Kubota F3990 Regen Problems

[Lawn Mower Guy]

I am looking for help with the Diesel Regen Technology on my Kubota F3990 that has only 324 hrs, new in 2014, and over those years there have had to be four forced regens by the dealer, two this year, an expensive remedy.

I think the dealer suspects this is my fault because the ECM shows that there have been some instances of the engine being stopped during a regen, which is a no no. He says this bumps the regen up to the next level of severity, and in the end the owner has no choice but to ask for the help of the dealer to do the forced regen.

This has happened twice so far this year even though I have become very vigilant to not allow the engine to stop and also to follow all recommended steps for each stage of the regen [engine at low idle, parking brake on, PTO disengaged etc]. Both times this year the on board system went from the lowest stage with only the regen icon lit up, to the highest stage with the engine warning light flashing, in one jump. That is bizarre.

But the first time the dealer came out to do another forced regen in march he said he could find nothing wrong with the technology. Of course, he is able to disable and to subdue embedded bugs in the technology, do his thing, and then all is well, and he feels vindicated. I do not think that Kubota Regen technology is exonerated.

I call this temperamental technology because it does not come out and shut me down all the time. There have been enough times when I can remember that I have hopped off the machine to unplug the grass chute and the engine has stopped, and nothing else has happened. Why does it only happen sometimes?? Furthermore, can Kubota not design some technology that is able to recover from the engine being shut off and go back to a restore point and continue to do its regen? That is how my home computer works.

Very long story short......I would like to be rid of this technology and delete it from the ECU module. So far I cannot find someone who can do that even though there are enough people who remap ECU's on other machines.

Has anyone out there got any good suggestions for me please?

 

[SDT]

I am looking for help with the Diesel Regen Technology on my Kubota F3990 that has only 324 hrs, new in 2014, and over those years there have had to be four forced regens by the dealer, two this year, an expensive remedy.

I think the dealer suspects this is my fault because the ECM shows that there have been some instances of the engine being stopped during a regen, which is a no no. He says this bumps the regen up to the next level of severity, and in the end the owner has no choice but to ask for the help of the dealer to do the forced regen.

This has happened twice so far this year even though I have become very vigilant to not allow the engine to stop and also to follow all recommended steps for each stage of the regen [engine at low idle, parking brake on, PTO disengaged etc]. Both times this year the on board system went from the lowest stage with only the regen icon lit up, to the highest stage with the engine warning light flashing, in one jump. That is bizarre.

But the first time the dealer came out to do another forced regen in march he said he could find nothing wrong with the technology. Of course, he is able to disable and to subdue embedded bugs in the technology, do his thing, and then all is well, and he feels vindicated. I do not think that Kubota Regen technology is exonerated.

I call this temperamental technology because it does not come out and shut me down all the time. There have been enough times when I can remember that I have hopped off the machine to unplug the grass chute and the engine has stopped, and nothing else has happened. Why does it only happen sometimes?? Furthermore, can Kubota not design some technology that is able to recover from the engine being shut off and go back to a restore point and continue to do its regen? That is how my home computer works.

Very long story short......I would like to be rid of this technology and delete it from the ECU module. So far I cannot find someone who can do that even though there are enough people who remap ECU's on other machines.

Has anyone out there got any good suggestions for me please?

Not familiar with the F3990 model number but suspect that it uses the same four cylinder engine as does the much maligned B3350 tractor. Ignore what follows if it is a three cylinder engine.

2014 is quite early for the engine of which I speak and much has been done to improve the system since then. Later models with all of the updates are much less problematic but the jury is still out.

The first thing to do is to VERIFY that your engine is FULLY up to date. Almost certainly it is not. Get verifiable proof from the Kubota Service representative. You may well not be able to trust your dealer in this regard as many dealers are not competent to perform all upgrades and others do not wish to do so because they make little or no money doing so. Insist upon speaking to the Kubota Service representative if necessary. Do not hesitate as the emissions equipment is warranted for 5 years (IIRC).

