Grand L5030 starts/idles perfectly but chokes when loaded.

[crazyal]

I wouldn't rule out a transmission problem. Do you have any PTO driven attachments that can put a load on the engine without it moving? The fact that all three gears are acting the same sounds less like an engine problem. In low you just aren't putting any load on the engine if you are just driving around.

 

[slowzuki]

If the transmission is hauling it down, the engine should be making smoke like when the have the loader relief going while trying to scoop into a pile with the hst floored.

I wouldn't rule out a transmission problem. Do you have any PTO driven attachments that can put a load on the engine without it moving? The fact that all three gears are acting the same sounds less like an engine problem. In low you just aren't putting any load on the engine if you are just driving around.

 

[crazyal]

If the transmission is hauling it down, the engine should be making smoke like when the have the loader relief going while trying to scoop into a pile with the hst floored.

My 4240 doesn't make a lot of smoke when loaded down.

 

[texasjohn]

WHEE....I FIXED IT!!!

Thanks for all your good ideas!

The shop manual just paid for itself!!

I'd read thru it yesterday but didn't find anything that helped.

I talked this morning to the dealer's mechanic.... his first impression was that some cutout switch was kicking in, but he couldn't suggest anything except the seat switch. I disconnected the switch and with a VOM proved to myself that the switch was operating. So, went back to the shop manual.

This time, I saw that there is something called a tachometer sensor (electronic)....hmm....hunted it down, just under the stop engine solenoid and in same area as all the fuel injection stuff, hidden under a rubber protective shield. I unplugged it, dusted it off/blew into both sides of the connector and reconnected it. My impression was that the connector had been properly seated and not too dusty. Nevertheless, I gave it a try...not really expecting to have resolved the problem.

YEP, somehow that connector must have been the problem... all is well now and I'm off to continue disking.... ah, yes, at least 10 hours of seat time in front of me

Thanks again.... am soooooo glad am not having to replace fuel pump or anything with the word injector in it!!

 

[slowzuki]

Hmm, that sensor is normally just used to confirm the engine is running, nothing fancy, the neutral postion switch on the foot rocker must have been what was shutting the engine off when there is no tach signal. The 5030 doesn't use a computer to run the engine, only some safety switch logic in the intellipanel.

 

[slowzuki]

Probably not, its basically a similar motor with the pump turned down. The 5030 is the most hp in that engine displacment and no turbo. She makes a light haze when under full load. Often don't see it during the day but it lights right up at night with the cab work lights on.

My 4240 doesn't make a lot of smoke when loaded down.

 

[David_Kb7uns]

On the Grand L xx30 series the only interaction between all the electronics and the engine is through the Fuel Shutoff Solenoid.

David Kb7uns

 

[crazyal]

It sounds like Kubota has it set up with a limp mode. On some cars if some sensors die the car will be engine or speed limited so you're not dead on the side of the road. I wonder if the GL40s will give an error code?

 

[slowzuki]

No there is no limp mode, the only thing the dash computer can do to the engine is shut off the fuel solenoid or prevent the key start from working. If you cut all the wires, and run 12v to the fuel shut off, you can run the engine. All the other stuff is fluff except on a GST transmission where it runs the shifting.

It sounds like Kubota has it set up with a limp mode. On some cars if some sensors die the car will be engine or speed limited so you're not dead on the side of the road. I wonder if the GL40s will give an error code?

 

[David_Kb7uns]

If you cut all the wires, and run 12v to the fuel shut off, you can run the engine.

Have a D782 in the mower and a D902 in the BX and they do not even have run coils on the solenoid, just the kill coil, so once started they do not even need 12v to run.

David Kb7uns