L3240 woes

[orangeandgreen]

My L3240 is having "spells" where the rpm's drop abruptly with no adjustment to the throttle lever. It has happened going across the field bushhogging, and going down a level paved road. Throttle is set to wot with 2700 rpm showing and it will just drop to 1000 rpm. I can clutch it and it may come up to 1200 or 1300 but no more. After a few seconds, it will recover to normal RPM and I am on my way again.
After the first couple times, I changed the fuel filter (part of the 300hr service) but it has done it several times since then. I have cleaned the air filter but that made no difference. The tractor doesn't smoke or seem to be running rough during the "spell" , it just slows down. I think it is probably a fuel issue but not sure. The diesel is fresh and I added Power Service to the last tank but the spells continue.
Sometimes they occur after the tractor has been in use a couple hours (bushhogging CRP) and sometimes they happen right out of the driveway, tractor isn't up to temperature.
Cars following me get pissed when I'm doing 6.5 mph.

Any ideas on where I need to look or what I need to try

Thanks

 

[The Fred]

It's a fuel delivery problem. Sounds like the lift (transfer) pump is going bad or else the supply of ffuel to that pump is being obstructed by something.
You could try to bleed all the air out of the system by opening the fuel bypass valve while running the engine but most likely I would run a pressure gauge off the output side of the transfer pump and see what's up.

Start by making sure the fuel filter is fresh. Make sure you have an uninterrupted supply of fuel to the transfer pump.

Good luck, Fred

 

[Baby Grand]

Siphon out the tank into a clean tub and have a close look what you have removed, and also look inside the now empty tank, for any foreign objects. I have read, on here, about a hunk of something that is floating near the bottom of the tank getting sucked into the fuel line port of the tank. This causes the engine to stumble and the resulting reduced speed of the fuel pump causes reduced suction in the fuel line, releasing the object, which allows the engine to operate normally until it gets sucked in, again, at some later time. Sounds like it fits your symptoms. Good luck, and let us know if you find the cause!

 

[coolreinfarm]

Is this tractor a HST, the engine speed is controlled by the ECU that computes a signal from the tachometer sensor, may be a control problem. The ECU should throw a code on the intellapanel. Just my 2 cents.

 

[orangeandgreen]

The tractor isn't a hst. I will flush the tank this weekend and see what I find. Thanks for the advice.

 

[orangeandgreen]

Tank was clean as well as fuel lines. It seems odd that it goes exactly to 1000 rpm each time it happens. Guess that my local dealer will get to investigate if it continues.

 

[Whitnel]

Hope you get your issue fixed with out too much of a hit to the pocket book. Please let us know what ends up being the issue. I have the same tractor but an HST so always looking to learn as much as I can about them.

 

[Rocky Hoffler]

Tank was clean as well as fuel lines. It seems odd that it goes exactly to 1000 rpm each time it happens. Guess that my local dealer will get to investigate if it continues.

Not familiar with model but is this a tier 4 engine? it sounds as thou the ECU is receiving a problem and putting it in reduced power. how long does this symptom last.

 

[orangeandgreen]

Not a tier 4. It lasts 5 to 10 seconds then begins to return to normal speed. Ran the tractor about 3 hours today without issue. Finished my bush hogging for the teat, hopefully.

 

[MHarryE]

It sounds to me like a governor problem as the symptoms you talk about don't appear to be really power related meaning they don't come on only when you are at 100% power although you are at full throttle. Do you run an additive in your fuel? The Grand L 40 series does not have a extremely robust filtration system - assume yours us like mine with only the one combination water separator filter.