Fuel Rack doesn’t move when ignition is energized.

[Dave 250]

My 7040 has a start issue. The Fuel injet or pump does not open when I turn the key to on position. I opened the inspecation port and notticed I could move it with a screwdriver a little bit and it started immediately. Noe that has ceased to happen. Now it is stuck closed when the solenoid is energized. I removed the solenoid to prove its function and its Perfect, but the rack seems stuck. I lubed it with WD40 but nothing. How do I proceed. The Dealer says I need to remove the Injection Pump and take it to a shop to figure out what’s broken. Any Help would be appreciated. I dont know how to remove the pump. It looks impossible.

 

[Henro]

WD40 is not really a lubricant from what I have read. Perhaps a penetrating oil might be better?

I cannot really answer your question, but can ask one that might contribute something. I have read that removing the fuel lines from the injector pump, the ones that feed fuel to the injectors, can cause issues that are not easy to fix, because something can shift within the pump if this is done.

So my question is, if one does send his pump out for repairs, how does he ensure that nothing shifts when the fuel lines are connected back to the pump?

 

[North Idaho Wolfman]

I dont know how to remove the pump. It looks impossible.

The fuel Solenoid does not directly control the rack.
You need to study the whole workings of this setup before you just randomly remove parts.
This means study the governor and injection pump.
Make sure any parts removed are removed with the knowledge on how to reassemble it properly or it will get really expensive to fix!
I'll send you a link for the WSM (AKA Service manual)

 

[Dave 250]

The fuel Solenoid does not directly control the rack.
You need to study the whole workings of this setup before you just randomly remove parts.
This means study the governor and injection pump.
Make sure any parts removed are removed with the knowledge on how to reassemble it properly or it will get really expensive to fix!
I'll send you a link for the WSM (AKA Service manual)

Thank You Wolfman, I haven’t removed any parts other than the run solenoid to check it’s travel and replace, once I proved it to be functioning normally. The issue is lies in the Rack Travel. Someone else warned of parts Moving if you Bleed the the injectors… Not sure what he referenced to but I have no clue what he meant. Thats a standard procedure in bleeding an Injector pump to my knowledge.

 

[North Idaho Wolfman]

Study the WSM, it will have the procedure to completely trouble shoot it.

I'll say this, I've only see a handful of stuck or malfunctioning fuel injector racks.
And several were from bad rebuild / installs.

 

[Dave 250]

WD40 is not really a lubricant from what I have read. Perhaps a penetrating oil might be better?

I cannot really answer your question, but can ask one that might contribute something. I have read that removing the fuel lines from the injector pump, the ones that feed fuel to the injectors, can cause issues that are not easy to fix, because something can shift within the pump if this is done.

So my question is, if one does send his pump out for repairs, how does he ensure that nothing shifts when the fuel lines are connected back to the pump?

Thank you sir for your input. But not certain how much experience you have with Diesel engines. Cracking the fuel lines to Bleed the injectors is quite common practise on most if not all Diesel Engines. Not sure what you read but find it interesting. I am Quite certain Pumps don’f just Fall Apart or have parts Shift inside if you Bleed the the injector Rack. Just sayin.
Dave 250.

 

[North Idaho Wolfman]

Are you cracking the injector lines at the the pump or injector side?

 

[Dave 250]

Study the WSM, it will have the procedure to completely trouble shoot it.

I'll say this, I've only see a handful of stuck or malfunctioning fuel injector racks.
And several were from bad rebuild / installs.

Some background, My machine has 1402 hrs has been Dealer Maintained since New. Has only been used for holding pallets since new to carry Fruit from the pickers, so Super light duty. Though the Run solenoid Doesn’t control the Rack as you initially commented it actually does control fuel flow to the injectors. It’s the Electrical Shutoff that lets the Rack feed in the first place. If the rack doesn’t open No fuel can flow. So once you know the solenoid is functioning and go to the next thing, is the rack moving to let fuel flow And note the rack does Not move therefore the problem. The question is What can be preventing it from moving to the open position?

 

[Dave 250]

Are you cracking the injector lines at the the pump or injector side?

I Cracked them at the pump. But the problem arose when the engine shut down as if it ran out of fuel.

 

[Dave 250]

I Cracked them at the pump. But the problem arose when the engine shut down as if it ran out of fuel.

Also take note the engine had been getting harder to start for Days before it finally died. I had to turn on the ignition and tickle the rack to make it open, in other words take a screwdriver and lightly push the Rack forward it moved about 1/4” and then the engine would instantly flash.

 

[Dave 250]

So something is binding. And now seems to full on seized. Wierd. To say the least.

 

[North Idaho Wolfman]

The reason I said the fuel solenoid does not control the fuel rack directly, is because the fuel solenoid engages the governor and then that controls the fuel rack.
So an issue with the governor could be your issue.

