Cat 950gc. Сначала запускался с ручной подкачки. Один крутит, другой качает. Теперь перестал так запускаться, только с эфиром.Стала появляться ошибка «низкое давление в топливной магистрали»…
Please can you post in English. The forum rules require it. Also please include a machine Serial Number.
Ok. I’m sorry.
No problem. Just translate your text above into English and post it up.
Cat 950gc. At first it started with manual pumping. One is spinning, the other is swinging. Now it stopped running like that, only with ether. The error "low pressure in the fuel line" began to appear...
M5K06268 2022.9.2
E398 (2) - Low Fuel Rail Pressure. Troubleshooting is "Fuel Rail Pressure Problem" (see attached). I hope that you have access to Caterpillar ET diagnostic software to assist in your diagnostics, because you are most likely going to need it.
Thank you. There is no access to diagnostic programs. The filters have been replaced, there are no leaks. We assume, and the information you sent confirms our assumptions that it is about the valves. Can you tell me where they are?
Have you performed Step 2 of the troubleshooting procedure to check the electrical connectors J1 & J2 of the engine ECM.? I understand that you do not have ET but you can still check for loose/bent pins & sockets. Also for the presence of condensation or corrosion.
You have changed the filters (Step 3) so Step 4 is to check the function of the rail pressure sensor, even though it is not generating Diagnostic Codes. See attached. You will also require a complete electrical schematic for the machine. Check your message inbox.
Please tell me where the ECM J1/P1 and J2/P2 connectors are located?
The ECM is mounted on the side of the engine.
Is it?
I can't open this file.
That is it. It is an Adobe pdf file. Sometimes they are difficult to open on a smart phone, you need a laptop or PC. It opens fine for me.
I am very grateful to you. We don't have any information about the car at all. We identify and correct malfunctions knowing the principles of operation of the units. This is often ineffective and can lead to more serious breakdowns. How do I access the Caterpillar ET diagnostic software?
The official answer is that you buy it from your local Cat dealer. There is a initial purchase cost plus an annual subscription fee, and the software has a timer built into it so that if you fail to renew the subscription on time it becomes deactivated. Unofficially it is available by other methods. I will let you do the searching........... In order to function ET also requires hardware to connect between a laptop computer and the machine diagnostic port. It is called a Communication Adapter. See this LINK .
Unfortunately, this product will not be delivered to me. Similar ones are sold on our sites. There are no official dealers on our territory. We'll figure it out anyway. With your help, I think we were able to identify the fault. Today those who call themselves service specialists came and we had a dispute with them. They claim that the loss of pressure in the fuel line is due to the fact that the injectors, each of them, are equipped with check valves and some of them are defective (or several) and reset the pressure.
Actually, the very first malfunction, which occurred about three months ago, was that the engine stopped starting on its own, only after manual fuel pumping, while there was a feeling that the fuel did not pass further into the system. After a while, about a month later, after manual pumping, the engine stopped starting, and the lower plastic part of the coarse filter began to be torn off by the pressure created by the pump. We began to use ether to launch. About two weeks ago, a low pressure error began to appear, at first less often, now more often. This error appears when the tractor is in place with the engine running.
The error does not occur during the operation of the tractor. The error does not appear for 7-9 hours (even when the tractor is with the engine running), if after starting 15-25 seconds of revolutions at values of 2000-2200. If this is not done, the error appears within a minute after launch.
We assume that violations in the operation of the injectors would manifest themselves in the operation of the engine, the engine works perfectly, there are no gaps when increasing the speed, there is no black or white smoke, there are no extraneous sounds and vibrations, the oil level is normal from replacement to replacement. The instruction you sent does not contain information that the injectors are involved in the pressure relief in the fuel line. In our opinion, the injectors may be involved in the fact that the engine stopped starting, but then there would be changes in its operation, which would definitely have appeared in three months, and they are not there. We assume that our problem is related to the incorrect operation of the intake valve on the high-pressure pump. We will think about how to check the correctness of its operation without diagnostic equipment.
As far as I know the only product that will work to communicate with a Caterpillar Diagnostic Port is a Cat Communication Adapter. You may possibly find that the "similar one" you speak of might not work.
Nige, thank you for participating in solving our problem and gaining valuable experience. For some reason, only you answer in the topic. Politicians contribute to my education and improvement of my professionalism))) Thanks to them))))))) Can you say something about injectors?
Unfortunately I have no personal experience of the C7.1 engine in your 950GC machine. However what I can say from experience of smaller models of the same series of engines is that they DO NOT like "dirty" fuel. It causes many problems all related to wear in the expensive comnponents of the fuel injection system. For this reason the use of non-Caterpillar fuel filters is not recommended on these engines. As a typical example on a smaller model of C-Series engine (where I do have experience) we would troubleshoot the problem in the foilowing sequence if all other diagnostic procedures failed: - 1. Replace rail pressure relief valve. 2. Replace injectors. 3. Replace HP fuel pump.