If yours is FULLY up to date and you still have recurring issues, insist that Kubota inspect the engine for evidence of engine oil getting past the intake valve seals. My dealer has found 3 or 4 F series engines with this issue. Even a small amount of oil into the engine intake results in a DPF over temperature condition during regen causing immediate engine shut down.

Among other things, the reformer has been updated at least once since 2014. If yours has not been changed within the last 18 month or so, it is not current design. Same with ECU firmware.

Read and understand the regen instructions in your owner's manual and insist upon an up to date manual (and regen decals) if yours is not current. Again changes have been made. Do not allow your dealer to shift the blame to you if you are following the printed instructions that you currently have.

Read the threads herein and, especially, the Orange Forum about the regen issues with the B3350 tractors.

I have a 2018 B3350that now has about 40 hours on it. It exhibited regen issues immediately upon delivery and spent 12 weeks in my dealers shop this summer. Making a long story short, evidence of oil past the intake valves was found. Kubota replaced just about all of the emissions equipment and sent the cylinder head out for remanufacturing. I've had it back for a few weeks now but have not yet used it enough for it to regen, so the jury is still out.

FWIW, the first time mine went back, Kubota denied the warranty claim, claiming "operator error, and my dealer billed me." It was not, of course, operator error and a thorough, well written and persuasive letter to Kubota Customer Satisfaction in Grapevine, TX resulted in this decision being overturned.

Regarding, Kubota's ability to design a workable regeneration system for this engine, this has been done and a replacement is being announced with common rail injection in the imminent October dealer's meeting. Note, the replacements are replacement tractors and mowers. There is currently no plan to retrofit existing machines in the field with the replacement engine.

Much more to this story so I suggest that you read my earlier posts about the B3350 here and on TBN.

SDT

 

[sandyc]

Well written. I bought one of the 3350 exchange tractor and had problems until my dealer performed the specified upgrade. If memory serves, they replaced the alternator with one with twice the power, insulated the blower pipe, installed a new engine side cover, provide a winter front to raise the op temp of the engine, reprogrammed or replaced the ecu, and added decals about removing the fresh air snorkel during snow or below 32 deg. Maybe the reformer was replace....not sure.
The dealer told me that kubota sent and billed them for all the upgrade stuff which costs the dealer about 1200 usd for each 3350 they sold. I’m guessing that if they didn’t upgrade their 3350 tractors the pieces and parts were sold or used for something else.
Since my upgrade I’ve no zero problems. Touch wood

 

[SDT]

Well written. I bought one of the 3350 exchange tractor and had problems until my dealer performed the specified upgrade. If memory serves, they replaced the alternator with one with twice the power, insulated the blower pipe, installed a new engine side cover, provide a winter front to raise the op temp of the engine, reprogrammed or replaced the ecu, and added decals about removing the fresh air snorkel during snow or below 32 deg. Maybe the reformer was replace....not sure.
The dealer told me that kubota sent and billed them for all the upgrade stuff which costs the dealer about 1200 usd for each 3350 they sold. I’m guessing that if they didn’t upgrade their 3350 tractors the pieces and parts were sold or used for something else.
Since my upgrade I’ve no zero problems. Touch wood

My first (declined but subsequently approved) claim was for about $300.

The 12 week sojourn in the shop this summer would have cost somewhere between $6,000 - $7,000 had Kubota not covered it under warranty.

SDT

 

[Jstpssng]

My first (declined but subsequently approved) claim was for about $300.

The 12 week sojourn in the shop this summer would have cost somewhere between $6,000 - $7,000 had Kubota not covered it under warranty.

SDT

I have to ask; were you provided with a substitute while your brand new tractor was down for 12 weeks?

 

[SDT]

I have to ask; were you provided with a substitute while your brand new tractor was down for 12 weeks?

No.

SDT

 

[cold1313]

I have a 2014 F3990 as well, I am the second owner. The original owner had Kubota perform software updates as mentioned below. There should be two buttons for Regen on your dash.
The one on the right must be pressed every time the machine is started. That is how the new program works. This basically tells the machine to regen when required. Not pressing this button (it will stay illuminated) will not allow my machine to regen properly. I'm in the habit now to press it every single time. Don't forget to press it again if you're mowing and shut off the mower for a second.

