Ezgo txt lithium build with random throttle issues

[Conradconrad]

Hello, I have a ezgo txt with a custom D&D motor made by emp, alltrax 500 and a lithium big battery 48v 105ah battery.

Cart ran like beast no issues for over 1.5 years. I had a 7k rom limiter set so it could get to 29mph in no time(with 18inch tires). Then it sat for about 3 months with minimal use(maybe three 1 mile drives in 3months). It seems to have developed a strange throttle problem.

Very very feather pedal touch(1mph or less) the cart will feel very jerky moving forward. Upon normal driving on city streets it feels like the cart won't go past 15-18mph. Normal top speed is 29 mph(limited at 7k rpm's). Usually after about 15-29 minutes of driving it seems to "work itself out" and pick up speed. However even after "working its self out" it will get to about 25mph and slowly continue to increase speed very very slowly.

I ran around a few times with the alltrax monitor up and it shows correct throttle positioning from 0-100% at corresponding times. It shows the speed sensors rpms as well.

I checked the speed sensor and the magnet looks fine.

I did uncheck the "enable speed limit" and the problem became significantly worse if that help.

I don't think it's a micro switch problem, could it be an its issue or a speed sensor issue? I attempted a roll away test but am really not sure if I performed it correctly. Key switch on, forward switched, rolled the cart down the driveway about 15-20ft as fast as I could get it going and nothing.

[augiedoggy]

If it were mine id check the brushes in the motor and double check wire connection points for a poor connection.

[DaveTM]

I’m thinking (as AugieD said) it’s a cable connection. Pull your cable connections & clean up & tighten each one. Including the motor attachments.

[Conradconrad]

Checked all the connections. Issue still persists. In fact as I began driving the cart after about 450 ft I stoped at a stop sign and had zero forward movement regardless of pressing the pedal. I pressed several times and turned cart in and off quickly with no response. Got out an pushed it maybe 10ft to the side of the road and when I tried again it worked. Could it be a bad speed sensor? As I previously mentioned when I disable "enable speed limit" in the alltrax it seems to make the problem much much worse, I would describe it as hesitant sluggish accerlation with subtle surges of normal power.

[DaveTM]

These can be perplexing. If the cart is currently sitting in your garage and doing the same, there are "sticky" post on the forum that will help you DX the problem.

What I do when "I don't get it" is to take my Multimeter and start checking voltages at "given places". I start with the obvious like the POS and NEG at the pack, and then trace voltages to connections where I should get readings. If I don't get expected readings then I've narrowed it down. I've done this before and I put the rear axle on jack stands to let the wheels spin. I you do that, don't go "full throttle" and let the wheels spin at top speed. That's a sure-fire way to have your motor fly apart.

If you do set the cart on jack stands, make darn sure it's a solid placement.

One other thought is ....how old is your controller? If it's ten plus years or so, that may be the device that's going south.