Kubota B3350 tractor regeneration problems

[RickB]

The Feds are a long ways away from pursuing off-roading end user emissions violators. They are not yet serious about the onroad violators.r

 

[LouNY]

Those algorithms are driven by the information the sensors send to the ECM are normally differential pressure across a DPF or DOC and it will also look at several temperatures.
If a filter has low or no differential pressure there would not be a command to perform the algorithm.
Most diesels will not attempt a regeneration without sensors values indicating a need for it, that system seems to try and do a passive regeneration just using high rpm to produce the required temperatures to burn the DPF and it is not getting results confirming completion. The electronic injected engines do so by adding fuel into the exhaust system, many by opening and engine injector during the exhaust stroke of the engine.

 

[SDT]

The Feds are a long ways away from pursuing off-roading end user emissions violators. They are not yet serious about the onroad violators.r

Agreed, Rick, but they are relentless.

 

[SDT]

Those algorithms are driven by the information the sensors send to the ECM are normally differential pressure across a DPF or DOC and it will also look at several temperatures.
If a filter has low or no differential pressure there would not be a command to perform the algorithm.
Most diesels will not attempt a regeneration without sensors values indicating a need for it, that system seems to try and do a passive regeneration just using high rpm to produce the required temperatures to burn the DPF and it is not getting results confirming completion. The electronic injected engines do so by adding fuel into the exhaust system, many by opening and engine injector during the exhaust stroke of the engine.

The regeneration system used on the B3350 and similar engines in some F series mowers is unlike that used in any other Kubota engine. It operates open loop. There is a device in the exhaust system called a reformer. The reformer is essentially a burner that injects fuel into the exhaust to raise the temperature during the regeneration process.

It is my understanding that the ECM bases regeneration timing upon operational history. Yes, there are temperature sensors in the DPF but I am unaware of any differential pressure sensors.

SDT

 

[SDT]

The regeneration system used on the B3350 and similar engines in some F series mowers is unlike that used in any other Kubota engine. It operates open loop. There is a device in the exhaust system called a reformer. The reformer is essentially a burner that injects fuel into the exhaust to raise the temperature during the regeneration process.

It is my understanding that the ECM bases regeneration timing upon operational history. Yes, there are temperature sensors in the DPF but I am unaware of any differential pressure sensors.

SDT

More info.

Local dealer has two more machines in shop for regen issues due to oil past valve guides/seals. One is a ZD, other is a 3350.

Interestingly, the ZD has differential pressure sensors in the DPF whereas the 3350 does not. Both have 3 OT sensors in the DPF.

Apparently, the ZD system measures differential pressure in the DPF whereas the 3350 system measures pressure in the reformer vis a vis atmosphere. Go figure.

Both systems exhibit the same issues.

SDT

 

[JimR]

I went back and read most of the previous posts and is is interesting that the 3350 has the same similar problems as my Kioti NX4510HST exhibits. One thing I caught was the oil going by the valves. I noticed oil film in the pipe going from my turbo to the intake. My dealer said that is normal and sent me pictures of the same black film from another Kioti tractor. Maybe that is the problem with mine. Maybe it is leaking oil by the valves. The dealer told me that they do not know where to go from here on my tractor in regards to what is causing my DPF regen issues. Today I messaged him about getting Kioti to replace my #2 injector that is spewing 50% more fuel into the cylinder. He previously told me that they and the Kioti rep didn't think that was enough fuel to be causing the problem that I am having. UHH, WTF, it is pushing 50% more fuel. That is a problem, replace it. I also sent a message to the Kioti customer service rep. requesting all of the service bulletins for my tractor since it was built and I gave him the serial number . That was yesterday, no reply from him or the dealer about changing the bad injector. I guess that I am on the sh-t list. I feel like a huge lemon belongs on my tractor hood.

 

[JimR]

More info.

Local dealer has two more machines in shop for regen issues due to oil past valve guides/seals. One is a ZD, other is a 3350.

Interestingly, the ZD has differential pressure sensors in the DPF whereas the 3350 does not. Both have 3 OT sensors in the DPF.

Apparently, the ZD system measures differential pressure in the DPF whereas the 3350 system measures pressure in the reformer vis a vis atmosphere. Go figure.

Both systems exhibit the same issues.

SDT

Do you know if the sensors are plugging up with soot?

 

[SDT]

Do you know if the sensors are plugging up with soot?

They are not.

The OT conditions are being caused by over fueling, which Kubota claims is caused by small amounts of oil getting past the valve seals.

Hard to believe but Kubota claims that only a small amount of oil causes OT shutdown.

Thanks, feds.

SDT

 

[JimR]

They are not.

The OT conditions are being caused by over fueling, which Kubota claims is caused by small amounts of oil getting past the valve seals.

Hard to believe but Kubota claims that only a small amount of oil causes OT shutdown.

Thanks, feds.

SDT

I guess if one of my injectors was squirting 50% more fuel then it would cause the same problem. I am talking about a 45HP Kioti. I don't think that matters as these tractors are all based on the same type of system.

 

[SDT]

I guess if one of my injectors was squirting 50% more fuel then it would cause the same problem. I am talking about a 45HP Kioti. I don't think that matters as these tractors are all based on the same type of system.

Unfamiliar with the Kioti system but one of the things that Kubota did to my 3350 before authorizing removal/repair of the cylinder head, etc., was to send out the injectors and injection pump to verify that all was within spec. It was.

SDT