L3400HST won't start after fuel line bleeding

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
Yesterday while getting ready to mow, the tractor suddenly stalled. I got it run but it stalled again. The same happened a couple more times. A friend helped me troubleshooting the problem and he said the fuel filter was really dirty, so we removed the filter reservoir and drained it. There were little brown particles/spots on the filter. The filter reservoir was automatically filled as soon as we screwed it back on. After a few tries, I got the tractor running again but then suddenly it stalled. This time I noticed a short puff of white smoke coming out on the right side of the engine. The PTO was not on during all this time. Today I installed a new fuel filter but the tractor would not run. I bled the fuel line as outlined in the operator's manual: opened the air vent cock while cranking the starter for 20-30 seconds, then closed the air vent cock just before I stopped cranking. I repeated this bleeding procedure 3 more times but no luck. Engine turned over good but would not run. I will do the injector line bleed this weekend, following the video posted in this forum. In the mean time can you tell me or guess what caused that puff of white smoke and where it might come from. What is fuel solenoid, as it was discussed in one post. BTW the tank was almost full. I would appreciate very much any recommendations that you might have.
 

North Idaho Wolfman

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Your tractor has an active solenoid, that means it needs to work for it to run.
When you turn on the key you should hear a click come from the front right side, that's the solenoid engaging, it will allow fuel to pass to the injectors.
If your not hearing a sound or if it get hot to the touch then there is probably your fault in the system.
You can remove the solenoid and all the inside plunger parts to test, when removed it should run, pull the manual shut off to kill the engine (right side red knob).

Don't worry about the white smoke it's just un-burnt fuel, like a backfire on a gas engine.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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There is no red knob to kill the engine on this L3400, or at least I never saw one. Can you send the link of the diagram so I study it more. Thank you Wolfman.
 

North Idaho Wolfman

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Yea know what your right nadda on the manual override.
To shut it off just push in on part 90 threw the hole, this is only a test run don't run it without the solenoid in place as dirt will get in the motor.
I'm not sure if a relay runs this solenoid, if you have a test light make sure it's getting power when the key is on.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
Today I bled the air at the injector lines by loosening the nuts and lines- there was no fuel coming out at all at these spots. My thoughts were either the fuel stop solenoid was stuck in the off position or there was no juice coming to the solenoid. My friend would try to hear the click of the solenoid when I turned the key to the on position - no click and no feel of any movement with his hand on the solenoid. BTW all my fuses were checked good. I removed the wire connector from the fuel stop solenoid and measure the voltages between each of the 2 terminals of the connector with the body (ground) with a multi-meter - there was zero voltage. So either the wiring harness or the main ignition switch is faulty. How do I go about testing the main switch and the wiring harness? Your suggestions are appreciated.
 

North Idaho Wolfman

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I'll have to do some research on your solenoid, it might be that both terminals are hot and ground is the body, or do you see on wire going to ground?
If one wire goes to ground jump the other to the battery and you should hear the solenoid kick in.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
Wolfman, I did not see any wire going to ground from the solenoid. What I did was remove the wire from the solenoid. This wire comes from the ignition switch. There are 2 terminals on the connector plug of this wire. I then checked the voltage between each terminal and ground when key at ON position - zero voltage. Is the switch bad? How do I test it? Thanks.
 

North Idaho Wolfman

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It could be that it's delivered power from the opc (occupancy computer) and not directly from the switch, or it could be delivered from a relay.
You need to get the WSM for your tractor and it will have a wiring diagram and a trouble shooting flow chart.
Because your tractor has a computer it can do some major damage just jumping power randomly, or testing with a test light.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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Virginia
I just tested the ignition switch and it is fine. The man at the Kubota Parts said I should check the relay and all fuses.
I removed the instrument panel to look for the relay, there was nothing there, just wires coming together into a bigger bundle. All fuses in the little box near the clutch are fine (checked with multi-meter.)
Then I located 2 black boxes next to the battery on the left side. One box labeled Main 40A Key Stop 30A; the other box labeled Key Switch 40A. The 30A fuse in the Key Stop was blown. The other 2 fuses are fine. Got a new 30A fuse put in. I asked my son to turn the key to ON as I sat close to the fuel solenoid to listen as well as putting my hand on the solenoid: NO CLICK. The engine cranked but would not start.
Back to square one. What I need to do next?
Wolfman: I believe the 2 terminals on the fuel stop solenoid are both hot and ground is the body.

According to Kubota parts list & diagrams website, the stop solenoid relay is located somewhere between the fuel tank and the instrument panel.
http://www.kubota.com/part/partsList.aspx
 
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North Idaho Wolfman

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Go back and check the fuse and make sure it didn't blow again, if it did, replace and pull the solenoid because it's bad.

If it didn't lets test the solenoid with the meter, check ohms from body to each pin and then across both pins.

The fuse is after the relay there for, It's very unlikely the relay is blowing the fuse, I'm betting you have a bad solenoid.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
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I finally got it running. The cause was the poor contact between the plug and the solenoid terminals. But the trouble shooting process is very interesting and lengthy before I got to this point. I really appreciated all the help I received from the forum especially from Wolfman.

