L3901HST tractor no start.

[Phil P]

Hello all

Here is the problem.

Model L391HST S/N 97805

Owner states replaced battery and tractor started and ran for a few minuets and died. Now cranks but doesn't run.

The following was performed.

Verified battery had 12.6V battery.
With the ignition on the fuel pump was not turning on.
Verified no power to the electrical connector.
Tested MAF sensor electrical connector which shared the same power connector.
no power to pin 1 on MAF sensor.
Removed the meter panel trim to gain access to the engine ECU.
Found power present to cavity F & H terminals.
supplying 12V with power probe to Terminal E and was able to get the fuel pump to turn on.
Found ECU Was not supplying ground to terminal G.

Any ideas as to what needs to be done here to make engine run?

Is there a way to extract codes from the ECU?

Phil P

 

[mehma]

Hello all

Here is the problem.

Model L391HST S/N 97805

Owner states replaced battery and tractor started and ran for a few minuets and died. Now cranks but doesn't run.

The following was performed.

Verified battery had 12.6V battery.
With the ignition on the fuel pump was not turning on.
Verified no power to the electrical connector.
Tested MAF sensor electrical connector which shared the same power connector.
no power to pin 1 on MAF sensor.
Removed the meter panel trim to gain access to the engine ECU.
Found power present to cavity F & H terminals.
supplying 12V with power probe to Terminal E and was able to get the fuel pump to turn on.
Found ECU Was not supplying ground to terminal G.

Any ideas as to what needs to be done here to make engine run?

Is there a way to extract codes from the ECU?

Phil P

I’d be checking the ECU power and ground circuits before condemning the ECU itself. Since applying 12V to terminal E makes the fuel pump run, that suggests the pump and at least part of the circuit are OK, while the ECU isn’t completing the expected control circuit at terminal G.

I’d also check all ECU grounds, ignition-switched power, fuses/relays, and the relevant interlock/immobilizer inputs. A wiring diagram and pinout for the L391HST would be very helpful here. If the ECU is capable of storing fault codes, there should normally be a diagnostic connector or manufacturer-specific procedure/tool to retrieve them.

 

[TheOldHokie]

Hello all

Here is the problem.

Model L391HST S/N 97805

Owner states replaced battery and tractor started and ran for a few minuets and died. Now cranks but doesn't run.

The following was performed.

Verified battery had 12.6V battery.
With the ignition on the fuel pump was not turning on.
Verified no power to the electrical connector.
Tested MAF sensor electrical connector which shared the same power connector.
no power to pin 1 on MAF sensor.
Removed the meter panel trim to gain access to the engine ECU.
Found power present to cavity F & H terminals.
supplying 12V with power probe to Terminal E and was able to get the fuel pump to turn on.
Found ECU Was not supplying ground to terminal G.

Any ideas as to what needs to be done here to make engine run?

Is there a way to extract codes from the ECU?

Phil P

Have you eliminated the safety interlock systems?

Dan

 

[ayak]

Any chance the new battery was installed with the negative cable first (and the ECU then got zapped)?

 

[Phil P]

Thank you all

mehma

You and I think a like. Now my question is where would the data port be? Or is there a way to display codes on the panel ETC.

Where do I go to disconnect to disable the safety system for testing purposes?

TheOldHoke

Do you have any idea how to do that or where the switches would be?

I had a problem at this same ranch with a zero turn mower that a friend of theirs had installed a $160 starter and it still did t start I replace a $28 solenoid to fix it. LOL

ayak

Very possible the 2 persons that did that are not maintenance personnel in that case a $4,000.00 ECU would be the answer.

How ever my experience with this type of unit is when the ECU has been torched it wont do anything.


Again I thank all of you and my responses are not intended to be derogatory or smart ass I just seem to have a way about me that leads people to mistake my intentions.

I am just an 84 year old redneck

Phil P


Just got informational.

The trouble codes can be displayed on the instrument panel.

