EZ go TXT no go....

[a65l]

Ok. Swapped wires on FNR switch. Cart runs forward only. No bueno.. still cuts out. Will cruise around for quite a while on partial throttle, but if you floor it, it will eventually cut out. And it almost always happens after you take your foot off the gas and coast...

To refresh, I hear the solenoid clicking. The onboard battery voltage is showing 39.something. No drop in voltage when I push pedal. The cart will "lunge" or lurch forward just a hair sometimes when you push the pedal, but not always. I felt around the switch, esc, motor and wires and feel no hot spots, at least none that are apparent to me. All the wires look decent.

So.

I need a new FNR switch anyway, the old one I noted while cleaning it up was extensively cracked around the shaft, and it has a lot of play when you move it. Wires? I cleaned the ends on all of them during reassembly, and none of them looked like they were damaged, or had loose eyelets. The cart dosen't seem to be dragging excessively, in fact, it's very easy to push!

On an other other aside, it rides a lot better without shocks....

[mgray70]

Sounds to me like a solenoid contact issue, or a bad connection in the ITS throttle wires. Check the 4 pin Molex connector that is located somewhere between the controller and the throttle. Some of the older TXT like the medalist are under the cart, and others near controller. Check it for corrosion.

Sent from my SM-G970U using Tapatalk

[a65l]

Any downsides to bypassing the solenoid for diagnostic tests?

[scottyb]

Originally Posted by a65l

Any downsides to bypassing the solenoid for diagnostic tests?

One downside is you eliminate the safety shut off switch (aka the solenoid) so it is only for testing.
Another downside is the test results are often misinterpreted

[a65l]

Ah, sometimes life gets in the way.

I replaced the F-R switch, as the old one was cracking around the center boss and had some play in the shaft. Hasn't changed a thing. I still haven't gotten around to bypassing the solenoid, mowing season is starting and I'm also trying to finish up some drainage projects before it dries up for the summer. Other than occasionally dying, the cart seems fine, no funny noises coming from motor or diff. I did replace the steering shaft as the old one was very loose on the rack and pinion splines.

I also installed a Vectron energy monitor. It shows, that under full throttle, the batteries are putting out about 130 amps, which dosen't seem excessive to me. I'm running out of components to suspect here...

[orangeman6]

Is thermal cutback not a possible cause? Is the controller getting warm when this happens?

[handtools]

Originally Posted by mgray70

Sounds to me like a solenoid contact issue, or a bad connection in the ITS throttle wires. Check the 4 pin Molex connector that is located somewhere between the controller and the throttle. Some of the older TXT like the medalist are under the cart, and others near controller. Check it for corrosion.

Sent from my SM-G970U using Tapatalk

Have you checked this connector yet? Most eliminate it by cutting it out and soldering/shrink wrapping or butt connectors/shrink wrapping the individual wires.

[a65l]

Sorry for the gap here.. down for some stuff. Got a replacement EZ-Go brand solenoid and swapped it out. Next time I'll actually disconnect the batteries.. apparently ground to the hot side of the solenoid will melt the wire on the resistor, so I'm running around sans resistor until I can source another one. Anyhoo.... have run it a bit here and there and...

No cutting out! And as a side note, the new solenoid engages with a noticeably more pronounced click than the old one. I'm not gonna sign this one off for a few days, but it would have quit by now on the old one.

My only explanation is that the kid I bought the cart from knew nothing about golf carts. He stated that he had purchased a new solenoid, b/c he read that they were problem areas and the old one might have been bad. There are no markings on the old unit, just a stamping that said "36V". So hopefully we got it here...

[a65l]

Apparently my troubles are not over. Noted that the cart seemed to be slowing down the other day, but battery voltage was constant. Didn't note what the amp draw was doing, however. Then, the cart started not starting again.... but would go if it was nudged forward or reverse, and bumping to full throttle.

I had made this check before, but pulled the motor wires to check resistance across the motor again. Lo and behold, I get 0.2 ohms across the field coil, but in the megahoms range across the commutator/brushes. Resistance which changes as I rotate the motor... and actually gets as low as 300 or so ohms in one location. That's not right..... So, out comes the motor, easy enough to remove the coils, and I see that the commutator is black all the way around. No smell of burnt electronics, however. And I did note that there's oily residue all around, more greasy oily than wet. Anyway... some time later, after multiple cans of contact cleaner and some scotchbrite/crocus cloth I wind up with this:



Which looks much better than it did before. Now I get 0.5 or so ohms across the commutator, it still moves but never gets above 1 ohm. Question is... what should the resistance be? Am I in the ballpark here? Next step is going to be finding a motor shop in the area that can do a full service to the motor, clean and cut the commutator, etc etc... and probablly wouldn't be a bad idea to replace the bearing as long as it's out, and new brushes since they're not terribly expensive.

[a65l]

So, hopefully my saga is at an end here. Couldn't find anyone locally to rebuild motor, so just ordered new one from D&D motor systems. Bolted right up, cart is smooth and fast now. Plus draws less amps at speed. Win win, I think..