As of yesterday after I replaced the blown 30A fuse in the Key Stop box near the battery, I got power to the stop solenoid wire. Tractor would crank but not start, thinking the solenoid is bad and needs to be replaced. I removed the solenoid from the tractor and called one dealer near me to see if the could test the solenoid and if it's bad I would have to buy a new one. I was told that the solenoid has to be tested while on the tractor. Called another dealer, the tech told me to bring it in. He put the power from the portable battery to each terminal of the solenoid, the shaft jumped quickly - the solenoid works fine. They told me to start the tractor without the solenoid. That's what I did- tractor started immediately, so the fuel pump, injection pump work fine, and no air in the system. That pointed the cause to the connection at the solenoid. I scraped, sanded the terminals of both the plug and solenoid, squirted some WD40 Rust Release then cleaned for good measure. The tractor started immediately.
I felt so good.
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
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Excellent to hear!!! :cool:

For a long term fix, pull the plug and take some white lithium grease give it a good amount in the plug reconnect wipe off the extra grease.

It will keep the air and water out and keep the connection good.
 

Tooljunkie

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May 13, 2014
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While lithium grease works, if you have silicone grease that would work also.
As wolfman mentioned, keeping air/ moisture off electrical connectors keeps them from corroding.

Good you got it sorted out, and posting your solution will certainly help someone else.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
61
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Virginia
I still have erratic starting problem due to the unpredictable/inconsistent electrical contact at the fuel solenoid connector plug. I had to remove the plug then reconnect and with some jiggling, etc. for the fuel solenoid to engage (with the click sound.) With the winter and snow season around the corner, I am thinking about replacing the connector wire and plug. But I can't see where to the wire is connected to, since the wire was joined with other wires inside a black plastic tube. I've looked at the electrical wiring diagram on the Kubota Parts list but it's impossible to tell where the wire goes. Can someone help me with this? I'd like to replace the wire and plug all together. Many thanks.
 

Hai

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Kubota L3400 HST
Mar 2, 2014
61
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Virginia
I called one dealer then went to see another dealer with the photo of the plug with the hope that I can buy the connector plug for the fuel solenoid. They both said Kubota does not sell plug. The first dealer said the plug is a part of the electrical harness, and that costs $700+. So today I cut off the plug and bought 3/16 insulated, crimp-on quick connects from Radio Shack. I even taped electric tape around the metal parts of the quick connects for extra insulation. The connection was tight. So far so good, it clicked and started each time. The only time the solenoid did not click was when I turned the key to start immediately right after I just turned it off. Does the relay have something to do with this? What is the function of fuel solenoid relay? Thanks.
 

Stubbyie

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Jul 1, 2010
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Those plugs are common in form although you may have to do a bit of looking to find the 'one' that fits. Try Allied or Newark or Mouser Electronics catalogs--hardcopy might be better--for hundreds of different style connectors.

For what it's worth, in my humid foggy part of the world electrical tape alone just creates pockets for moisture to accumulate and corrode connections.

Try cleaning the connectors, painting with fingernail polish in multiple coats, then wrapping tightly with electricians self-bonding silicone-based splicing tape. Tape when stretched and overlayed sticks together and forms a solid mass. Can't then be unwrapped; has to be gently cut apart. But is effectively water tight. I use this stuff in downhole waterwell wiring splices (in addition to heat shrink).

Which if you choose to use--heat shrink tube--be sure to use the double-layer or interior adhesive mastic-coated type: truly waterproof if correctly applied by heating gently from the center of the splice toward the ends until a [usually] clear or white bubble of adhesive forms at each end of the tube.

Please post back your experiences so we may all learn.
 

Tooljunkie

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If there are wires connected directly to solenoid, then a connector, cut off both ends and either hard wire or splice in a generic type connector.
Hard wiring / solder and heat shrink would be the most failure proof, but if the solenoid ever needs to be replaced it will be a chore.
 

coachgeo

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Autopart stores and RadioShack sells liquid electrical tape. This is I assume basically liquid plastic. Create your connection. Poor alchohol on it to remove any moisture too maybe? Make sure electricity flows thru it. Then coat the shiat out of it. Should keep it dry and clean with it completely sealed. You will have to burn off the coating to get back into it.
 

Hai

New member

Equipment
Kubota L3400 HST
Mar 2, 2014
61
0
0
Virginia
If there are wires connected directly to solenoid, then a connector, cut off both ends and either hard wire or splice in a generic type connector.
Hard wiring / solder and heat shrink would be the most failure proof, but if the solenoid ever needs to be replaced it will be a chore.
I thought I had the problem fixed. The tractor started fine this morning and I did not drive it anywhere. But in the afternoon, no fuel solenoid click and no start. Next week I will solder the 2 wires to the solenoid and try to heat shrink the connections for protection. In the meantime I'll be looking for the plug - see the attached pics. If you see this type of plug anywhere, please let me know. Many thanks.
 

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