We decided to start with injectors. Is every injector equipped with a check valve?
Personally I would have tested the pressure sensor and possibly replaced the rail pressure relief valve first but it is not my decision to make. According to the parts list the rail pressure relief valve is a non-serviceable part. It is part of a "fuel rail assembly" that also includes the rail pressure sensor. See the attachment. I will investigate further and see whether or not separate Part Numbers are available for the relief valve and the pressure sensir, despite what the Parts Manual may say. EDIT: Regarding the above. From another source I found that the rail pressure relief valve is Part Number 398-6226 and the pressure sensor is P/N 375-6988.
Here is a parts list for the exact same 394-9639 Fuel Rail Group taken from a different machine model that shows the serviceable Part Numbers for both the pressure sensor and the pressure relief valve.
Each injector has an internal valve that is opened and closed by the solenoid. In the strictest sense it is not really a check valve.
The information you share with me, Nige, is valuable for our team. We don't have more reliable sources. The tractors we work on (CAT950GC, Komatsu wa430, Deer724k) are very good and strong. That's why we try to take care of them. The replacement of injectors was approved by the head, I think in any case it will be good for the engine. His work is already 7000 hours. And by the way, there is also a question about this: is it worth leaving the old injectors to repair them and leave them in reserve?
Those who call themselves service specialists claim that the low pressure error to the fuel line is caused by the incorrect operation of these valves. I do not agree with them, I refer to the diagnostic algorithm and other information that I receive from you. I will continue the dialogue with the mechanic, because now my arguments, thanks to you, are based on the manufacturer's information.
I think you are right not to agree with them. Attached is some information regarding the operation of the fuel system. I think your engine has both a water separator and a pair of secondary fuel filters. It may not look exactly like the illustrations in the document but the principle of operation is the same. One of the critical factors with these engines is an inspection and drain the water from the water separator every day. The expensive parts of the fuel injection system do not like water...!!
Water, water, water... Interesting... Water damaged the valve... Interesting... And you know, Nige, those who call themselves service specialists, repaired our front axle (their repair is a separate story), after that the hydraulic oil began to get into the bridge, the relief valve on top of the bridge, until that time it never worked and we had to install the crane in the filler plug (I'll send you a photo tomorrow), but then, with an intense load, it was not always possible to stop and release the pressure manually, as a result of which this valve, receiving the load, began to work again. Your information led me to the same idea about the pressure relief valve from the fuel rail... Not working, or working little, or vice versa, working too hard, the valve lost mobility...
that is why we always replaced the rail pressure relief valve as "Step 2" after first making sure that the rail pressure sensor was working correctly.
I have seen that before........ Well not the "fix" but the problem of the small relief valve being covered in debris, seized up, and as a result not relieving pressure. We had a far more elegant fix for the problem. Remove the relief valve and mount it high up inside the front chassis of the machine where it cannot get covered with debris. The illustrations below are from a 988H but serve to illustrate the principle. I cannot guarantee that any of the listed Part Numbers will fit a 950GC machine but it will give you the idea how to modify the axle breather design.
Our mechanic is very slow to repair, so I continue to work on the car and conduct surveillance. So the error about the low pressure in the fuel line manifests itself when the fuel tank is half full. There is no error above this mark. It becomes even more interesting. Is this due to the fact that the tractor does not start on its own, only with the ether? Looks like I'll have to look in the fuel tank...
I would blow compressed air through all the fuel lines plus disassemble the head assemblies for both the water separator and the secondary fuel filter to check that none of the internal passages are plugged with debris. If the machine works fine with a full tank of fuel the possibility also exists of a crack or pinhole in the fuel suction tube inside the tank.
Nige, since only you communicate with me on this topic, I have a question about the front axle. Can I ask it here or create a new topic???
I would suggest to make it a separate thread. It may be for the same machine but it is nothing related to the engine.
I continue to exploit and observe. There were suspicions that one of us tried to drain the fuel with a hose through the filler neck and damaged something inside with the hose. Such an opportunity cannot be ruled out, the colleague does not admit it. Maybe you have a diagram of the location of the fuel intake parts inside the tank? It seems to me that there were problems with the readings of the device on the panel. I paid attention to them to suspicion. The device as a whole shows correctly, but it does it jerkily and not smoothly as before...
Problems with translation. I apologize. I paid attention to the device before suspicions of a colleague arose.
There is no clear information regarding the inside of the fuel tanl. See the attached which is all the information available. All I can suggest is to remove the tank, open it up and take a look. It may benefit from a thorough internal cleaning anyway. I do not think you have anything to lose at this point.
Thank you, Nige. With your help, we have collected a lot of useful information. The mechanic promises to start repairs the other day.
Hello colleagues!!! The problem has been solved. The nozzles were replaced and all the questions were over. I TAK YOU TO everyone who participated and helped to gain useful experience!
Still, sometimes the engine starts for a long time, as if the fuel leaves the low-pressure system. It looks like we'll examine the fuel tank...