Kubota D1105 3 cylinder

[Roy Wiggins]

Hello

I hope someone can assist.

I have replaced injectors and serviced injector pump and re-assembled on this 3 cylinder engine, the engine had failed to start hence the overhaul. I Bled fuel to the injector pump successfully, however I can not bleed fuel from beyond the pump and as such the engine will not start.

Fuel cut out solenoid has been renewed and 12v is tested to the solenoid. Turning the engine reveals no fuel from any of the 3 outlets suggesting the restriction is within the pump.

Is there anything I am missing here, or is there a part of the process on this engine I am not aware of?

Many thanks in advance

 

[Nicksacco]

Is it possible that the injector pump rack is "turned off" and thus not pumping fuel?

I think we know the lift pump is working since you have fuel to the injection pump.
When you say you "serviced" the injection pump, I wonder if the fuel shutoff rack is stuck or damaged. (about 2:40 in the video)

 

[pigdoc]

Not sure if the Bosch mini works like the Bosch VE on Dodge Cummins engines, but I have bled the high-pressure lines dozens of times with a Bosch VE.

Basically, crack the nuts loose on the injector ends of all the lines and crank the engine until fuel spurts out around the fittings. Tighten the nuts back down, and away you go.

With a 6BT Cummins, I can get away with bleeding just 3 of the 6 lines - the ones towards the front of the engine, because they're easier to reach!

-Paul

 

[Roy Wiggins]

Is it possible that the injector pump rack is "turned off" and thus not pumping fuel?

I think we know the lift pump is working since you have fuel to the injection pump.
When you say you "serviced" the injection pump, I wonder if the fuel shutoff rack is stuck or damaged. (about 2:40 in the video)

View attachment 87927

The pump was sent to a diesel specialist to clean and check, it got a clean bill of health. The rail moves freely. to the right is stop to the left is open. What I am insure of is the solenoid does not react either in or out when a voltage is applied? The solenoid pushes the rail into the stop position, what I do not understand is how the 'rail' pushes back into the open position - should it be spring loaded?

 

[Roy Wiggins]

Not sure if the Bosch mini works like the Bosch VE on Dodge Cummins engines, but I have bled the high-pressure lines dozens of times with a Bosch VE.

Basically, crack the nuts loose on the injector ends of all the lines and crank the engine until fuel spurts out around the fittings. Tighten the nuts back down, and away you go.

With a 6BT Cummins, I can get away with bleeding just 3 of the 6 lines - the ones towards the front of the engine, because they're easier to reach!

-Paul

I have bled the lines to the supply side of the pump. When the lift pump is operated manually it seems to supply more fuel than when the engine is cranked could low pressure be the fault? When the fuel pump is installed into the block the rail has to be in the stop position before it engages into the block. The fact that the solenoid appears to do nothing when a voltage is applied is a concern. Both the new solenoid and the old one behave this way?

 

[pigdoc]

I have bled the lines to the supply side of the pump. When the lift pump is operated manually it seems to supply more fuel than when the engine is cranked could low pressure be the fault? When the fuel pump is installed into the block the rail has to be in the stop position before it engages into the block. The fact that the solenoid appears to do nothing when a voltage is applied is a concern. Both the new solenoid and the old one behave this way?

I'm guessing you need to bleed the lines FROM the pump to the injectors. It's a simple procedure to loosen the nuts that clamp the ends of the high pressure lines to the injectors, crank the motor to purge the air, and then tighten those nuts back down. You'll know when the lines are full of fuel when it starts spurting from the loosened nuts as you crank the motor.

Air is compressible, so if there is air in the lines, the pulse of fuel from the injector pump will not activate the injector, it will just compress that air. I forget what PSI it takes to activate an injector in that engine but it's a big number, in the neighborhood of 2000 PSI (140 BAR).

-Paul

 

[Nicksacco]

Regarding your other questions:

There should be a spring that closes the "throttle" enough to start and idle.
On my L35 it's connected to the accelerator rod (Grey) which is both foot and hand operated.
In the picture it's location is circled.

The solenoid in this pic is in the unenergized state and the injector pump's rack would be able to pump fuel.

When the "ignition" is switched off, there is a timer that causes 12V to be applied to the solenoid which closes the injection pump's rack. This 12V is applied for 10 seconds at which time the solenoid is de-energized (as this assumes that the engine has stopped).

In the square red line is the place where a manual stop would be (I was working on it at the time). The manual stop is there in case the solenoid or other automatic component fails, the opr can shut down the engine.

(QUOTE) The fact that the solenoid appears to do nothing when a voltage is applied is a concern. Both the new solenoid and the old one behave this way? (ENDQUOTE)
Perhaps the delay timer or fuse has failed.

