L4240 Stalls when the ambient temp is hot.

[kleetus]

as the title says, My L4240 stalls when the ambient temp is over 70ish.
I just had a full service done, including fuel filter, oil, and hydraulics. It was happening prior to this as well.

It stalls when its idling, or under load (PTO or not). But only when its hot.

I ran it for 3 hours in the morning dragging a box scrapper and a harrow with no issues, when it was about 50. now this afternoon its 81 and it dies every 30 secs to 3 mins.

I loosened the fuel cap to see if there was a vacuum issue but had no effect.
It doesnt blow any kind of smoke at all, and it will start right back up every time, also with out smoke.
I dont think is a fuel quality issue, since it runs when its cold, the fuel is new, and 2 other farm vehicles use it, so I know its clean.
I have tried hard to recreate this in the cool but it wont.

its a 2011 or 12 if that makes a difference.

thoughts?

 

[Harry in Ky]

Not that I know the answer (because I don't) but when you say it "stalls." Can you describe what that means to you? The engine suddenly quits like you turned off the key? Or it slowly winds down and dies out more like it's running short of fuel? The first symptom would indicate it's probably electrical. The second would indicate it's something else.

 

[kleetus]

well I was mowing today with my PTO at 550 rpms and the tractor at about 2400 rpms, and it will lose all power, idle for a second then stall even with the gas to the floor

Other days I didnt have the PTO running but I run around 2000-2400 rpms usually.

when I start it up, it goes right back up to 2400 rpms

 

[alexpops]

Clean Air filter? clean screen before the intake? EGR valve? If it isn't fuel/could be air is too hot/not enough. Also, check the shut-off solenoid for heat/frayed wires. My ZT was jury rigged by a previous owner & if I accidentally hit the fuel switch, It'll bog under load but keeps sipping fuel until it dies or I kill the mower & just drive (or turn the switch back)

 

[Harry in Ky]

Well to me that sounds more mechanical than electrical. The tractor is old enough that it shouldn't have much other than a seat switch and the typical operator aggravation module that affect it electrically anyway.

When it does this, can you recall whether or not you hear the fuel shut off solenoid click consistently with the key going off and on? Can you see the fuel filter canister from the seat at all or is that all covered? Just throwing ideas around here, none of which I can think of that would be ambient temperature related.

This shouldn't matter either, but what transmission do you have?

 

[RjCorazza]

It's also possible that the electric lift pump is failing. When it's good and hot out, check for fuel flow after the lift pump.

 

[kleetus]

Well to me that sounds more mechanical than electrical. The tractor is old enough that it shouldn't have much other than a seat switch and the typical operator aggravation module that affect it electrically anyway.

When it does this, can you recall whether or not you hear the fuel shut off solenoid click consistently with the key going off and on? Can you see the fuel filter canister from the seat at all or is that all covered? Just throwing ideas around here, none of which I can think of that would be ambient temperature related.

This shouldn't matter either, but what transmission do you have?

I have the HST, but you bring up a point.. when it stalls it sounds exactly like it does when the seat switch is tripped. I might go run it in PTO mode with the seat up to see if it still stalls. do you know if there is a way to disable that?

 

[kleetus]

Clean Air filter? clean screen before the intake? EGR valve? If it isn't fuel/could be air is too hot/not enough. Also, check the shut-off solenoid for heat/frayed wires. My ZT was jury rigged by a previous owner & if I accidentally hit the fuel switch, It'll bog under load but keeps sipping fuel until it dies or I kill the mower & just drive (or turn the switch back)

Had a new air filter as well when I had it serviced. Going to go check for any loose wire.

 

[dstig1]

Debris in the fuel tank is a possibility. Warm temps perhaps loosen things up enough that it gets free and sucked into the inlet where it chokes fuel. Then it shuts off, fuel draw stops and floaters move back out of the inlet for a while until flow starts again. Wash rinse repeat. Or could be some wax-like goo in the diesel doing it.

I haven't had it happen but have read of several on here that have.

 

[Harry in Ky]

I have the HST, but you bring up a point.. when it stalls it sounds exactly like it does when the seat switch is tripped. I might go run it in PTO mode with the seat up to see if it still stalls. do you know if there is a way to disable that?

