2016 LT40 Yanmar diesel no start issue

crosswind · February 28, 2018, 08:59:45 AM

So, I picked up the mill in Georgia took it home and unloaded it and stored it in the barn. When I picked it up it was obvious that the man the owned this thing did not operate it. He knew next to nothing about how to operate it.
This mill looks brand new with only having 140 hours on it.
Anyway I wanted to hear it run before I loaded it on the flatbed.So the hits the starter switch and the engine fires right up sounds fine, no smoke, or any negative sounds coming from the Yanmar diesel.
Well the engine runs fr about 30 seconds and shuts down, hit the key and it fires right back up, runs for another 30 secs, and shuts down. Well this went on for a few reps, but it ran long enough for me to know this isn't an engine issue so I loaded it and took off for home.

So taking a look at it last night It continues to do the same thing, runs for several secs and then shuts down. Almost sounds like it is running out of fuel.

Fuel shut off switch is open.

Anyone experience this ? Am I missing some other device on this mill that will shut the engine down?

I am going through my manual but haven't come across anything that leads me to think off any obvious problem.

ncsawyer · February 28, 2018, 09:35:48 AM

Do you have the new tier 4 engine, or the prior engine. My mill is a 2015 and does not have the tier 4 with all the emissions.

From your description, it does sound like a possible fuel issue. I would start with the fuel filter/water separator.

Keep us posted on what you find.

Kbeitz · February 28, 2018, 10:43:05 AM

Fuel cap vent? Might be making a vacuum in the tank.Try running it with the cap loose.

crosswind · February 28, 2018, 10:50:30 AM

I spoke with Jason awhile ago and he want me to check a 4 amp fuse by the radiator.
I work a day job so I won't be able to take a look until this afternoon.

NCsawyer, mine is, I believe the last model year before the tier 4. None of the regen stuff.

Thx for the info guys.

starmac · February 28, 2018, 12:38:39 PM

Doesn't sound like a fuel issue to me except for the fact it is purposely shutting the fuel off. I would bet it has a low water and oil switch, plus probably a sensor for heat and oil pressure, any of which could be shutting it down.

If it was a primary fuel issue, it would not easily restart. Generally if it is the low water or oil sensor, you can unplug the sensor and it should run, at least it does on trucks.

YellowHammer · February 28, 2018, 01:06:37 PM

It's hard to diagnose an engine problem without seeing it or hearing it, but always start with the easy stuff, especially since it's been sitting around before you got it.

Check or change the 3 F's first. Fluids, Filters and Fuses.

POSTON WIDEHEAD · February 28, 2018, 01:32:18 PM

When you crank it does it stay running long enough to rev itself up?
I turn the key on for 5 seconds, then crank and the engine will rev itself up while warming up.
Mine is the T4

crosswind · February 28, 2018, 03:17:55 PM

No, it doesn't run long enough to rev to the warm up speed.

I was wondering about a low fluid sensor. Still reading the manual to see if such a sensor exists on this mill

POSTON WIDEHEAD · February 28, 2018, 03:51:08 PM

Check and see if you have a fuel line or vent hose collapse right after cranking.

richhiway · February 28, 2018, 06:15:30 PM

I agree with the above,sounds like a safety low water,low oil pressure shut down. I would change the filters and all the fluids if it has been sitting more then a year. Check the fuel tank for gunk also. I have seen the pickup get plugged,then the gunk falls off and the engine restarts.

Resonator · February 28, 2018, 06:29:07 PM

Edit: I would check the fuel system first, (line, valve, filter, etc.), or bleed any air out of the fuel system that would cause a stall.

starmac · February 28, 2018, 07:29:30 PM

Well if it is a plugged fuel system and it will immediately restart after running the inj pump out of fuel, advertise at as a magical one of a kind diesel and you should get a fortune for it. If it is immediately restarting, it is not a plugged system, that is not to say that the filter isn't due for a change, but it is not what is killing it.

