KVGT issue

PC228USLC-10

PC228USLC-10 Slightly different Than OP but I thought I could use most of the tips and Hints.

Still, all valid info, you are correct.

My pressure seems to be about 15 psi below minimum, is there a way to check the relief valve or will whole pump need to be removed.

You're above 125, yer fine. It's just control pressure to exercise the functions

Biglou101 said: My pressure seems to be about 15 psi below minimum, is there a way to check the relief valve or will whole pump need to be removed. Click to expand... Im glad FWF is here! Do everything he says as he is the resident expert on Komatsu stuff. JohnC. is good info also!

Biglou101 said: Did you ever resolve this issue? We were lead to replace a turbo assembly on the machine and issue is still present, checked oil drive and control pressure. Have 160-180 psi, the vgt is constantly cycling back and forth and the pressure fluctuates. All engine sensors have good readings through Insite. Im leaning toward the EPC for the KVGT but am looking for some input before I continue. Any and all input will be greatly appreciated. Click to expand... Just to chime in...……...is there any current active fault codes on the monitor? It sounds like something else may be going on.

Vetech63 said: Im glad FWF is here! Do everything he says as he is the resident expert on Komatsu stuff. JohnC. is good info also! Click to expand... Oh no, not even close, I'm just a fill in when John C is busy

You can give yourself more credit than that! I know a little about 15 year old stuff. I think you got the new stuff better than my old brain can sort through.

My noggin is stuck in Volvo operating systems. I find it makes it difficult to grasp how Komatsu works and Liebherr for that matter. Slowly coming around though. When it comes to engines and their operating systems, I try really hard to stay current .

With engines, I’m not going to try any more.

you guys are good, typically the screen in the bottom of the rgr housing plugs easily, if its clean and good pressure from the boost oil pump, pull off the epc for vgt control and clean it well, and iirc correctly there is 2 screens under the block with the oil feed line on the tubro, the 125/140 engines plug them all the time. if no change change the turbo, ive changed a few for the helicopter noise your hearing.

Machine came back after working fine for a week, doing the same surge and had a fault for ca2554 exhaust back pressure sensor in range low. Surging again, replaced sensor and cleaned tube to manifold. Code came back for turbo position fault and machine continues to surge.

I don't know if this will help you but I have the same code CA2387. Checked the oil pressure for the EGR valve and KVGT. all of my pressures were good. the position senor for the KVGT was also good. I looked on the monitor and the position for the KVGT would stay at .018 and would not change. I replaced the turbo because the vane plate was stuck. After replacing the turbo machine ran good KVGT valve would stay around .213. The code went away, I ran the machine for 30 min no problem. Got a call the next day for the same code. Looked at the valve and it was stuck on .132 and would not change. I removed the turbo and disassembled. Some debris had gone though the turbo and bent some of the fins so the vanes could not slide though the plate. The engine seems to run to good for a piston or valve be damaged. the machine is on its way back to the shop now. Anyone have any suggestions on what it might be. Anyway maybe this will help you. I apologize if any of the terminology is wrong.

DK88 said: you guys are good, typically the screen in the bottom of the rgr housing plugs easily, if its clean and good pressure from the boost oil pump, pull off the epc for vgt control and clean it well, and iirc correctly there is 2 screens under the block with the oil feed line on the tubro, the 125/140 engines plug them all the time. if no change change the turbo, ive changed a few for the helicopter noise your hearing. Click to expand... my pc210-10 just threw this code. Disassembled turbo and all looks good. Going to try to find screens tomorrow. I've had low boost pressure as long as I've owned it. Komatsu says I should hit 31psi and 26 is best I've seen, normally varies from 15 to 21. I had intercooler pressure tested.

What are you using to measure boost pressure? The onboard electronics?

John C. said: What are you using to measure boost pressure? The onboard electronics? Click to expand... yes, just chosing the custom monitoring in the screen. On the predetermined monitoring I noticed oil switch is off! Is thT for oil pressure or level? How can I turn it back on?

I've taken the turbo apart and cleaned the carbon off of the VGT so insure it is not sticking. I've cleaned the 2 screens in the top of the turbo as well as the on at EGR inlet. I'm seeing vgt positions up to .220 and down to .150 during operation. It indicates .000 when engine is off. If those values are normal then I think I can look elsewhere, if those are not then ill try running pressure check on oil supply. this machine has never boosted over 25psi for the few months I've owned it. Komatsu says it should hit 31psi. anyone else have one of these machines and willing to share their numbers?

The engine will only develop the amount of boost needed to carry the load against it. Have you checked your boom up cycle time? The system is load sensing.

I can go check that. I was maxing out bucket curl to load it. After it throws the code it seems to de-rate and get really weak.