L4740 Auto Throttle Advance

Tyler_LaRue

New member

Equipment
B1700HSD, L4740 HSTC
Sep 25, 2020
28
3
3
Ohio
With winter upon us I was on the road today plowing some driveways. I tried to use the ATA for the first time. With the lever engaged and also auto throttle selected on the dash I pressed down on the peddle and the tractor moved and the rpms began to rise as it should then within a second or two the RPMS bottomed out even though the peddle was still pushed to the floor. Each time I’ve tried this as been the outcome no matter where I place the throttle lever to start. Has anyone else experienced this ? It appears the electronics are initially communicating but then it stops working almost immediately. Any advice ?
 

SDT

Well-known member

Equipment
multiple and various
Apr 15, 2018
3,244
1,033
113
SE, IN
With winter upon us I was on the road today plowing some driveways. I tried to use the ATA for the first time. With the lever engaged and also auto throttle selected on the dash I pressed down on the peddle and the tractor moved and the rpms began to rise as it should then within a second or two the RPMS bottomed out even though the peddle was still pushed to the floor. Each time I’ve tried this as been the outcome no matter where I place the throttle lever to start. Has anyone else experienced this ? It appears the electronics are initially communicating but then it stops working almost immediately. Any advice ?
Normal if stall guard is on and/or tractor is overloaded.

Pushing the HST pedal to the floor calls for maximum speed, thus requiring the most power. Even if the ATA calls for increased throttle, the engine will not be able to increase RPM if overloaded.

The hydro pedal is not an accelerator pedal although the distinction is blurred a bit when ATA is on.

It is possible to make a HST+ tractor buck like a bronco if HST+ is in auto and the load is great enough that the engine cannot produce demand speed in High but can in Low. Such conditions cause the HST+ to continuously shift from High to Low and back to High creating a bucking effect.

SDT
 
Last edited:

Tyler_LaRue

New member

Equipment
B1700HSD, L4740 HSTC
Sep 25, 2020
28
3
3
Ohio
Normal if stall guard is on and/or tractor is overloaded.

Pushing the HST pedal to the floor calls for maximum speed, thus requiring the most power. Even if the ATA calls for increased throttle, the engine will not be able to increase RPM if overloaded.

The hydro pedal is not an accelerator pedal although the distinction is blurred a bit when ATA is on.

It is possible to make a HST+ tractor buck like a bronco if HST+ if in auto and the load is great enough that the engine cannot produce demand speed in High but cannot in Low. Such conditions cause the HST+ to continuously shift fromn High to Low and back to High creating a bucking effect.

SDT
I wasn’t pushing snow at the time I was just driving down the road. In my driveway from a stop with ATA on if I press the peddle down it takes of revs for a moment and then the RPMS bottom out again
 

SDT

Well-known member

Equipment
multiple and various
Apr 15, 2018
3,244
1,033
113
SE, IN
I wasn’t pushing snow at the time I was just driving down the road. In my driveway from a stop with ATA on if I press the peddle down it takes of revs for a moment and then the RPMS bottom out again
Uphill?

Does it do so if the hydro pedal is gradually pushed calling for more modest acceleration?
 

kubotafreak

Well-known member

Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Sep 20, 2018
1,045
390
83
Arkansas, US
Take stall guard off and try again to prove SDT's point. If it still stalls the system probably has other issues. If it does not stall then I would preform a factory reset on the throttle components. I have the directions or a gl60, but im sure someone on here has a fsm for gl40.
 

Tyler_LaRue

New member

Equipment
B1700HSD, L4740 HSTC
Sep 25, 2020
28
3
3
Ohio
Uphill?

Does it do so if the hydro pedal is gradually pushed calling for more modest acceleration?
No. It doesn’t seem to work at all. Is there an adjustment or a fuse or connection I should be looking at ? The dash light comes on but no RPM change when I press the pedal
 

Tyler_LaRue

New member

Equipment
B1700HSD, L4740 HSTC
Sep 25, 2020
28
3
3
Ohio
I was able to solve the problem. When you move the ATA lever from off to on a small roller pushed a pin that physically locks the peddle and throttle together. The roller was not pushing the pin far enough and it would just barley catch causing the ATA to work intermittently.
 
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