Kubota starting but not staying running

[TitanTn]

I have a V2203 diesel generator. I haven't owned it that long, and it ran good when I got it. It recently developed an issue where it starts fine and runs perfectly for up to 2 mins. Then the fuel solenoid shuts it off. If I try and start it immediately, it will attempt, but the fuel solenoid shuts off. If I let it sit for an hour, it'll start just fine and run for a minute or 2 and then the solenoid shuts it off. I've replaced the solenoid, lift pump and temp sensor. Nothing has changed the behavior.

I have also observed that the 12 volts to the solenoid is not being disrupted when the solenoid closes. The solenoid just shuts the motor down and a few seconds later a relay turns off the 12 volts to the solenoid. Something is shutting down the solenoid, but it doesn't to appear to be a lack of 12 volts.

Ideas? Thanks.

 

[JerryMT]

I have a V2203 diesel generator. I haven't owned it that long, and it ran good when I got it. It recently developed an issue where it starts fine and runs perfectly for up to 2 mins. Then the fuel solenoid shuts it off. If I try and start it immediately, it will attempt, but the fuel solenoid shuts off. If I let it sit for an hour, it'll start just fine and run for a minute or 2 and then the solenoid shuts it off. I've replaced the solenoid, lift pump and temp sensor. Nothing has changed the behavior.

I have also observed that the 12 volts to the solenoid is not being disrupted when the solenoid closes. The solenoid just shuts the motor down and a few seconds later a relay turns off the 12 volts to the solenoid. Something is shutting down the solenoid, but it doesn't to appear to be a lack of 12 volts.

Ideas? Thanks.

 

[JerryMT]

I have a V2203 diesel generator. I haven't owned it that long, and it ran good when I got it. It recently developed an issue where it starts fine and runs perfectly for up to 2 mins. Then the fuel solenoid shuts it off. If I try and start it immediately, it will attempt, but the fuel solenoid shuts off. If I let it sit for an hour, it'll start just fine and run for a minute or 2 and then the solenoid shuts it off. I've replaced the solenoid, lift pump and temp sensor. Nothing has changed the behavior.

I have also observed that the 12 volts to the solenoid is not being disrupted when the solenoid closes. The solenoid just shuts the motor down and a few seconds later a relay turns off the 12 volts to the solenoid. Something is shutting down the solenoid, but it doesn't to appear to be a lack of 12 volts.

Ideas? Thanks.

Are you sure the solenoid is shutting it off? Could you have a fuel delivery issue like a clogged line, tank out let, etc. You have enough fuel in the system to start and run without load for a few minutes and then the engine dies Open fuel between the injector pump and whatever the last element in the fuel delivery system is. Are you getting a STEADY, big gush of fuel? If your fuel tank is above the disconnected point you should be. Turn the key so that the lift pump is activated like you are trying to start. Are you getting a big gush of fuel. If you are not then you have a blockage between that point and the fuel tank. When is the last time you changed the filter> You could have crud in the tank blocking the outlet, jamming the filter head, a pinched line, etc Work back toward the tank to find the problem.
Since it's a generator are you using additives like biocides, and things that help water coalesce into the bottom of you fuel filter housing or water seperator? Are you keeeping the tank full to minimize condensation?

 

[TitanTn]

Are you sure the solenoid is shutting it off? Could you have a fuel delivery issue like a clogged line, tank out let, etc. You have enough fuel in the system to start and run without load for a few minutes and then the engine dies Open fuel between the injector pump and whatever the last element in the fuel delivery system is. Are you getting a STEADY, big gush of fuel? If your fuel tank is above the disconnected point you should be. Turn the key so that the lift pump is activated like you are trying to start. Are you getting a big gush of fuel. If you are not then you have a blockage between that point and the fuel tank. When is the last time you changed the filter> You could have crud in the tank blocking the outlet, jamming the filter head, a pinched line, etc Work back toward the tank to find the problem.
Since it's a generator are you using additives like biocides, and things that help water coalesce into the bottom of you fuel filter housing or water seperator? Are you keeeping the tank full to minimize condensation?

All great points. Yes, I'm sure the solenoid is shutting down the engine. I can visibility watch it happen (if I physically hold the solenoid open, it'll run without stopping). The tank is new, fuel lines from the tank to the lift pump are new, and I just changed the fuel filter. I'm pretty sure there's nothing going on from the tank, to the lift pump, through the filter. I'm not sure if I need to start looking at the injector pump (I have no experience at this), but it starts and runs great until the solenoid shuts it off.

 

[PoTreeBoy]

Your description sounds like you have a key stop timer.
Here's a generic diagram:

A loose connection from the keyswitch could cause the timer to energize, shutting your engine down. Otherwise, timer/relay is probably bad.

 

[Matt Ellerbee]

With it being a generator, I’m sure it has many failsafes. Oil pressure or switch maybe?

 

[PoTreeBoy]

With it being a generator, I’m sure it has many failsafes. Oil pressure or switch maybe?

I may have misread the first post. Kubota doesn't seem to use the timer as much now as they once did, probably since the newer equipment has the safety shutdowns and the timer would reduce the shutdown reliability.

