3 Cylinder Tractor Running Wide Open Only

   / 3 Cylinder Tractor Running Wide Open Only #1  

AndrewCrisp

New member
Joined
Nov 24, 2025
Messages
2
Tractor
2001 JD 430
This is a 2001 jd 430 with a yanmar 3tne84-ejts 3 cylinder and we replaced the leaky o rings on the fuel delivery valves on the injection pump, and now after replacing and putting everything back the tractor will start right up and run wide open with no way to kill it other than to clamp the fuel line shut. It is smoking a bit white when running and it cannot be shutoff with the key, we took the inspection plate off and the rack seems to be moving back and forth freely with the solenoid from the key switch, the throttle lever is moving, but has no effect when the engine’s running. I have read that it may be possible for the plungers to get out of wack when removing the tops of delivery valves but I’m unsure how to address this. I have searched many other forums but have yet to find a solution. Any help would be greatly appreciated.
 
   / 3 Cylinder Tractor Running Wide Open Only #2  
This is a 2001 jd 430 with a yanmar 3tne84-ejts 3 cylinder and we replaced the leaky o rings on the fuel delivery valves on the injection pump, and now after replacing and putting everything back the tractor will start right up and run wide open with no way to kill it other than to clamp the fuel line shut. It is smoking a bit white when running and it cannot be shutoff with the key, we took the inspection plate off and the rack seems to be moving back and forth freely with the solenoid from the key switch, the throttle lever is moving, but has no effect when the engine’s running. I have read that it may be possible for the plungers to get out of wack when removing the tops of delivery valves but I’m unsure how to address this. I have searched many other forums but have yet to find a solution. Any help would be greatly appreciated.
Welcome to TBN! Where are you located? Updating your profile can help folks give you better advice.

As you were replacing o-rings, I would be inclined to suspect that you have air leaking into the fuel line. Do you have any fuel weeps? How hot is the exhaust getting? Any smoke?

Photos might help.

All the best,

Peter
 
   / 3 Cylinder Tractor Running Wide Open Only
  • Thread Starter
#3  
Welcome to TBN! Where are you located? Updating your profile can help folks give you better advice.

As you were replacing o-rings, I would be inclined to suspect that you have air leaking into the fuel line. Do you have any fuel weeps? How hot is the exhaust getting? Any smoke?

Photos might help.

All the best,

Peter
I did my best to tighten everything back down tight, I haven’t noticed any air getting into the lines it’s just getting way too much fuel.
 
   / 3 Cylinder Tractor Running Wide Open Only #4  
Well, I've run into air leaks in a number of diesel engines, and it is usually not pretty. That you were replacing o-rings makes me suspicious, but you are right, something might have gotten knocked while the plungers were being worked on. Is it possible that the lines weren't fully bled of air?

All the best,

Peter
 
   / 3 Cylinder Tractor Running Wide Open Only #5  
Since you have been working on it. Are you sure the throttle is closing all the way? look at and Adj. the idle and see if it lowers the RPM's.
At the linkage and the pump you may even pull the throttle line back and make sure it's closing all the way.
Bleed the air out of the system then you will have a better idea were the problem is. Something sticking in the pump itself?
 
   / 3 Cylinder Tractor Running Wide Open Only #6  
I’m guessing as you are too it’s something wrong with your injection pump. There is a poster with a name something like “thepumpguy” that posts and works on injection pumps. Hopefully he will give you some ideas.
 
   / 3 Cylinder Tractor Running Wide Open Only #7  
I'm sure you've checked it, but could the crankcase be massively overfull, or full of fuel?

EDIT- scratch that. Pinching off the fuel line wouldn't get it to stop that being the case.
 
   / 3 Cylinder Tractor Running Wide Open Only #8  
The truth is being a 2001 jd 430 with a yanmar 3tne84-ejts you may want to post your problem on the JD. forum. Do you have the correct JD. parts Ect.
 
   / 3 Cylinder Tractor Running Wide Open Only #9  
Did u take the pump out of the engine.??
What r u calling the dv orings.?? The top nuts where the steel lines screw on.??
And those r the only orings u replaced.??
By chance did u take the delivery valves out.??
What did u TORQUE the top nuts too.??
 

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