other machinery equipment, which is in particularly large demand. Because of the demand, the fuel injectors in the market will pass away the sham as the genuine. We need to pay special attention to the following tips when we buy 4HK1 fuel injectors of ISUZU engine parts.

1.Original or Refurbished?

The 4hk1 injectors are generally from ISUZU and Denso factor  y. If you buy it from the original agent in low quantity, the injectors from both would be particularly expensive. But there are refurbished injectors. So the original and the refurbished products coexist at the same time in the market. Before your payment, you should think carefully and make a choice, buy the original or the refurbished injector.

2. Is the refurbished injector in bad quality? 

In general, the quality of refurbished products will be relatively lower compared with the original products. But in fact, the work life of a refurbished injector will last about 80 to 90 percent of the original one. If the refurbished manufacturer’s production technique meets the original requirements, it is generally possible that the refurbished injector can achieve standard quality.

3.Package can trick you.

Although we mentioned that manufacturers with better manufacturing technique would be able to bring the refurbished injectors up to standard quality. However, because of different manufacturers, the quality of injectors is uneven. And it is a great damage to the interests of customers that many refurbished injectors are originally packaged and in the market. Therefore, it is necessary to cooperate with big brand suppliers in long-term relationship.

4. Are 4HK1 Fuel Injector and 6HK1 Fuel Injector in common use?

Yes, the fuel injectors of the 4HK1 and the 6HK1 engines are in common use.

5. Please pay attention to the item number.

As we said above, both ISUZU and Denso suppliers provide 4HK1 fuel injectors, but there are many parts numbers of them. The parts number of Isuzu fuel injector is like x-xxxxxxxx-x, and the parts number of Denso fuel injector is xxxxxx-xxxx. During purchasing, it is necessary to make sure the corresponding part number in order to buy product of correct part number.

6. Can I exchange the old broken injector with the new one?

SINOCMP provides replacement activities for old injectors. We will make quotations based on the quality of the injectors we received. We accept the old broken injector in exchange for the refurbished one. But the original injector will not participate in the exchange activity.

7. Do I need to embed the code with ID?

The pure original parts have the code setting, which aims to make ID code information recognized and learned by ECU, and then accurately master injection flow of fuel injector and other specific parameters, so as to achieve accurate matching effect. That is done from a professional perspective, which requires a series of detection equipment setting. However, the original injector and ECM will be self-matching during installation, which aims to master the appropriate injection state. So we do not need to set the ID code. The fuel injector also can be installed and used directly because original injector factory will make the fuel injector set for calibration to ensure that it can be used.

Special tips: The electric fuel injector has higher requirements on oil. So we should use fuel oil in good quality; Fuel filters must also be checked and replaced regularly to avoid clogging the oil circuit with impurities and affecting the precision of the injector.

10 Tips Common Injector Faults and Removement Methods

From: http://www.sinocmpinjector.com/

The Bosch common rail injector is the precise coupling of the diesel engine system. The working condition of the injector directly affects the power, economy and reliability of the diesel engine. From the working principle of the injector, it is not difficult to see that the injector needs to have a certain injection pressure, injection process and appropriate cone angle. In addition, the injector should be able to quickly cut off the fuel supply when it needs to stop the injection. No oil dripping.

In the working process of the injector, there will be a variety of faults and phenomena, so what are the common troubleshooting ideas and methods of the injector?

1. The Orifice is Blocked.

Because solid impurity particles are mixed in the fuel, or carbon deposits are generated due to poor combustion, the working time will be a little longer, and the injection hole will be semi blocked. Once the injection hole is blocked, the fuel supply pressure of the injection pump will rise with a knocking sound.

Prevention methods: on the one hand, the fuel entering the injector shall be strictly filtered; on the other hand, the combustion shall be improved to prevent the injection hole from being blocked due to excessive carbon deposition.

2. Spray Nozzle Dripping

When the injector is working, the sealing cone of the needle valve body will be frequently impacted by the needle valve. In addition, the high-pressure fuel is continuously injected from this place, the cone will gradually appear wear or spots, which will cause the injector to drip oil. When the temperature of diesel engine is low, the exhaust pipe emits white smoke, and when the temperature of diesel engine rises, it becomes black smoke. The exhaust pipe will emit irregular shooting sound. At this time, if the oil supply to the cylinder is stopped, the smoke exhaust and firing sound will disappear.

Troubleshooting: remove the nozzle, check whether the movement of the needle valve is flexible and whether the sealing of the seat surface is good, and then carefully clean and research or replace the new nozzle coupling.

3. Nozzle Corrosion and End Carbon Deposition

The corrosion of spray nozzle is caused by the cold corrosion caused by sulfide in exhaust gas. The corrosion of spray nozzle is caused by the cold metal surface, so it is subject to chemical corrosion. All nozzles found to be corroded shall be replaced.

Carbon deposition at the end of the nozzle is easy to form when the diesel engine is running at idle speed or under low load. When the load of the diesel engine increases, the carbon slag on the fuel injector will be burned when the fuel is injected. The carbon deposition at the end has a certain impact on fuel atomization and fuel distribution uniformity during combustion, resulting in incomplete combustion, power reduction of diesel engine, post combustion and various mechanical failures.