 

[JerryMT]

All great points. Yes, I'm sure the solenoid is shutting down the engine. I can visibility watch it happen (if I physically hold the solenoid open, it'll run without stopping). The tank is new, fuel lines from the tank to the lift pump are new, and I just changed the fuel filter. I'm pretty sure there's nothing going on from the tank, to the lift pump, through the filter. I'm not sure if I need to start looking at the injector pump (I have no experience at this), but it starts and runs great until the solenoid shuts it off.

Don't mess with your injector pump (IP) until everything much simpler is eliminated. When you say it will run without stopping if you hold the solenoid open, is that with load on the generator? If the machine can run underload with you manually holding the solenoid actuating rod in the run position, I'd agree that fuel delivery is not the issue. It would also corroborate the IP is OK

Kubota often uses overly complicated control logic on their machines. As the other poster says it maybe a timer issue. It would seem to me that the fuel cutoff should be immediate when the key switch is closed or OSHA mandated seat switch is closed or both. In your case you don't have a seat switch (or you shouldn't ) so I don't understand the need for a timer. Do you have a two wire solenoid indicating a pull in coil and a run coil in the solenoid . In that case the pull in coil might be on to keep that coil from overheating with constant operation so I timer might be required to turn it off leaving the run coil to hold open the actuator rod. So then if the second wire is bad that migh explain why it shutdowns after a short while. Is the time increment from running to shutdown the same. If it is that might be the cause.

The other possibility is that something grounding out the wire(s) from key switch causing the solenoid to loose power. A loose connection at the key switch or somewhere between the key switch and the solenoid terminal can cause the problem.

Hope this helps.

 

[PoTreeBoy]

If you pull the wire connector off the solenoid while it's running does it keep running or does it stop?

 

[TitanTn]

It’s a 3 wire solenoid. Ground, 12 volt - stay open to run wire, and another wire that’s 12 volt just briefly as the engine starts. I think that’s what Jerry was describing much more intelligently.

i just tested it, and once running, it immediately shuts down when I disconnect the main 12 volt wire to the solenoid. But again, my problem is that after starting cold and running great for a minute or two (probably realistically 60 seconds), the solenoid shuts off even though there is still 12 volts to the main wire. Once the engine stops, a relay turns off the 12 volts about 1 second later.
The engine runs great, and it’s hard to put it under a load. It’s a 22kw generator and I don’t have have anything nearby to put a big load on it. But I’m confident that if I hold the solenoid open, it’ll run all day long. Something is turning the solenoid off even while it has 12 volts to it.
I don’t know rhe year model, but I’d guess early 2000s or late 90s.

 

[PoTreeBoy]

It’s a 3 wire solenoid. Ground, 12 volt - stay open to run wire, and another wire that’s 12 volt just briefly as the engine starts. I think that’s what Jerry was describing much more intelligently.

i just tested it, and once running, it immediately shuts down when I disconnect the main 12 volt wire to the solenoid. But again, my problem is that after starting cold and running great for a minute or two (probably realistically 60 seconds), the solenoid shuts off even though there is still 12 volts to the main wire. Once the engine stops, a relay turns off the 12 volts about 1 second later.
The engine runs great, and it’s hard to put it under a load. It’s a 22kw generator and I don’t have have anything nearby to put a big load on it. But I’m confident that if I hold the solenoid open, it’ll run all day long. Something is turning the solenoid off even while it has 12 volts to it.
I don’t know rhe year model, but I’d guess early 2000s or late 90s.

OK, you don't have the timer version.

You've just about proved the solenoid is the problem. I thought you said you had replaced it, but re-reading I don't see that.

Before replacing it, make sure you have a good ground and good connections at the connector. Even the briefest loss of power will let it drop out. But it sounds like it's getting hot and dropping out.

 

[TitanTn]

You did read it correctly. I replaced the solenoid. Both the original and the new one behave in the same way.

I’m pretty sure the voltage at the solenoid matches the output from the alternator. Is that too high? Almost 14 volts. Is there something that should be regulating that voltage so it’s a consistent 12?

 

[North Idaho Wolfman]

Make sure the hold and the pull are on the right feeds.
If the pull is powered to long it will overheat.
My solenoids on the V2203 have a filter on the input wires.
I'm not sure what the filter does exactly, but I suspect it's a diode and capacitor.
Try powering the solenoid from a stand alone power source and see how it reacts.

 

[PoTreeBoy]

You did read it correctly. I replaced the solenoid. Both the original and the new one behave in the same way.

I’m pretty sure the voltage at the solenoid matches the output from the alternator. Is that too high? Almost 14 volts. Is there something that should be regulating that voltage so it’s a consistent 12?

I doubt the voltage is the problem.

How new is this machine? Does it have mechanical fuel injection or common rail (there would be wires to the injectors)? Never mind, there wouldn't be a shutoff solenoid on common rail.

You wouldn't happen to have a wiring diagram, would you?

I'd hook jumpers from the battery to the solenoid and see if it keeps running. If it cuts off then, you must have gotten a bad solenoid.

I'm thinking on a generator, since they're made to run unattended, there may be a sensor/relay/timer or control card that's not present on tractors.

