Jerky acceleration after accident - 2004 EZGO TXT

[anpark]

I have a 2004 EZGO TXT which has been converted to 48V - Alltrax 500A controller and Admiral B4 motor.

I was washing it the other day with the key on, switch in forward, and parking brake on. All of a sudden the cart took off at full speed (at least, as fast as it would go with the parking brake on) and ran into a block wall about 15 feet away. Yikes! Something related to the accelerator must have shorted out with water to cause this. It stopped when the front left tire hit the wall, and I shut off the key immediately and let it dry for a bit. After it dried, I took it for a drive and noticed two problems: the front axle weldment is bent and the cart is very jerky when accelerating slowly.

I'm replacing the front axle weldment today, but I'm not sure where to start looking into the jerkiness. When pressing the throttle lightly, the solenoid clicks, and then the golf cart jerks forward repeatedly. If I press the accelerator harder, it accelerates smoothly and drives with no issues. However, any time I creep along or go slow this jerkiness happens. This happens in both forward and reverse. I'm wondering if something in the motor or differential got damaged when the cart suddenly stopped against the wall. I'd guess it hit the wall at about 5mph.

Any suggestions on how to troubleshoot this jerkiness?

And yes, I've learned my lesson to at least turn off the cart and put it in neutral when washing it. At least there was no damage to the block wall.

[Volt_Ampere]

You can connect your laptop to the Alltrax and run the monitor program to determine what is happening with your throttle. I suspect your throttle is still wet and acting up at low throttle. You need the Alltrax software on your laptop to do this. Very handy tool!

[JohnnieB]

Originally Posted by anpark

And yes, I've learned my lesson to at least turn off the cart and put it in neutral when washing it. At least there was no damage to the block wall.

Since you mentioned a B4 motor, I suspect you have an XCT48500-PDS controller.

You want to put the Run/Tow switch into the Tow position before washing cart.

[anpark]

Yes, I have the XCT48500-PDS controller. Flipping the tow mode switch the next time I wash it is a good idea - thanks.

Ok, I connected my laptop and the throttle seems to be working correctly. Pretty smooth operation from 0 to 100% on the throttle. I also pulled the floormat and inspected the ITS. It's totally dry in there. I didn't expect anything to still be wet, since it was a week ago when I washed it and it's been baking in the AZ sun since then. So, I don't think the problem is the throttle or ITS.

While the cart is up on the jackstands, I can tell there is a significant amount of play in the rear end. I think this is what is causing the jerkiness. It's not very jerky off the ground, but I think the play in the rear-end (or the motor) is causing the jerkiness on the ground. Any idea how to troubleshoot this?

[anpark]

I just took it for a test drive and the jerkiness is gone. I can't explain it. Perhaps the problem was with the ITS and when I had the cover off for a couple hours and inspected everything somehow that cleared it up? I did clear the throttle auto cal in the Alltrax toolkit while I as troubleshooting too, so maybe that fixed something? I'm going to drive it for a few days and see if the problem reoccurs.

As I said, there is play in the rear end when it's off the ground, but I don't know if that is normal or what the tolerances are. Maybe it's always been that way.

[Volt_Ampere]

Sounds like it's fixed now that it really dried out. I have seen several cases of carts failing to work after washing and they usually do work after drying out. I'm very careful when I wash my carts not to get the electronics wet but it's always possible to get things wet down by the accelerator pedal.

[JohnnieB]

Originally Posted by anpark

I just took it for a test drive and the jerkiness is gone. I can't explain it. Perhaps the problem was with the ITS and when I had the cover off for a couple hours and inspected everything somehow that cleared it up? I did clear the throttle auto cal in the Alltrax toolkit while I as troubleshooting too, so maybe that fixed something? I'm going to drive it for a few days and see if the problem reoccurs.

As I said, there is play in the rear end when it's off the ground, but I don't know if that is normal or what the tolerances are. Maybe it's always been that way.

It is an open differential without and backlash adjustments, so the more the gears wear, the sloppier it gets.

[radioman]

Originally Posted by anpark

I just took it for a test drive and the jerkiness is gone. I can't explain it. Perhaps the problem was with the ITS and when I had the cover off for a couple hours and inspected everything somehow that cleared it up? I did clear the throttle auto cal in the Alltrax toolkit while I as troubleshooting too, so maybe that fixed something? I'm going to drive it for a few days and see if the problem reoccurs.

As I said, there is play in the rear end when it's off the ground, but I don't know if that is normal or what the tolerances are. Maybe it's always been that way.

Check the cable from the pedal box to the controller. Look for a small inline connector or a splice that may be corroded. A little corrosion and water will create a false ITS signal.