Can you explain this fuel solenoid problem - L3400HST?

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
When I turned they key to the ON position, I could hear the click from the fuel shut off solenoid, and when the key turned to START, the tractor started fine. But occasionally there was no click from the fuel solenoid, and when key turned to START position, tractor did not run just as expected. I removed the solenoid from its position on the engine and checked its operation. With the wires still connected to the solenoid and the body of the solenoid touching the tractor for ground. The solenoid clicked every time when key turned to ON and then a click when OFF. I repeated this step many times and it never missed a click. But when the solenoid was bolted back on the engine, the solenoid would not produce consistent clicks. Kind of hit and miss. When I did not get a click, I tapped the solenoid lightly with a screwdriver, got a click and the tractor started. The ground connection is good. Sometimes after getting no click, I just let it the tractor sit for a while, then turned the key to ON, got a click and the tractor started fine. Can you explain to me what possibly caused this kind of inconsistency? Does this have something with the replay or the OPC timer, something that I do not understand. Many thanks in advance for your help.
 

85Hokie

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When I turned they key to the ON position, I could hear the click from the fuel shut off solenoid, and when the key turned to START, the tractor started fine. But occasionally there was no click from the fuel solenoid, and when key turned to START position, tractor did not run just as expected. I removed the solenoid from its position on the engine and checked its operation. With the wires still connected to the solenoid and the body of the solenoid touching the tractor for ground. The solenoid clicked every time when key turned to ON and then a click when OFF. I repeated this step many times and it never missed a click. But when the solenoid was bolted back on the engine, the solenoid would not produce consistent clicks. Kind of hit and miss. When I did not get a click, I tapped the solenoid lightly with a screwdriver, got a click and the tractor started. The ground connection is good. Sometimes after getting no click, I just let it the tractor sit for a while, then turned the key to ON, got a click and the tractor started fine. Can you explain to me what possibly caused this kind of inconsistency? Does this have something with the replay or the OPC timer, something that I do not understand. Many thanks in advance for your help.
Based on what you are describing....sounds as if you have a grounding problem, go BACK to the battery, take that terminal off, clean the hell out of the contacts, and replace it, then go and check where the ground cable goes back to the frame, remove clean and replace. Where ever the solenoid makes contact to the motor/frame, clean that too.

Tapping it......there is NOT enough amps to get it moving on the coil inside the solenoid.

Now.....you could have a solenoid that wants to play ......but MOST of the time solenoid works or it doesnt work.......

recheck your grounds and see what happens! and report back, it might be one of those OTHER connections from the timer or something else.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Thanks Hokie for your suggestions. I used the emery (sand) paper to sand until the contacts look shiny and clean. Here are the parts that I sanded: both sides of the solenoid base, the 2 solenoid nuts, the engine surface where the solenoid bolted to, negative and positive battery terminals and cables, and the spot on the frame that the negative cable bolted to. The voltage across the battery is good, almost 13V. Still hit and miss with the solenoid click. Here is my last observation:
When the key is turned to the ON position, and if there is no solenoid click, a light tap with a screwdriver on the solenoid will produce a solenoid click, then key turned to START, the tractor runs. I still cannot figure out what causes this problem... and a light tap to make connection?
 

Jim L.

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Jun 18, 2014
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Condition 1: Tapping the solenoid helps. If this is true, then the solenoid plunger must be hanging. But, you demonstrated that you could make it work all the time, except mounted where it normally would be. So, is it an orientation issue, that is, does the plunger move in the same orientation as it is mounted?

Condition 2: Most likely a ground issue. But, you have cleaned and demonstrated that the connections are good.

Condition 3: Sneak path (or disconnect) around or through the safety circuits. Can be resolved by bypassing all safety circuits with a jumper(s). Diagnostics only, not for operating.

That is all I can think of to fault isolate.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
Jim,
I think your Condition 1 description is the most likely the situation. I do not think the movement of plunger was hindered by something on the engine side, rather something inside the solenoid 'not connected' in order to get the plunger pulled back. So a light tap is needed. But then why it never missed a click when the solenoid was tested unmounted? I really like to find out. Anything else I can try? any other possible causes? Thanks.
 

85Hokie

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Jim,
I think your Condition 1 description is the most likely the situation. I do not think the movement of plunger was hindered by something on the engine side, rather something inside the solenoid 'not connected' in order to get the plunger pulled back. So a light tap is needed. But then why it never missed a click when the solenoid was tested unmounted? I really like to find out. Anything else I can try? any other possible causes? Thanks.

I am with Jim, all points are covered, what does a new solenoid cost..?? (just dawned on me - FUEL solenoid.....thats gonna hurt the check book!)

the fact that is makes NO sound........it could be hung........and the tap is enough to unseat it.....but why in the hand does it work........

off the topic - where you in VA?
 

Jim L.

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Jun 18, 2014
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Texas
You could parallel a 12V LED on the solenoid coil. If the LED is lit, then you have voltage to the solenoid coil. If the LED is unlit, and you tap the solenoid, and coil and LED come on, then you have a path problem.

Same can be done with a voltmeter and a good helper.

The intent is to judge the solenoid good or bad, with no other factors.


I guess that I should ask whether the solenoid has both positive lug and ground lug. Is there a sneak path from the ground lug to the solenoid body?
 
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Hai

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Kubota L3400 HST
Mar 2, 2014
61
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Virginia
You could parallel a 12V LED on the solenoid coil. If the LED is lit, then you have voltage to the solenoid coil. If the LED is unlit, and you tap the solenoid, and coil and LED come on, then you have a path problem.

Same can be done with a voltmeter and a good helper.

The intent is to judge the solenoid good or bad, with no other factors.