There's a way to disable most anything. Particularly so on tractors old enough they don't have computers with over riding control over everything. If your experimenting leads you to conclude the issue is indeed electrical (I'm not convinced of that yet) you can actually bypass all of that with some simple tricks. I've done it before on other tractors with similar systems. It's not hard, not permanent, (unless you want it to be) but once done and you operate the tractor for a few days and the "stall" problem doesn't re occur, you can work on narrowing it down and repairing the cause.

 

[kleetus]

went out last night and tested the seat switch, and it still stalls with the seat up, idling with the PTO running and not running.

got up early this morning and mowed 3 fields, no stalls at all (took 2.5-3 hours). Soon as it got over 75, it starts stalling.

the only way I can replicate it, is to run it when ambient temp is warm

 

[JWR]

This is wild... hard to figure. This is out in left field BUT has it ever been overheated before , especially for any period of time or very severely? I know of a Kubota 3 cyl that seemed to overheat a lot, people thought that was cured, and tht had gone on for months. When it was taken in for serious shop investigation we found that the engine had seized temporarily at times of extreme overheating. Users had been fooled by the temp gauge (which doesn't work after the coolant boils away.) To shorten the story th end result was not just a blown head gasket but a cracked head. And it was overheating much more when the outside air temp was 95.

 

[kleetus]

no it has never over heated. it stays at 4 bars once it warms up. I had considered the gauges but I dont really know how to test a gauge so thinking about it is as far as I got.

no lights come on, no errors, no smoke, no beeps.

 

[Harry in Ky]

Check your PM inbox.

 

[seville009]

Two things I would try/check:

The next time it starts to stall, completely remove the fuel cap (instead of just loosening it), and then just let it sit there for a bit without reducing the throttle and see if the engine goes back to normal.

Even though it’s been serviced, pull out the air filter and check it over. Also get into the complete air intake system (before and after the air filter) to make sure the entire duct work is free of obstruction.

 

[jonsstihl]

Have you actually pulled the radiator cap and visually verified there is coolant in there. With the engine cold of course.

I'm assuming the tractor starts and runs even when ambient temps are higher but that it stalls when engine temp gets hotter. do you have an infrared thermometer you could take a couple readings with...

I don't think that model has a lift pump. it is gravity feed to the fuel filter housing. no turbo and no EGR. I am leaning towards electrical. maybe something is causing that fuel shut off solenoid to activate.

 

[jonsstihl]

I would clean out the radiators really well with air then water to make sure it is not actually overheating. maybe there is a protection when the temp gets too hot independent of the gauge.

 

[kleetus]

Have you actually pulled the radiator cap and visually verified there is coolant in there. With the engine cold of course.

I'm assuming the tractor starts and runs even when ambient temps are higher but that it stalls when engine temp gets hotter. do you have an infrared thermometer you could take a couple readings with...

I don't think that model has a lift pump. it is gravity feed to the fuel filter housing. no turbo and no EGR. I am leaning towards electrical. maybe something is causing that fuel shut off solenoid to activate.

I have personally removed the radiator cap and verified its nice and green and full.

its not when the engine gets hot, I mowed for 3 hours this morning when it was cool. once its warm I can go out and it will stall right away. But yeah I can check it with an infrared. When I say hot I mean 80 btw.

I also checked the battery and its putting out 12.75v

Tomorrow I will check the air lines and see if there is anything in there. I have checked the filter already.

The tech was here today and has never heard of this happening, he's going to run it by the Kubota rep..

Maybe this is "the force" telling me its to hot out, and I should be resting..

 

[JWR]

Let's hope there is no such thing in tractors BUT, the major auto/truck manufacturers all have systems that sense potential major damage to the engine or the transmission and put the vehicle into "Limp Mode." Most of the time turning off the ignition and restarting clears the issue at least temporarily.

I would do a pretty quick search of your manuals (and ask the brightest tractor mechanic at your dealer) if Limp Mode exists for your specific tractor model.

 

[kleetus]

well after a few weeks of cool weather, it finally got warm. Tractor was running good while it was nice.

On the first hot day it started stalling pretty bad, when I got back to my shop there was hydraulic fluid coming out of the silver thing (or above it and dripping down) in the pic. Service folks said it most likely some seal on the transmission in there that doesnt go bad often.. of course. I dont remember exactly what he said it was, but required essentially split in half.

Havent heard back yet on the exact issue. But I am guessing the stalling was when the fluid got to a certain temp it would start to leak then stall out.