Any chance that the fuel could have gotten contaminated?

 

[North Idaho Wolfman]

One other possible note, And without more research.
Some model of Kubota Fuel solenoids are dual coil solenoids, they have a pull in coil and a latch coil, if the pull in coil is bad they will not pull in right but the hold coil without any load might pull in on it's own, thus making a simple test not installed look like it's working when it's really not.

 

[Henro]

Thank you sir for your input. But not certain how much experience you have with Diesel engines. Cracking the fuel lines to Bleed the injectors is quite common practise on most if not all Diesel Engines. Not sure what you read but find it interesting. I am Quite certain Pumps don’f just Fall Apart or have parts Shift inside if you Bleed the the injector Rack. Just sayin.
Dave 250.

I realize the fuel lines are cracked at the injectors to bleed air from the system if needed. The point was that at least for some injector pumps something can shift inside the pump if you loosen the lines at the pump improperly. I’m not exactly sure of the mechanism. But I am sure this is a concern at least on some injector pumps. I believe NI Wolfman has commented on this in the past.

Maybe somebody with more knowledge can explain the reason this may be a concern. OR that it is not a concern.

It seems one would want to break the connection at the injector to make sure they bled all the air out of the lines up to the injector. It just seems like cracking the line at the injector pump would not empty air from the line between the pump and the injector.

Edit: I am guessing that is the reason the Wolfman asked where you were cracking the fuel lines in post #7...but obviously that is just a guess...

 

[Henro]

I started a separate thread to ask the question of what the chances are of causing a problem if you cracked the fuel line connections at the injector pump.

Apparently for that to be a problem you have to do more than crack the connection where the injector fuel line hits the injector pump. So I don’t think my suggested possible issue is any issue at all. I did not realize what I had read before indicated that there was two things that needed to be released before an issue would occur.

So simply cracking the fuel lines at the injector pump apparently is not a big deal. If that is all you do… Just wanted to update things as I apparently did not see the total picture.

Still, I think the recommended practice is to crack the fuel lines at the injectors if you want to bleed air out of the system.

 

[Dave 250]

So something is binding. And now seems to full on seized. Wierd. To say the least.

I started a separate thread to ask the question of what the chances are of causing a problem if you cracked the fuel line connections at the injector pump.

Apparently for that to be a problem you have to do more than crack the connection where the injector fuel line hits the injector pump. So I don’t think my suggested possible issue is any issue at all. I did not realize what I had read before indicated that there was two things that needed to be released before an issue would occur.

So simply cracking the fuel lines at the injector pump apparently is not a big deal. If that is all you do… Just wanted to update things as I apparently did not see the total picture.

Still, I think the recommended practice is to crack the fuel lines at the injectors if you want to bleed air out of the system.

Thank you Sir. I appreciate your input. I have 45+ years experience with Diesel Equipment and Still own Too many pieces. Ive done the Bleeding procedure at least a hundred times, never had a problem, it’s not an air lock issue. It something in the Pump. Just looking to see if anyone else has experienced this issue with there Kubota’s.

 

[Dave 250]

One other possible note, And without more research.
Some model of Kubota Fuel solenoids are dual coil solenoids, they have a pull in coil and a latch coil, if the pull in coil is bad they will not pull in right but the hold coil without any load might pull in on it's own, thus making a simple test not installed look like it's working when it's really not.

Thanks Wolfman, this Solenoid is Not Directly connected it is extended when not energized and Retracted when energized. So it’s simply a push to shut fuel off. Nothing More. The Rack is Spring Loaded to open when the Solenoid is energized. In other words it should, under Normal circumstances should Snap open the second the Solenoid is energized.

 

[North Idaho Wolfman]

Your not understanding what I'm saying.
Let me try again

The fuel stop solenoid in that design does not directly effect the rack on the pump.
The fuel solenoid effects the governor and the governor effects the rack.
Thus it might not be an issue with the fuel Injection pump, but a issue with the governor.

But never mind all that:
Pull the fuel injection pump out (all the lines and 6 bolts) ( NOT the whole Fuel pump housing and governor assembly) and check it, that will take about 20min to do.
Then you'll know if the issue is the injection pump or the governor.

 

[Dave 250]

Your not understanding what I'm saying.
Let me try again

The fuel stop solenoid in that design does not directly effect the rack on the pump.
The fuel solenoid effects the governor and the governor effects the rack.
Thus it might not be an issue with the fuel Injection pump, but a issue with the governor.

But never mind all they:
Pull the fuel injection pump out (all the lines and 6 bolts) ( NOT the whole Fuel pump housing and governor assembly) and check it, that will take about 20min to do.
Then you'll know if the issue is the injection pump or the governor.

Thank you