Let us know what you find

 

[Nicksacco]

One other thing on the solenoid: On mine, the lead from the solenoid looked intact but was internally rotted about midway, thus no worky. All I did was to remove that old lead and solder in a new one. There was nothing wrong with the solenoid itself.

 

[Roy Wiggins]

Regarding your other questions:

There should be a spring that closes the "throttle" enough to start and idle.
On my L35 it's connected to the accelerator rod (Grey) which is both foot and hand operated.
In the picture it's location is circled.

The solenoid in this pic is in the unenergized state and the injector pump's rack would be able to pump fuel.

When the "ignition" is switched off, there is a timer that causes 12V to be applied to the solenoid which closes the injection pump's rack. This 12V is applied for 10 seconds at which time the solenoid is de-energized (as this assumes that the engine has stopped).

In the square red line is the place where a manual stop would be (I was working on it at the time). The manual stop is there in case the solenoid or other automatic component fails, the opr can shut down the engine.

(QUOTE) The fact that the solenoid appears to do nothing when a voltage is applied is a concern. Both the new solenoid and the old one behave this way? (ENDQUOTE)
Perhaps the delay timer or fuse has failed.

Let us know what you find

View attachment 87953

My pump is a little different, I will get a similar photo and post it.

 

[Roy Wiggins]

One other thing on the solenoid: On mine, the lead from the solenoid looked intact but was internally rotted about midway, thus no worky. All I did was to remove that old lead and solder in a new one. There was nothing wrong with the solenoid itself.

Getting a consistent 12v at the end of the leads

 

[Roy Wiggins]

Regarding your other questions:

There should be a spring that closes the "throttle" enough to start and idle.
On my L35 it's connected to the accelerator rod (Grey) which is both foot and hand operated.
In the picture it's location is circled.

The solenoid in this pic is in the unenergized state and the injector pump's rack would be able to pump fuel.

When the "ignition" is switched off, there is a timer that causes 12V to be applied to the solenoid which closes the injection pump's rack. This 12V is applied for 10 seconds at which time the solenoid is de-energized (as this assumes that the engine has stopped).

In the square red line is the place where a manual stop would be (I was working on it at the time). The manual stop is there in case the solenoid or other automatic component fails, the opr can shut down the engine.

(QUOTE) The fact that the solenoid appears to do nothing when a voltage is applied is a concern. Both the new solenoid and the old one behave this way? (ENDQUOTE)
Perhaps the delay timer or fuse has failed.

Let us know what you find

View attachment 87953

Both new and old solenoids behave in the same way. as far as I can tell the solenoid engages with the end of the rack on the pump - pushing the rack would close off any fuel delivery. Will try solenoid for longer to see if it has a timer circuit, which begs the question - could a relay be down?

 

[Roy Wiggins]

I'm guessing you need to bleed the lines FROM the pump to the injectors. It's a simple procedure to loosen the nuts that clamp the ends of the high pressure lines to the injectors, crank the motor to purge the air, and then tighten those nuts back down. You'll know when the lines are full of fuel when it starts spurting from the loosened nuts as you crank the motor.

Air is compressible, so if there is air in the lines, the pulse of fuel from the injector pump will not activate the injector, it will just compress that air. I forget what PSI it takes to activate an injector in that engine but it's a big number, in the neighborhood of 2000 PSI (140 BAR).

-Paul

I can not get fuel to squirt out of the top of the pump, thereby bypassing the fuel lines to the injectors

 

[Roy Wiggins]

Regarding your other questions:

There should be a spring that closes the "throttle" enough to start and idle.
On my L35 it's connected to the accelerator rod (Grey) which is both foot and hand operated.
In the picture it's location is circled.

The solenoid in this pic is in the unenergized state and the injector pump's rack would be able to pump fuel.

When the "ignition" is switched off, there is a timer that causes 12V to be applied to the solenoid which closes the injection pump's rack. This 12V is applied for 10 seconds at which time the solenoid is de-energized (as this assumes that the engine has stopped).

In the square red line is the place where a manual stop would be (I was working on it at the time). The manual stop is there in case the solenoid or other automatic component fails, the opr can shut down the engine.

(QUOTE) The fact that the solenoid appears to do nothing when a voltage is applied is a concern. Both the new solenoid and the old one behave this way? (ENDQUOTE)
Perhaps the delay timer or fuse has failed.

Let us know what you find

View attachment 87953

 

[Nicksacco]

Roy, let me backup for just a second. I think we need to separate two different potential problems:
1) the solenoid
2) the injection pump

Lets address the fuel first:
Why did you have the injection pump rebuilt?

You said; " When the lift pump is operated manually it seems to supply more fuel than when the engine is cranked could low pressure be the fault? "
To operate the lift pump manually what did you do?
Do you have a way to measure the pressure?

if you remove the rubber hose from the lift pump at the injection pump and crank the engine, does fuel spurt out of the hose?