I guess that I should ask whether the solenoid has both positive lug and ground lug. Is there a sneak path from the ground lug to the solenoid body?
Thanks Hokie and Jim, the fuel solenoid costs about $170. If the problem is 100% solenoid then I would buy a new unit. The solenoid has 2 positive lugs with the body as ground. Your suggestion of running a parallel 12V LED is excellent. I have a volt meter, maybe I'll do that instead.
I recalled from my previous trouble shooting of this problem, I always had power measured at the end of the wires every time the key turned to ON. But when the wires were reconnected to the solenoid, which was on the engine, then there was hit and miss click.
For now, I'll keep running the tractor for a while and tap the solenoid whenever it does not click. Gather more data. Maybe something else will show up. In the meantime, if anyone in the forum has other ideas or suggestions, please let me know. Thanks.
 

North Idaho Wolfman

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That stop solenoid is a little different than the normal solenoid as it has 2 coils within it, one is the pull in coil and the second is a hold coil.
The click is the coil being pulled in and then if it says in after cranking then the hold coil portion is working.
Use a simple test light to see if and when it's getting power, as a meter might get "hit" with reverse current when the coil collapses, similar to an old cars ignition coil. :eek:
And just as a note, hooking up an LED isn't the best idea, as LED's can not handle that high of reverse current caused by the coil collapsing and would fail after the first de-energizing. ;)
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
That stop solenoid is a little different than the normal solenoid as it has 2 coils within it, one is the pull in coil and the second is a hold coil.
The click is the coil being pulled in and then if it says in after cranking then the hold coil portion is working.
Use a simple test light to see if and when it's getting power, as a meter might get "hit" with reverse current when the coil collapses, similar to an old cars ignition coil. :eek:
And just as a note, hooking up an LED isn't the best idea, as LED's can not handle that high of reverse current caused by the coil collapsing and would fail after the first de-energizing. ;)
That is what I have observed with my solenoid: one click when key to ON and one click when key to OFF.
Wolfman, I do not understand what you said about "might get "hit" with reverse current when the coil collapses, similar to an old cars ignition coil." Can you explain. Also, what is the function of the solenoid relay with respect to the working of the fuel solenoid? Thanks.
 

North Idaho Wolfman

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That is what I have observed with my solenoid: one click when key to ON and one click when key to OFF.
Wolfman, I do not understand what you said about "might get "hit" with reverse current when the coil collapses, similar to an old cars ignition coil." Can you explain. Also, what is the function of the solenoid relay with respect to the working of the fuel solenoid? Thanks.
When you apply power to the stop solenoid, you charge a coil, and when you remove power that charge reverses and comes back on the wire and hit's anything in it's path, it can be seen as a spark where you break the contact.
The relays serves 2 functions, #1 they take a small amperage trigger signal and turn it into a high amperage signal, and #2 most stop and starter solenoid relays have capacitors built into them that absorb the returning charge current from the coil collapsing and reduce or eliminate arcing and eventually damaging the internal contacts.
 

kuboman

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Dec 6, 2009
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I think you have a weak solenoid. The reason it works when out of the machine is that there is no resistance. The coils in solenoids finally do weak after time and yours is just weak enough to be intermittent.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
I think you have a weak solenoid. The reason it works when out of the machine is that there is no resistance. The coils in solenoids finally do weak after time and yours is just weak enough to be intermittent.
I think you are probably right. Right now I'll running the tractor as is and see what else will happen. Today, no tap needed to start the tractor. If all it takes is a tap on the fuel solenoid, I may be able to live with that until it gets worse or when I have had enough. Will report back. Many thanks for all the ideas and suggestions given to me so far.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Well, I had problem again with starting the tractor today. Got a click from the solenoid but nothing happened: no engine turnover. Turned key to OFF and then back to ON, no click. Had to tap several times to finally had the tractor running. I am thinking about doing away with the fuel solenoid for now, at least through the Fall and Winter, and buy a new fuel solenoid next Spring.
Should I cut off the rod of the solenoid and bolt the solenoid on the engine with the wire removed and taped up? and where the rod should it be cut, flush to the surface of the solenoid? Or I can cut a piece of aluminum or heavy plastic and bolt it in place of the solenoid. What are your preferred suggestions? Thanks.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Spring for a new solenoid, it is part of the safety of the tractor!

P/N 1A021-60017 $118.10 Plus shipping
http://www.m-and-d.com/KUB-1A021-60017.html
Thanks Wolfman. Very good price. I am not ready for more work (frustration) if the new solenoid does not solve the problem. That is why I want to delay it until Spring and have the tractor ready for snow clearing of the 400 ft driveway. If I decide to tackle the solenoid now, I'll report back.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
61
0
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Virginia
Spring for a new solenoid, it is part of the safety of the tractor!

P/N 1A021-60017 $118.10 Plus shipping
http://www.m-and-d.com/KUB-1A021-60017.html
Wolfman, according to the Kubota Parts diagram, the part number for the solenoid is either 1A021-60013 or 1A021-60015, depending on the engine serial number. The part that you sent in the link is 1A021-60017. Is this a replacement for both? Thanks.
 

CaveCreekRay

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Late to the party but...

The seat safety switch controls the fuel solenoid doesn't it? That would explain why it will start but then kills right after. I'd bypass that switch before dropping cash on a new solenoid. If that solves the problem, then its the switch. (If that model has one...)

On my 3800HST, there is also a switch on the go-rocker pedal. If it is even slightly out of neutral, with someone out of the seat, it kills the gas via the fuel shutoff solenoid. The pedal hinge points get a little crusty in use and my dealer lubed mine up and its self-centering now. No more quitting every time I get off.

Just one more thing to look at before launching the order.