E-93 and P0606

 

[BAP]

Here is a link to the Workshop Manual for free.

https://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor%20Owners%20Manuals/&file=L3301%20L3901%20L4701%20WSM.pdf

 

[TheOldHokie]

Thank you all

mehma

You and I think a like. Now my question is where would the data port be? Or is there a way to display codes on the panel ETC.

Where do I go to disconnect to disable the safety system for testing purposes?

TheOldHoke

Do you have any idea how to do that or where the switches would be?

I had a problem at this same ranch with a zero turn mower that a friend of theirs had installed a $160 starter and it still did t start I replace a $28 solenoid to fix it. LOL

ayak

Very possible the 2 persons that did that are not maintenance personnel in that case a $4,000.00 ECU would be the answer.

How ever my experience with this type of unit is when the ECU has been torched it wont do anything.


Again I thank all of you and my responses are not intended to be derogatory or smart ass I just seem to have a way about me that leads people to mistake my intentions.

I am just an 84 year old redneck

Phil P

For the interlock system start with obtaining and reading the workshop manual.

I dont know where the diagnostic port is but your dealer does and they are about the only place with the diagnostic hardwsre and software needed to use it.

Dan

 

[re54drider]

For the interlock system start with obtaining and reading the workshop manual.

I dont know where the diagnostic port is but your dealer does and they are about the only place with the diagnostic hardwsre and software needed to use it.

Dan

Pardon me chiming in but the OP stated that it would crank but not start. My L2800 will not crank if a safety switch is not working. Have you checked for fuel delivery? That is where I would start.

 

[TheOldHokie]

Pardon me chiming in but the OP stated that it would crank but not start. My L2800 will not crank if a safety switch is not working. Have you checked for fuel delivery? That is where I would start.

Pardon me but I acttually own a L3901 and I dont lnow if there is a safety interlock condition that will let it crank but not start. I can't rule it out. Can you?

The L3901 has a computer controlled high pressure common rail engine. How would you propose checking for fuel delivery or injector operation?

My suggestion is simply rule out the easy thngs before jumping into the complexities of the engine. But what do I know?

Dan

 

[re54drider]

Pardon me but I acttually own a L3901 and I dont lnow if there is a safety interlock condition that will let it crank but not start. I can't rule it out. Can you?

The L3901 has a computer controlled high pressure common rail engine. How would you propose checking for fuel delivery or injector operation?

My suggestion is simply rule out the easy thngs before jumping into the complexities of the engine. But what do I know?

Dan

I did not mean to step on any toes. I base my comments on my experience with a 2007 L2800. Please forgive me for offering another possible option.

 

[re54drider]

Pardon me but I acttually own a L3901 and I dont lnow if there is a safety interlock condition that will let it crank but not start. I can't rule it out. Can you?

The L3901 has a computer controlled high pressure common rail engine. How would you propose checking for fuel delivery or injector operation?

My suggestion is simply rule out the easy thngs before jumping into the complexities of the engine. But what do I know?

Dan

"Pardon me but I actually own a L3901 and I don't know if there is a safety interlock condition that will let it crank but not start I can't rule it out. Can you?"

Yes I can. If you leave your PTO on or the tractor in gear will the starter engage? Mine will not.

 

[whitetiger]

TSB-2023-035-E-R3

Issue: The engine may fail to start, and DTC code P0605 or P0606 may appear.

Solution: If DTC P0605 is present, replace the engine ECU with the updated engine ECU per the Workshop Manual and complete a manual DPF regeneration per the Diagnosis Manual.

If only DTC P0606 is present, update the ECU Software to the latest software and clear the DTC codes

 

[TheOldHokie]

I did not mean to step on any toes. I base my comments on my experience with a 2007 L2800. Please forgive me for offering another possible option.

My apologies for my tone. The L3901 is nothing like the L2800. Blindly diving into the high pressure fuel delivery system is not for amateurs.

Whitetiger just posted a response detailing a known ECU issue that can produce the crank - no start symptoms. He has posted it before and as a L3901 owner I should have remembered.