 

[TitanTn]

I'm guessing it's an early 2000's motor. I think it came out of a generator trailer. Most of the monitoring gauges are not with the generator. I had to add the fuel tank. But again, I've run this in the past for 20-30 minutes at a time with no issue. So it's worked before.

I'm pretty sure it's wired correctly at the solenoid because it's the same as the previous solenoid. But I'll switch the wires and see what happens.

I do not have a wiring diagram, but this thing is fairly simple. There's not too much added on from what I can tell.

I have powered the solenoid from a different source and it behaves the same way. Makes sense. It's not shutting down due to a loss of 12 volts. Something else it causing it to shut down. And what it sounds like you guys are saying is that there's nothing else that could shut it down. Yet the old and the new solenoid behave exactly the same way.

 

[GreensvilleJay]

does that engine have a 'low oil pressure' sensor ? If so, and it's 'bad', that would turn off the engine.
Not having a proper wiring diagram makes this hard to figure out...

 

[North Idaho Wolfman]

Look on the top back of the head, is there a sensor with 2 wires?
Look just above the starter is there a sensor with 2 wires?

 

[Henro]

I'm guessing it's an early 2000's motor. I think it came out of a generator trailer. Most of the monitoring gauges are not with the generator. I had to add the fuel tank. But again, I've run this in the past for 20-30 minutes at a time with no issue. So it's worked before.

I'm pretty sure it's wired correctly at the solenoid because it's the same as the previous solenoid. But I'll switch the wires and see what happens.

I do not have a wiring diagram, but this thing is fairly simple. There's not too much added on from what I can tell.

I have powered the solenoid from a different source and it behaves the same way. Makes sense. It's not shutting down due to a loss of 12 volts. Something else it causing it to shut down. And what it sounds like you guys are saying is that there's nothing else that could shut it down. Yet the old and the new solenoid behave exactly the same way.

Where are you connecting the voltmeter leads when you check the voltage?

You really need to check the voltage between the wires feeding the solenoid, and the engine block, if the block is part of the return path for current flow. Or at the wire leading back to the battery negative terminal if your setup uses a wire for the return path from the solenoid.

If the voltmeter negative lead is somewhere else, closer to the battery negative terminal, then you could have a problem somewhere between the fuel solenoid and whatever is used as the return path for current Up to the point where the voltmeter lead is connected.

In the event that your set up uses a wire to get back to the negative side of the battery, you could have a broken wire which intermittently opens and causes the solenoid to de-energize. You could still measure 12 V at the wires feeding the solenoid if this happens. Same with a circuit using the engine block as part of the return path.

Just saying that it’s possible to have 12 V on the one side of the solenoid, and still not have current flow through the solenoid windings, if the return path gets broken for whatever reason.

 

[Russell King]

I would try to remove the solenoid and test it separate from any thing else (use old one to test first?)

I believe that you have already proven that the engine runs with out the solenoid attached to the engine at all. What do you have to hold in what position to keep the engine running? Push or pull

What do you have to do to the solenoid to do same actions?

Is the engine wiring properly providing the signal to the solenoid?

 

[TitanTn]

Look on the top back of the head, is there a sensor with 2 wires?
Look just above the starter is there a sensor with 2 wires?

I'll have to check tonight.

Where are you connecting the voltmeter leads when you check the voltage?

You really need to check the voltage between the wires feeding the solenoid, and the engine block, if the block is part of the return path for current flow. Or at the wire leading back to the battery negative terminal if your setup uses a wire for the return path from the solenoid.

If the voltmeter negative lead is somewhere else, closer to the battery negative terminal, then you could have a problem somewhere between the fuel solenoid and whatever is used as the return path for current Up to the point where the voltmeter lead is connected.

In the event that your set up uses a wire to get back to the negative side of the battery, you could have a broken wire which intermittently opens and causes the solenoid to de-energize. You could still measure 12 V at the wires feeding the solenoid if this happens. Same with a circuit using the engine block as part of the return path.

Just saying that it’s possible to have 12 V on the one side of the solenoid, and still not have current flow through the solenoid windings, if the return path gets broken for whatever reason.

I didn't follow all of that, but I think I got the gist. I'm testing with the voltmeter on the bracket of the solenoid which is attached to the block, which is where the ground wire for the solenoid is attached.

I would try to remove the solenoid and test it separate from any thing else (use old one to test first?)

I believe that you have already proven that the engine runs with out the solenoid attached to the engine at all. What do you have to hold in what position to keep the engine running? Push or pull

What do you have to do to the solenoid to do same actions?

Is the engine wiring properly providing the signal to the solenoid?

I should bench test both solenoids, and I think I've done that, but it's been so long with so much testing I can't remember.

It's PULL to run, so if I hold it in that position it runs fine.

This is the tricky part. Both solenoids (old and new) cut off when they still have 12 volts to them.

So what I understand from you guys is that the black wire is ground, red wire is "hold" and white is "pull." So the white only gets 12 volts for a very short time at startup. Red seems to stay hot when the motor is running. I assuming this red wire is what keeps the solenoid open while running? I've attached a photo so you can see what we're talking about.