If the left pump is bad, then that could be the issue. You could either replace that pump or simply use an electric one (even temporarily) to see where the issue is.

NEXT:
Is it possible that when you installed the injector pump back into the body, that the governor plate/accelerator plate did not engage the pump rack properly?
Could the rack always be OFF?

Do both the stop lever and the "accelerator" levers work without jamming?
Can you feel the rack being moved when moving the stop lever?

Look at the Stop/Accel plate in the pic. Internally there is a spring to return the lever


SOLENOID:

You said; "Getting a consistent 12v at the end of the leads". Not sure what you mean.
You should only get 12 V TO the solenoid when the key switch is turned off. And the voltage should only last for about 10 seconds. (due to the timer)

If you are getting 12V consistently at the solenoid when the key is turned to ON, then the solenoid is active all the time and that is incorrect. That would mean that the solenoid is shutting off the fuel rack.

Try cranking the engine with the solenoid electric lead unplugged from the solenoid.
If you can crank the engine without the solenoid being mounted to the engine, then that would eliminate something else from the testing.

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[Roy Wiggins]

Roy, let me backup for just a second. I think we need to separate two different potential problems:
1) the solenoid
2) the injection pump

Lets address the fuel first:
Why did you have the injection pump rebuilt?

You said; " When the lift pump is operated manually it seems to supply more fuel than when the engine is cranked could low pressure be the fault? "
To operate the lift pump manually what did you do?
Do you have a way to measure the pressure?

if you remove the rubber hose from the lift pump at the injection pump and crank the engine, does fuel spurt out of the hose?

If the left pump is bad, then that could be the issue. You could either replace that pump or simply use an electric one (even temporarily) to see where the issue is.

NEXT:
Is it possible that when you installed the injector pump back into the body, that the governor plate/accelerator plate did not engage the pump rack properly?
Could the rack always be OFF?

Do both the stop lever and the "accelerator" levers work without jamming?
Can you feel the rack being moved when moving the stop lever?

Look at the Stop/Accel plate in the pic. Internally there is a spring to return the lever


SOLENOID:

You said; "Getting a consistent 12v at the end of the leads". Not sure what you mean.
You should only get 12 V TO the solenoid when the key switch is turned off. And the voltage should only last for about 10 seconds. (due to the timer)

If you are getting 12V consistently at the solenoid when the key is turned to ON, then the solenoid is active all the time and that is incorrect. That would mean that the solenoid is shutting off the fuel rack.

Try cranking the engine with the solenoid electric lead unplugged from the solenoid.
If you can crank the engine without the solenoid being mounted to the engine, then that would eliminate something else from the testing.

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View attachment 88141


View attachment 88140

 

[Roy Wiggins]

I will try what you have suggested tomorrow and report back. I sent the pump away to be checked and injectors to be rebuilt. Engine was running very rough then would not start.

 

[Russell King]

Did you replace the copper seal washer underneath the injector?

Fuel delivery to the injector is the obvious problem that needs to be resolved and you can try to rig up an alternative fuel tank above the injection pump or to the lift pump and see what happens

I am assuming that you bled the air out of the lines to the injection pump

 

[Roy Wiggins]

Did you replace the copper seal washer underneath the injector?

Fuel delivery to the injector is the obvious problem that needs to be resolved and you can try to rig up an alternative fuel tank above the injection pump or to the lift pump and see what happens

I am assuming that you bled the air out of the lines to the injection pump

Yes. fuel flows to the pump but will not flow beyond

 

[Roy Wiggins]

I checked the solenoid voltage. I get 12v when the ignition is ON. when the ignition is off voltage is zero.
The fuel pump does push fuel when the engine is cranked, I have ordered a replacement just in case.

Could there be a relay in the solenoid circuit? Switching ignition on and off does not seem to affect the solenoid (connected to wiring loom but not installed in engine)

 

[PoTreeBoy]

I checked the solenoid voltage. I get 12v when the ignition is ON. when the ignition is off voltage is zero.
The fuel pump does push fuel when the engine is cranked, I have ordered a replacement just in case.

Could there be a relay in the solenoid circuit? Switching ignition on and off does not seem to affect the solenoid (connected to wiring loom but not installed in engine)

I don't think your stop solenoid operates like Nicksacco described it. The L35 has an "energize to stop" solenoid. Kubota uses an "energize to run" arrangement (actually, 2 versions) on most new tractors.

The older version had separately powered "pull-in" and "hold" coils. The pull-in coil was energized when the key was in the start position, and the hold coil was energized anytime the key was on.

The newer version also has two coils, but I think there is an internal switch that de-energizes the pull-in coil when the solenoid core reaches a certain position.

Kubota may have used different setups on different applications. It would help to know what model tractor you're working on.