I've had zero issues with regen.

This has happened twice so far this year even though I have become very vigilant to not allow the engine to stop and also to follow all recommended steps for each stage of the regen [engine at low idle, parking brake on, PTO disengaged etc]. Both times this year the on board system went from the lowest stage with only the regen icon lit up, to the highest stage with the engine warning light flashing, in one jump. That is bizarre.

But the first time the dealer came out to do another forced regen in march he said he could find nothing wrong with the technology. Of course, he is able to disable and to subdue embedded bugs in the technology, do his thing, and then all is well, and he feels vindicated. I do not think that Kubota Regen technology is exonerated.

I call this temperamental technology because it does not come out and shut me down all the time. There have been enough times when I can remember that I have hopped off the machine to unplug the grass chute and the engine has stopped, and nothing else has happened. Why does it only happen sometimes?? Furthermore, can Kubota not design some technology that is able to recover from the engine being shut off and go back to a restore point and continue to do its regen? That is how my home computer works.

I almost always am mowing when the regen occurs. When I've done a parked regen - I am in the same conditions you mention above, however I am all full throttle, to allow the heat to build. Check the manual - but I would not idle the machine. It needs the heat.

If the engine is shutting off when you jump off the machine, you need to set your parking brake so the engine stays running. This will allow the engine to run with you off of the seat. Shutting the engine off while in regen is not good. It cannot just start up where it left off as the program is simple - it's going by the hours and the temperature (basically). The engine and exhaust must be hot enough, and it must run the complete regen cycle. By shutting off in the middle of a cycle, it doesn't know what is going on.

As long as you follow these steps, you will not have any issue with the regen. That's been my experience. As mentioned, I would make sure the ECM has been updated. Also the emissions on this machine is under warranty for 10 years.

If your dealer doesn't agree - find a different one.

 

[alanbNC]

I know this thread is old but I wanted to share this info with you in case you haven't learned of this yet.I work for a small municipality in NC and we have a 2014 F3990 with a front mowing deck that we bought in 2014. Shortly after receiving and using the mower the ReGen system failed and would not function at all. When I returned it to the dealer I was told there was a known issue with those units. Something about the glow plugs in the system that burns off the diesel particulates. They had received a bad batch at the factory and as a result there were a lot of those tractors that had that issue. They kept the unit about two months because the parts were hard to get because of high demand as a result of that issue. They also updated the firmware on the unit. Being that new it was repaired under warranty. Anyway when we got it back it has worked flawlessly ever since. If you search for the Kubota F3990 Regen issue you'll see what I mean. A lot of people complain about issues with that ReGen system. Anyway maybe mention it to your dealer to see what they say if you still have that tractor.

 

[SDT]

I know this thread is old but I wanted to share this info with you in case you haven't learned of this yet.I work for a small municipality in NC and we have a 2014 F3990 with a front mowing deck that we bought in 2014. Shortly after receiving and using the mower the ReGen system failed and would not function at all. When I returned it to the dealer I was told there was a known issue with those units. Something about the glow plugs in the system that burns off the diesel particulates. They had received a bad batch at the factory and as a result there were a lot of those tractors that had that issue. They kept the unit about two months because the parts were hard to get because of high demand as a result of that issue. They also updated the firmware on the unit. Being that new it was repaired under warranty. Anyway when we got it back it has worked flawlessly ever since. If you search for the Kubota F3990 Regen issue you'll see what I mean. A lot of people complain about issues with that ReGen system. Anyway maybe mention it to your dealer to see what they say if you still have that tractor.

The regen issues associated with the engine used in the B3350 and some high end F series mowers and ZTRs (4 cylinder engines) has nothing to do with glow plugs and much to do with reformers.

SDT

 

[RGAZ]

For this thread. If anyone hacks the ECU for a F3990 to allow for "adjustment" of the DPF function please private message me.

Just keeping my fishing line out there....

RGAZ