EZGO RXV 08' Extreme Jerking when pressing the gas pedal

[Mattchandler]

I've talked to dealerships they all want me to bring it in, I'd rather fix it myself if I can. When you press the "GO" pedal down or roll the cart in tow mode it jerks and shakes the cart in forward or reverse. I thought it was the brake setting and then releasing. I cleaned all connections and tightened up all battery cables. I took the motor brake off and the problem is still there. That lead me to think that it could be in the gear set, because it can also happen while in Tow mode. After talking with service people from EZGO and different dealers around. They seem to think that it could be in the speed controller. I just read up on the speed sensor, so that could be my problem also. If anyone has experienced this problem please help, or any other ideas are welcome also.

[HiTechRedNeck]

Speed sensor is "out of the loop" in tow mode.

1) To rule out brake remove brake and put cart in tow mode.
is problem gone?

2) to rule out controller issue - Put cart in tow, key to OFF, disconnect battery cable to controller (B+)
is problem still there?

If problem is there with brake off motor and B+ cable dis connected,
problem is mechanical in nature. --hub area(bearings?), differential or motor.

Use care when working around batteries & bat cables.
Be sure to put cart in tow AND turn key OFF before messing with battery cables.


Hope this helps !!!
Keep us posted !!!
Pics if it is weird or interesting !!!!!!

[Mattchandler]

I read up a little on the controller solenoid. To check it I measured each battery individually, all had 13V. Turned the cart on and put it in the forward position. Checked the battery side of the solenoid it was 13V also. Measured the controller side of the solenoid it was 13V. What I read online was the solenoid was bad.

[Mattchandler]

Well solenoid was not the problem. Took the motor off and the rotor has alot of play on the side that hooks up to the gear the bearing on the brake end has no play.

[cgtech]

I do not think the speed sensor is "out of the loop" while in tow mode, as the Curtis controller has a "max towing speed" parameter (think its set to 12.5mph default). The "speed sensor" AKA encoder seems like a likely culprit to me.

[custom carts]

i agree with cjtech

[Mattchandler]

Does anyone know how to check out the speed sensor? I'd hate to tear apart this motor if I don't have to.

[cgtech]

You would need an oscilloscope to do it correctly. The handheld scanner might allow you to catch it, but might not. Encoder failures do not always throw a code, and the "motor rpm" monitor field does not always refresh fast enough to catch such a short glitch. It makes something like 32 each high and low pulses per motor revolution (pretty tough to catch without some faster test equipment than a standard volt meter). Really, lifting the motor out of the cart and carrying it to the bench is the hardest part, changing the encoder out of the motor is easy. Look at your motor with the rear access cover removed from the cart body (black plastic panel in golf bag area), if your motor has a sensor attached with one torx screw, right next to the axle flange, you are in luck and motor removal is not required (there are 2 slightly different motors, the major techincal difference is the tach sensor location). Check out the troubleshooting guide on here for your controller type thats available on this forum, it has tons of good info.

[Mattchandler]

Ok Thanks CGTech.

[Mattchandler]

Well, I megged and ohmed the motor and it's all good. I cleaned everything and took my time checking all the connections while I assembled the cart. There's a 4 pin connection at the motor. When I plugged them together the problem was present. I can unplug that, put the cart in tow and the gear selector in N, push it all over the garage, nothing happens. I'm guessing the controller is fried and will need to be replaced.