I am not 100% sure but the DTCs he identifies can probably be read from the instrument panel using the procedures documented in the Operator and Workshop manuals. Both are available as free downloads fron kubotabooks.com

Dan

 

[Phil P]

Please hold on on your comments.

I have 65 years experience working on high pressure injection system from the old GM 2 stroke to turbine aircraft engines.

I don’t mined being reminded of procedures for checking things out that I should be aware of because me and every one that works on this type of equipment will skip some obvious things and a reminder may save some time.

Read my post.

I stated the electric lift pump docent run at any time but will run if a ground is provided by probing the ground terminal to ground.

Common sense would confirm if the lift pump is not supplying fuel to the high pressure pump then there would not be fuel pressure to the common rail.

My next comment is to the people here that are old school like me to be very careful of checking fuel pressures on a common rail system.

The later model diesels like this one operate on fuel pressures at the common rail that are quite high up in the thousands of ponds and very dangerous to do the old way we did by loosing a fitting in the injection system to see if there is pressure is dangerous.

I have been informed by people that have had serious injuries trying this method of checking common rail pressure.

My experience is from maintaining the late model JD tractors now that JD provides electronic access to there shop manuals for a very reasonable price per tractor I have access to the information need to avoid checking pressure manually.

Now I have a question should be easy to answer.

I have found that the trouble codes displayed on the panel are addressed by a service bullion from Kubota for this model tractor.

Can any one here tell me how to get a copy of that service bullion?

Phil P

 

[TheOldHokie]

Please hold on on your comments.

I have 65 years experience working on high pressure injection system from the old GM 2 stroke to turbine aircraft engines.

I don’t mined being reminded of procedures for checking things out that I should be aware of because me and every one that works on this type of equipment will skip some obvious things and a reminder may save some time.

Read my post.

I stated the electric lift pump docent run at any time but will run if a ground is provided by probing the ground terminal to ground.

Common sense would confirm if the lift pump is not supplying fuel to the high pressure pump then there would not be fuel pressure to the common rail.

My next comment is to the people here that are old school like me to be very careful of checking fuel pressures on a common rail system.

The later model diesels like this one operate on fuel pressures at the common rail that are quite high up in the thousands of ponds and very dangerous to do the old way we did by loosing a fitting in the injection system to see if there is pressure is dangerous.

I have been informed by people that have had serious injuries trying this method of checking common rail pressure.

My experience is from maintaining the late model JD tractors now that JD provides electronic access to there shop manuals for a very reasonable price per tractor I have access to the information need to avoid checking pressure manually.

Now I have a question should be easy to answer.

I have found that the trouble codes displayed on the panel are addressed by a service bullion from Kubota for this model tractor.

Can any one here tell me how to get a copy of that service bullion?

Phil P

My spologies - I missed the fuel pump part of your post.

Contact a Kubota dealer for the service bulletin if its different thsn what Wjitetiger posted.

The Kubota diagnostics are expensive and availability lsrgely limited to authorized dealers, third party service prividers, and large fleet managers.

Dan

 

[re54drider]

My apologies for my tone. The L3901 is nothing like the L2800. Blindly diving into the high pressure fuel delivery system is not for amateurs.

Whitetiger just posted a response detailing a known ECU issue that can produce the crank - no start symptoms. He has posted it before and as a L3901 owner I should have remembered.

I am not 100% sure but the DTCs he identifies can probably be read from the instrument panel using the procedures documented in the Operator and Workshop manuals. Both are available as free downloads fron kubotabooks.com

Dan

This post makes me glad I bought my tractor before the new restrictive rules kicked in. I am learning that computers can cause all sorts of problems.

 

[TheOldHokie]

This post makes me glad I bought my tractor before the new restrictive rules kicked in. I am learning that computers can cause all sorts of problems.

Its a double edged sword. Computers also give you greatly improved performance. Just look at the difference in efficiency abd power in todays automoble engines vs the 80s.

Dan