Kubota SVL 90-2 Chugging Under Load

[TektonCNY]

Hey all! I have had this machine now for three years. Bought it with 300 hrs and now just clicked over a 1000. This machine truly has been babied and maintained very well. It gets used for basic construction work in the summer but plows snow in a couple commercial lots in the winter. During this time it痴 been in and out of the dealer shop for a bunch of things some normal some serious. Most of the time it was DPF related issues and finally after 4-5 cleanings was just replaced it within the last 75 hrs. Sensor issues related to oil pressure because something freezes in the dpf/oil system. Temperature problems. All of the, usually throws some kind of code. Now I think the issue at hand is fuel related, but no codes at all. It痴 starts just fine and can idle on high with no noticeable change, but as soon as it drives or actuate any hydraulics the engine bogs down and sputters then recovers and repeat. We had issues in the past with the fuel water separator. We drain it and clean it then usually solves the problem. Not this instance though. So got a union and bypassed the filter hoping the elbows were dirty and again no change. We had the tech out and he said there was erratic flow in the fuel system which was due to the flow control valve. Replaced it and it corrected the readings on the fuel rail, but still skips and sputters under load. The fuel pressure readings are all good and reading as they should. We don稚 think there痴 an issue with gelling because it hasn稚 been cold enough. Even still we致e been adding fuel additive every fill up, and the filter has less than 50 hrs on it. Needless to say we ordered a new one just in case. Should be in tomorrow. The tech says the only thing that can be the problem is the injectors. Now I知 not denying that very well could be the issue, but I take everything the service departments say with grain of salt. I am just continually surprised with the amount of things I have had to replace on a machine with such little hours on it. If you have any light you can shed on this it would be greatly appreciated and if you致e had similar issues please share. Thanks for your help!

 

[rademamj1]

I am surprised the Kubota tech, using his laptop did not check each of the four injectors for your machine while he was onsite. The software can easily identify the status of each injector and determine if any needs replacement. Even just a single bad injector running at 150% output, can overwhelm your DPF/DOC emmissions system with unburned fuel and result in frequent regens and potentially leading to a plugged DPF and frequent cleanings.

I think you have worked hard and are doing right in evaluating potential problems at the fuel end of the system. However, after you replace the fuel filter, and problems still continue, then look hard at those injectors with a Kubota tech. Get the status print out for each injector. Even one bad injector can account for all your problems. Keep us updated on your progress.

 

[RickB]

I am surprised the Kubota tech, using his laptop did not check each of the four injectors for your machine while he was onsite. The software can easily identify the status of each injector and determine if any needs replacement. Even just a single bad injector running at 150% output, can overwhelm your DPF/DOC emmissions system with unburned fuel.

Diagmaster does not have the ability to monitor or display actual fuel delivery rates. An injector over delivering can and will compromise the DPF. I suspect there is one or more faulty injectors There is a very recent bulletin about faulty injectors that may apply to the OP's machine. Recent like within the last couple weeks. Be sure your dealer is aware of it.

 

[MHarryE]

I agree injectors. Computer can’t tell you everything on them. But I thought Kubota uses Denso injectors which in my experience have been the most durable. If so they are on the emissions warranty list if you are still under that. In the past, non-Kubota - I’ve had experience of using non-OEM filters or pre-filling filters taking out common rail injectors quickly.

 

[KWentling]

As I recall Neil Messick had a filter YouTube that said they had lots of SVL fuel issues from owners using non Kubota fuel filters. If you are using non Kubota filters take note.

 

[mikester]

Parking brake on? One of the remotes toggled and nothing connected to it?

 

[rademamj1]

I read again and again the OP's detailed posting of his problem. Repeated DPF issues surely sound like bad injectors. But this loss of power he describes right now, sounds like his Tier4 diesel has gone into limp mode. Experiencing limited hydraulics, unable to build any rpm, and a chugging engine all point to probably limp mode.

I would try to do a manual regen if possible. But I suspect your way past that point, and you now need the laptop to do a forced regen. Once the forced regen is completed, check all injectors because even one bad injector will trigger repeating DPF issues.

I will also encourage the OP to operate his SVL at higher rpm than he normally does, which keeps the exhaust hot and allows for automatic regens. Just my thoughts on this.

 

[TektonCNY]

I am surprised the Kubota tech, using his laptop did not check each of the four injectors for your machine while he was onsite. The software can easily identify the status of each injector and determine if any needs replacement. Even just a single bad injector running at 150% output, can overwhelm your DPF/DOC emmissions system with unburned fuel and result in frequent regens and potentially leading to a plugged DPF and frequent cleanings.

I think you have worked hard and are doing right in evaluating potential problems at the fuel end of the system. However, after you replace the fuel filter, and problems still continue, then look hard at those injectors with a Kubota tech. Get the status print out for each injector. Even one bad injector can account for all your problems. Keep us updated on your progress.

Thank you all for your help. I truly appreciate all the pointers and advice you have given. The tech replaced the fuel control valve because the flow readings were erratic. After he did that nothing changed, so thatç—´ why he decided it was the injectors. The fuel filter came in yesterday and I wanted to try that before the dealer went any further. Glad I did too! Popped it in and everything runs fine! Makes me wonder how many other needless parts I致e paid for...Either way we had a sigh of relief that it was just the Fuel filter. Weæ±*e just not used to be able to fix a problem simply. One final question though. With the fuel filter plugged as it was could the erratic flow readings be caused by the filter instead of the flow control valve?

 

[RickB]

Of course the filter was at fault. Replacing it cured your symptoms. And that should have been the FIRST thing the tech replaced.
The first clue for either you or him should have been the need to repeatedly clean the water separator.

 

[rademamj1]

Glad it all worked out for you, so was just a fuel filter replacement. Keep a couple extra OEM filters on hand. And watch those injectors carefully or you will be replacing the DPF frequently.