L3400 HST fuel solenoid problem

Lanny Landram

New member

Equipment
Kubota L3400 purchased 2010
Sep 26, 2021
4
1
1
73533
I have an issue with my 2010 L3400 when starting. If you turn the key to start from the off position, it will start and immediately die. If you do not turn the key completely off and try to start it will not start and solenoid will not click. Starts and dies anytime you start from the off position. When key is turned on, you hear a click from the solenoid followed by a second click and no start. Only starts if you go immediately from stop to start position, then dies. I'm not showing 12 v power on either of the two leads but my test leads may not be engaging far enough. Since it clicks, I assume I'm getting some power to pull the coil in. Can someone enlighten me on what's happening here????
 

Dave_eng

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Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
5,235
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Williamstown Ontario Canada
The following is from memory but is generally correct. Each machine has slightly different system and it gets confusing if I do not have the time to study the manuals

Your engine stop solenoid has two internal coils. A strong Pull In coil powered when the key is in the START position and a weaker coil controlled by the safety switches and OPERATOR PRESENCE CONTROLLER (OPC))

Forum L3400 OPC.jpg


Study the info on the OPC on the attached page.

Step one is to check for blown fuse. Step two is for a safety switch which is out of adjustment, wires pulled off or broken.
Owners' manuals typically have a page telling you how to check for the correct operation of the safety switches. I do not nhave a L3400 Owners manual
Dave
 

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Lanny Landram

New member

Equipment
Kubota L3400 purchased 2010
Sep 26, 2021
4
1
1
73533
The following is from memory but is generally correct. Each machine has slightly different system and it gets confusing if I do not have the time to study the manuals

Your engine stop solenoid has two internal coils. A strong Pull In coil powered when the key is in the START position and a weaker coil controlled by the safety switches and OPERATOR PRESENCE CONTROLLER (OPC))

View attachment 66767

Study the info on the OPC on the attached page.

Step one is to check for blown fuse. Step two is for a safety switch which is out of adjustment, wires pulled off or broken.
Owners' manuals typically have a page telling you how to check for the correct operation of the safety switches. I do not nhave a L3400 Owners manual
Dave
Thanks, Dave for the info. I will check it out in the morning. This certainly helps me to understand the circuit.
 

Lanny Landram

New member

Equipment
Kubota L3400 purchased 2010
Sep 26, 2021
4
1
1
73533
Thanks, Dave for the info. I will check it out in the morning. This certainly helps me to understand the circuit.
I"ve taken the fuel solenoid off and checked resistance at 1.5Kohm and 550 ohm. If I hold the pin in and apply 12 v to holding coil, it stays as it should. If I put 12v on other coil, it moves in and out continually. Does not stay in. I've checked out both fuses and they are good. Have 12v on both sides of 2 wire connector when the key is turned on. Tractor will start then die if key is turned from the stop position. Tractor will not start but will crank from the on position. You must turn key completely off and it will start and die every time. Runs about 2 seconds. Hopefully someone has run into this situation before on a L3400 tractor. Sounds like the holding coil is faulty but it will stay pulled in if I put 12 volt on the pin. Any help would be greatly appreciated.
 

PoTreeBoy

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Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
2,795
1,517
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WestTn/NoMs
I"ve taken the fuel solenoid off and checked resistance at 1.5Kohm and 550 ohm. If I hold the pin in and apply 12 v to holding coil, it stays as it should. If I put 12v on other coil, it moves in and out continually. Does not stay in. I've checked out both fuses and they are good. Have 12v on both sides of 2 wire connector when the key is turned on. Tractor will start then die if key is turned from the stop position. Tractor will not start but will crank from the on position. You must turn key completely off and it will start and die every time. Runs about 2 seconds. Hopefully someone has run into this situation before on a L3400 tractor. Sounds like the holding coil is faulty but it will stay pulled in if I put 12 volt on the pin. Any help would be greatly appreciated.
Dave's diagram shows the two pins connected together. I've wondered about this arrangement before. Based on your description, there must be an internal switch in the solenoid, not shown on the schematic, which depowers the pull-in coil at the appropriate time. Sounds to me like your hold coil is ok, but something's wonky in the pull-in.
I'd apply an external 12 volts to both pins simultaneously. If it doesn't pull in, the problem is your solenoid.
 

Lanny Landram

New member

Equipment
Kubota L3400 purchased 2010
Sep 26, 2021
4
1
1
73533
I have read lots of good tips on what to look at but no thread actually pin points the problem with these symptoms. This tractor would start every time from stop position and immediately die. If you tried to start with the key already on it would only crank. If stop solenoid is removed the tractor would start. I changed the stop solenoid but did not fix it. If you check pins coming in to the solenoid and you have12 volt to input coil but no power to the holding coil the problem is with the OPC timer relay. It is responsible for releasing the power from the input coil after starting or energizing the lower voltage holding coil, (not sure which). I did not want to replace this part due to the $90 plus expense but it fixed the tractor. Good as new now. Thanks to all for the info.
 
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