Surging, even with new MCOR

[scoottheboot]

I have a 2014 Precedent that I bought last year. It ran great all last season. I put it in a shed for the winter (following the book) and plugged the ERIC charger in all winter long. When I got the cart out this spring, I could not get it to move. Even with Tow/Run on and the key on, putting the F/R switch in R did not cause a beep. After rocking the F/R switch back and forth a few times, the beep started working and the cart moved in Reverse. That said, it took a few more attempts with the switch back and forth I finally got the cart moving forward.

That said, the cart will only run at half speed (7 MPH vs 12 MPH) (I'm using GPS to capture speeds). After running for a few minutes, the battery indicator came on. I threw ERIC on the cart overnight. The next morning, I unplugged the charger and let it sit all day, when I came home, out came the voltmeter and I found 1 bad battery. These are the original (5 yr old batteries), so I purchased a new set and installed them.

After install, I got the cart back out and started driving. The speed was still at 7 MPH, but on a flat or downhill it was surging up to 10 - 11 MPH (it would not hold that consistently, it was lots of surging). Going uphill, it slows down to 5-6 MPH.

Some googling found this could be an MCOR, so I tried, the 'neutral, hit the pedal 30 times trick'. No effect. I bought a new MCOR and installed it today. No effect, it's behaving exactly the same.

Here's the other things I've done with no effect:
- Checked speed sensor. Clean as a whistle
- Checked all electrical contacts to the motor - clean and clear and tight
- Opened the computer / solenoid compartment and inspected
- All connections clean and tight
- No frayed wires
- Fuses all good and tight
- Pulled F/R switch, checked contacts, all tight, re-seated

Things I need to check:
- Pull wires from the F/R switch and jump the F circuit to see if it works better


It almost seems like the computer reset the speed code that was set, or, the computer is bad. I should note that about half of the time I put the cart in reverse, the alarm does not come on until I toggle back and forth a few times (why I want to bypass the F/R switch).

It could also be the solenoid, any way to test this out?

My 6 year old pointed out (before the battery replacement), the motor was making a noise, I'm assuming it was due to low voltage, it's not making it now, but I wonder if I fried the motor itself. Any thoughts on testing?


Thanks in advance all!

[scoottheboot]

Okay, So I just tested bypassing the F/R switch and the behavior is the same. Looks like a faulty computer / motor?

[Fairtax4me]

More likely the speed sensor has failed. That's very common and will limit the cart to about 8mph. Try the roll away test. On flat ground, key ON, brakes off, push the cart by hand and you should feel resistance and the reverse buzzer should beep. If it rolls freely the speed sensor has failed or the magnet is damaged.

Order a new sensor and magnet from one of our site sponsors, or direct from a club car dealer. The cheap sensors online are not reliable.

[NoleFan4Ever]

Yes, that does sounds like you are in "Limp" mode. Do the test FT4M mentioned to prove it. If that is not it, we can do some more testing.

[scoottheboot]

Failed the test. I ordered a new speed sensor and (high speed) magnet. Will report back next week.