Speed surging mid pedal

Pablo8

Hello,
I recently bought a 2005 CC Precedent. Initially it ran very well. Lately it runs poorly. The problem is that when I press down on the acceleration pedal, it runs smoothly then as I speed up, about 1/2 down on the pedal, the car surges and does this unless I press the pedal all the way down. With the pedal all the way down, it runs smoothly again, but I don't think I am going full speed.
I found a detailed diagnostic manual for this model online. I have tested the speed sensor, the MCOR, and the solenoid. They all check out ok. I put my meter across the field windings of the motor while driving and can see the voltage start out smoothly and rise to about 9 volts with thr pedal about 1/2 way down. Then it drops to OL over and over in about .5 second cycles until I get the pedal pushed nearly all the way down. It then stays steady around 15 volts. The armature windings ramp up much higher and I can see a voltage drop during those cycles. It peaks out smoothly at 49V with the pedal fully depressed.
I'm usually pretty good at troubleshooting but this one has me stumped. Anyone ever had this problem?
I'm wondering if I have a problem with the motor or the Curtis controller.
Thanks for the help in advance.

BGW

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mrgolf

Sounds like mcor. Turn key off press go pedal about 20-30 times to the floor if that helps the mcor wipper switch has oxidized. Get new one from David @ revolution carts. Site sponsor.

Pablo8

The unit on my cart is a MCOR 2. I see there is an upgrade to MCOR 4. Is this the best solution?

mrgolf

If the test above shows bad mcor then yes. Don't buy the cheap ones online. They are no good. Get one from David and be done with it.

Pablo8

Update:
I did the pedal thing two times 30-40 times each. There may be a small improvement but not anywhere near normal. I checked with the meter again and because I was going by memory, my first measurements were a bit off. The field motor voltage is smooth up to about 4.5V then from there to about 9V, there are those .5 second surges. I realized that my meter was set for auto ranging and that was why I was getting the OL'S. Actually the surges peak at around 10V. When the pedal is fully pressed, it smooths out again and holds steady at around 10.5V. Also of note, when in reverse, the voltage is smooth from -0 to -25V and the cart goes much slower which I believe is normal.
Should I assume the problem must be the MCOR?

TahoeDawgZ71

Sounds like an MCOR to me. Check your pedal assembly and make sure you order the correct MCOR. If you've got the Gen1 pedal assembly in your Precedent you'll need to order an MCOR2. If you've got the Gen2 pedal, the MCOR4 conversion kit AM293001 is what you'll need.

Here's some good reading for you...
http://www.revolutiongolfcars.com/#!...cor-guide/cwqo

Pablo8

I ordered the MCOR 2 from your online store (revolutiongolfcars). Approximately how long will it take to ship to north central Ohio?
Thanks.

TahoeDawgZ71

I had a shipment come in today but they didn't come in until after the postal pickup. It will ship tomorrow. You should see it Tuesday. Wednesday at the latest. Thank you for your order.

Pablo8

Ok. Thank you.