Troubleshooting: remove the nozzle and remove the carbon deposit on the nozzle by mechanical or weak corrosion. It is very important to remove the carbon deposit inside the spray hole, but the sealing seat surface must be protected from damage. In order to prevent the steel wire for cleaning from breaking in the hole, the steel wire must be installed in the chuck, and the length of the steel wire exposed to the spray hole shall not exceed 2 mm.

4. Needle Valve Stuck

The water or acid substance in the diesel oil will rust the needle valve and get stuck. After the sealing cone of the needle valve is damaged, the combustible gas in the cylinder will also rush into the mating surface to form carbon deposits, which will cause the needle valve to bite, and the injector will lose the injection effect, causing the cylinder to stop working.

Troubleshooting: remove the fuel injector, take out the fuel injector coupling, and use tools to pull out the needle valve. If it is not easy to pull out, put the fuel injector coupling into the diesel oil and heat it for about 20 minutes before taking it out. When taking out the needle valve, the tail is padded with copper skin, and the tail is clamped with pliers and pulled out while rotating. Pull it out and put it into the cleaning solution for cleaning, and then refill it. If it is the invasion of dirt, it will be flexible after cleaning. If it is due to the geometric shape of the coupling parts that affects the flexibility, a small amount of grinding paste should be added for light grinding, and cleaning should be carried out after grinding.

5. Poor Atomization of Fuel Injector

When the injection pressure is too low, there is carbon deposit in the nozzle wear, the end face of the spring wear or the spring force drops, it will cause the injector to open in advance, delay to close, and form the phenomenon of poor atomization. The diesel engine power drops, the exhaust gas emits black smoke, and the machine operation sound is abnormal. In addition, because the diesel droplets with too large particle size can’t be fully burned, they will flow into the oil pan along the cylinder wall, which will increase the oil level, reduce the viscosity and worsen the lubrication, and may also cause the accident of tile burning and cylinder pulling. At this time, the fuel injector shall be disassembled for cleaning, maintenance and re commissioning.

6. Broken Spring

In addition to the permanent deformation caused by the decrease of the rigidity of the pressure regulating spring of the injector, the fracture of the spring is also frequent, which has become one of the weak links of the injector. It is mainly caused by the poor fatigue strength of spring steel under high temperature, high load and high frequency working conditions.

Solution: improve the fatigue strength, select high-quality heat and fatigue resistant materials, and carry out surface treatment and shot peening to enhance the fatigue strength. In order to make the pressure regulating spring work safely and reliably, reduce the dynamic load of the spring, the fuel injector can be designed as the spring can be immersed in the diesel oil in the fuel injector body. So that when the fuel injector is working, the working ring of the spring can produce hydraulic “buffer” and some lubrication effects, so as to prevent the spring from breaking due to the formation of pitting surface on the contact surface.

7. The End Face of Needle Valve Body is Worn.

The end face of the needle valve body is impacted by the frequent reciprocating motion of the needle valve, which will gradually form a pit over a long period of time, thus increasing the lift of the needle valve and affecting the normal operation of the injector. The needle valve body can be clamped on the grinder to grind the end surface, and then the fine grinding paste can be used to grind the glass plate.

8. The Guide Surface of Needle Valve and Needle Valve Hole is Worn.

The frequent reciprocating movement of the needle valve in the needle valve hole, together with the invasion of impurities in diesel oil, will make the guide surface of the needle valve hole wear gradually, so the gap increases or there are scratch marks, resulting in the increase of the internal leakage of the injector, the decrease of the pressure, the decrease of the injection quantity, the delay of the injection time, and the difficulty of starting the diesel engine. When the injection time is delayed too much, the diesel engine can’t even run. At this time, the needle valve coupling should be replaced.

9. The Joint Hole Between the Injector and the Cylinder Head Ieaks and leaks Oil.

When the fuel injector is installed in the cylinder head, the carbon deposit in the installation hole shall be carefully removed, and the copper gasket must be flat and shall not be replaced by asbestos plate or other materials to prevent poor heat dissipation or failure to play a sealing role. If the copper washer is made by ourselves, it must be processed with red copper according to the specified thickness to ensure that the distance between the injector and the cylinder head plane meets the technical requirements. In addition, when the pressure plate of the fuel injector is installed firmly, unilateral bias shall be avoided, and it shall be tightened evenly according to the specified torque, otherwise the head of the fuel injector will suffer from gas leakage and oil channeling due to deformation and deflection.

10. The Fuel Injector Return Pipe is Damaged.

When the wear of needle valve couple is serious or the fit between needle valve body and injector shell is not tight enough, the return oil quantity of injector increases obviously, some of which can reach 0.1-0.3kg/h. If the oil return pipe is damaged or leaked, the oil return will be lost, resulting in waste. Therefore, the oil return pipe must be intact and sealed so that the oil can flow into the oil tank smoothly. If the return pipe is connected to the diesel filter, a check valve shall be set at its terminal to prevent the diesel in the filter from flowing back into the injector.

From: http://www.sinocmpinjector.com