2020 McCormick Tractor DPF regen issues

   / 2020 McCormick Tractor DPF regen issues #1  


New member
Mar 22, 2023
2021 X1.35 McCormick
I have a 2020 X.135 with the Kukje engine. It has 250 hours on it. I know in the beginning, I was not doing what I was supposed to do by keeping it at a higher idle. I had performed a few regens on it and never had an issue.
However, this winter, it started to "de-rate" itself for any use, PTO, or just driving up a hill. I contacted my dealer, and more than once, they suggested that I try to perform a regen. I had tried, but the highest I could get it to idle up to was 1500-1800 rpms(even on warm days). After several hours of running the tractor at its highest rpm level, and nothing was changing, they then recommended taking the DPF filter off, and having it "Baked." I did that and reinstalled the DPF filter, and it is still doing the same thing. The only difference now is there is a DPF warning light on now that was not on previously, as well as an engine warning light. I still can not keep it idled high enough or long enough to perform a regen. NOW WHAT should I try?
   / 2020 McCormick Tractor DPF regen issues #2  
With the Kukje engine, since it's mechanically injected engine, there is no ECM and therefore it can't really derate itself. What usually happens when a DPF clogs too much is that the engine will start knocking very loud along with not getting up to RPM very easily.

The impression I get from your description is that you may actually have a fuel delivery issue or an air filter issue. When was the last time you checked or changed the fuel filter? And the air filter? I would start there.

Also, this may or may not be helpful but that tractor is actually a Branson 3725, if I recall correctly.
   / 2020 McCormick Tractor DPF regen issues #3  
Correct. The dealer didn't know the engine well... Its a non ECM motor, it doesn't derate. It was never the DPF
   / 2020 McCormick Tractor DPF regen issues
  • Thread Starter
Thank you for the reply. I will change out the fuel filter and air filter.
They were changed at the last service, which was around 200 hours. Let me try to describe what I am referring to as de-rating better. On the initial start, with no problems after running for 3-4 minutes, I will increase the RPM to 1000, wait another few minutes and then take it to max RPM, which used to be around 2800. It will stay at 2800 for 30 seconds, maybe, then start to decrease RPM, first going down to 2000, then after two more minutes, it will barely be at 1500 RPM. This occurs while idling if I were to drive the tractor to grade the driveway, I would have to keep it in a low gear and only run between 1200-1500 RPMs with the throttle lever in the max position if it is in an incline even less. These issues started around the 242-hour mark, and I am now around 255, but most of the hours have been trying to get it to go into a regen. Thanks again for the information!
   / 2020 McCormick Tractor DPF regen issues #6  
Another issue could be a clogged fuel tank vent. The vent on these tractors is built in on the fuel cap. You may want to take a peek on that as well and even try running it with the fuel cap loose so it can vent freely and see if it still does the same thing.

Also, can you tell if the electric fuel pump is running? With the ignition on ( without the engine running), you should be able to hear the pump running which is just a clicking sound really fast.
   / 2020 McCormick Tractor DPF regen issues
  • Thread Starter
I checked the fuel cap and also loosened it, but no real difference in what it had been doing.
I can hear the fuel pump running without the engine running also.
I made two videos which I will try to add them later, to help hear the drop in RPMs.
   / 2020 McCormick Tractor DPF regen issues
  • Thread Starter
I think I am sending it to the dealers for repair. I have tried all of the suggestions, and I still have the same issues. If it is a fuel delivery issue, I don't understand how it can start out idling great, but after a few minutes, it gradually decreases in power even quicker when put into a strain. I will post the results from the dealer's mechanic. Thanks for your help.