If there is a low water sensor, it will be on the radiator or water resevoir if it has one.

terrifictimbersllc · February 28, 2018, 07:54:28 PM

Crack the bleed bolt open on the fuel filter then squeeze the tank bulb till filter is full and all air out. Close it and repeat by opening the bleed screw or line where it goes into the engine. Lots of squeezing. To get out and rule out air.

brombones · February 28, 2018, 09:04:04 PM

My advice is time the shutdown. If it's a consistent 30 seconds or close to that, and it will re-start immediately every time, it's most likely an engine safety shutting it down.

30 seconds is pretty standard monitoring time for most engines safety shutdowns. Oil pressure/temp, coolant level/temp being the common ones. Common rail systems will have more.

Bufordht · February 28, 2018, 09:18:01 PM

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POSTON WIDEHEAD · February 28, 2018, 09:34:04 PM

The manual on my Tier 4 is at the mill right now but somewhere in the manual it said to be cautious about the fuel system. Its under high pressure and can cause injuries.
Not sure if your engine is like this to not.

crosswind · February 28, 2018, 10:26:50 PM

Quote from: starmac on February 28, 2018, 07:29:30 PM
Well if it is a plugged fuel system and it will immediately restart after running the inj pump out of fuel, advertise at as a magical one of a kind diesel and you should get a fortune for it. If it is immediately restarting, it is not a plugged system, that is not to say that the filter isn't due for a change, but it is not what is killing it.

If there is a low water sensor, it will be on the radiator or water resevoir if it has one.

Starmac, I kept thinking the same thing.if it was running out of fuel it wouldn't restart without bleeding the air out of the injection system.
I checked the 4 amp fuse that Jason from Woodmizer suggested. That was fine. I checked some of the other connections in that box of relays and such.
In then went back to the controls and cycled the clutch on and off a couple times, hit the starter switch, it ran for ten seconds then stopped. I hit the switch again and it fired right back up and continued to run like it's supposed to.
I ran it for 30.mins , shut it down, let it sit for a minute hit the key and again it ran until I shut it down.
So in the end I don't know what the heck it was, but for now it runs like a top.

.
I appreciate all the thoughts and ideas guys.
Someday I'm actually going to put a log on her and cut some lumber. But tonight I had to go back to training dogs, it's the busy time of my season.

Southside · February 28, 2018, 10:29:33 PM

I agree with Starmac - it's not starving for fuel, not given the fact it starts right up and runs that way. My bet is with a sensor, could be a low fluid level, including oil, could be the sensor has failed, or a wire to the sensor has gone bad. Do you see any sort of diagnostic port or coding system in the book that would give you a code?

Sawmill Man · March 01, 2018, 08:46:10 AM

Does the Yanmar have a fuel shut off solenoid? I have had them go bad and act like this on Kubotas.

highleadtimber16 · March 01, 2018, 09:20:26 AM

Sounds like something to do with the shut off solenoid, which I believe is on the back of the pump. Saying that, check your filters and lines first anyways. Do any of the warning lights on your control panel, come on before it shuts off?

armechanic · March 01, 2018, 10:22:44 AM

Does it have an electric fuel pump ? I have seen 2 1/2 ton Army trucks the fire departments have do the same thing and it was the primary fuel filter. They don't get enough fuel thru so they quit then with the pump running they will get enough fuel thru that they will start and run for a few seconds. Also could be the electric fuel pump bad and the fuel siphons slowly to the injector pump. Good luck, hope you find the problem.

Bluejay27 · March 01, 2018, 08:06:55 PM

We have a Yanmar diesel on our LT70, and after sitting unused for a month of cold weather, it wasn't making proper power. Would fire right up, idle fine, rev fine, but would drop toward 2500 rpm trying to hit normal sawing speeds in hardwood. Put some amsoil cold flow in and my brother sawed all day no issue.

We also have a whisperwatt 25kw diesel generator. Fire it up, count to 15, and if it doesn't die, then you're good to go. If it does, go wiggle the wiring harness for the water temp switch. Like others have said, this sounds like your problem. Does it lope or just die without any struggle?

Not the fanciest diagnostic method, but I would start by wiggling the water and oil sensor connections, maybe clean and grease them. I don't know any specifics on the sensors as far as ohming them out goes, but I would look there next. I got lucky with the generator since it has a water temp alarm light.