MCOR-4 Disassembly

[scottyb]

My 2014 is starting to surge at low/med speed. It has not been wet since I got it. I suspect the MCOR because, well, it has one

[Tom47]

Originally Posted by Sergio

The resistance track is a much more robust version of a regular potentiometer design as used on Curtis "PB" box series and some other cart manufactures.

Aside from driving through deep water or blasting the MCOR with a pressure washer, it seems hard for contaminants to get inside.

The switch actuation design is where I see potential for trouble, It appears there is a hard-stop that prevents the lever from pressing too hard against the switch plunger if the cart pedal assembly is not in good working order/adjustment.

What I cannot tell by the picture is if there is any spring or other energy absorbing design on the white plastic part that presses the switch plunger.

I would think that when someone releases the pedal abruptly, the MCOR arm would hit the switch plunger with great velocity and potentially damage the internal snap mechanism.

Anyway, that part is custom to Club Car but you can probably just get the stock series 16 switch below and cut the 2 outside tabs (N.O.) as they are not used anyway.

https://www.mouser.com/ProductDetail...tches/16-4044/

Thanks for taking the time to take one apart and post the pictures.

Sergio, there is a spring loaded plunger on the switch actuation. The pictures do not show this clearly.

I don't think rapid switch actuation would be an issue with it. However, I really don't know why mine showed 30 to 50 ohms instead of 0 when it was installed in the cart.

I could hook up the ohm meter to the contacts for the switch, push the pedal, and it would go to 0 ohms but if I tapped lightly on the MCOR it would regularly show 30 to 50 ohms. Since I took it apart and reassembled it, it works fine even when I tap on it.

When I get done with my Alltrax upgrade to IQ, I will take it apart again and get some more photos of the innards.

BTW, the switches shown by Mouser should work fine.

[Tom47]

Originally Posted by scottyb

My 2014 is starting to surge at low/med speed. It has not been wet since I got it. I suspect the MCOR because, well, it has one

It is easy to check the resistance right at the MCOR plug pins while pushing the pedal slowly.

Fortunately, in spite of all the MCORs in carts of forum members, the failure rate seems pretty low with the Mexico OEM ones. Maybe the Chinese knockoffs also.

[Sergio]

I kept thinking about the entire throttle linkage and how it that can torque the MCOR off track, so I decided to run some tests on my 2010 Precedent with the original MCOR-2.

Much to my surprise, there was quite a lot of variance, here is a good tip for those that have an XCT Controller.

Connect your laptop to the Controller and start the Alltrax Toolkit software.

Go to Options and enable "Throttle Linearization".

Turn the Key ON and put the FNR in Neutral.

Click on the "Throttle Linearization" Tab.

You now have a high resolution raw "Throttle Monitor", just press the pedal and check your MCOR response.

The first thing I noticed was that the Auto-Cal had made my 80% travel mark equivalent to 100% signal, that is quite a loss of pedal travel on the upper end.

I also noticed that while holding the pedal firmly all the way down, it was very easy to make the throttle move, not surprisingly all the way down to 80%.

I noticed there was a little free-play on the pedal axle that caused the stress on the MCOR, You can easily just change the pressure on your foot and see the signal change.

I took the floor-mat OFF and using what I had on my bench at the time, I came up with this solution, it worked so well that I decided to post.

The jitter on the signal is virtually gone (checked on the Throttle Linearization screen), I also did some slow driving tests and the throttle response is a lot more consistent.

The picture below shows where I applied the pressure to the pedal lever opening to eliminate the free play, I also sprayed dry lubricant (Teflon) on the pedal lever friction surfaces.

I don't know how long it will take before it gets loose again, but the free play is certainly one of the causes of throttle problem.

[Tom47]

Originally Posted by Sergio

I kept thinking about the entire throttle linkage and how it that can torque the MCOR off track, so I decided to run some tests on my 2010 Precedent with the original MCOR-2.

Much to my surprise, there was quite a lot of variance, here is a good tip for those that have an XCT Controller.

Connect your laptop to the Controller and start the Alltrax Toolkit software.

Go to Options and enable "Throttle Linearization".

Turn the Key ON and put the FNR in Neutral.

Click on the "Throttle Linearization" Tab.

You now have a high resolution raw "Throttle Monitor", just press the pedal and check your MCOR response.

The first thing I noticed was that the Auto-Cal had made my 80% travel mark equivalent to 100% signal, that is quite a loss of pedal travel on the upper end.

I also noticed that while holding the pedal firmly all the way down, it was very easy to make the throttle move, not surprisingly all the way down to 80%.

I noticed there was a little free-play on the pedal axle that caused the stress on the MCOR, You can easily just change the pressure on your foot and see the signal change.

I took the floor-mat OFF and using what I had on my bench at the time, I came up with this solution, it worked so well that I decided to post.

The jitter on the signal is virtually gone (checked on the Throttle Linearization screen), I also did some slow driving tests and the throttle response is a lot more consistent.

The picture below shows where I applied the pressure to the pedal lever opening to eliminate the free play, I also sprayed dry lubricant (Teflon) on the pedal lever friction surfaces.

I don't know how long it will take before it gets loose again, but the free play is certainly one of the causes of throttle problem.

Thanks for the great info. I'm printing this and putting it in my manual.

BTW, I installed my harness and XCT48400 in my '99 today. Fun job that was.

The most fun was when I went to back out the gravel drive. I spun the tires with a very gentle push of the pedal. I jacked it back up and noticed the XCT must have been set up for a 0 to 5k control. I switched the pot high and low wires and I don't lose my hat now when I back up!

[Sergio]

Hey Scottyb, did You try that "unfiltered" MCOR test using the procedure on post #14 to see if it shows your signal fluctuation?

[Tom47]

Sergio,

Did you happen to see the additional photos I took of the inside of the MCOR4?

It is under the post titled "MCOR4 Surgery revisited".

[Jkerle]

Sergio, What do you know about the linearized throttle settings? Can you explain what they do?

What I am thinking is your setting the throttle position to a speed? So 6mph is 15% throttle?

[Jkerle]

I guess that cant be right based on the values...

[Jkerle]

I guess if both sets of values are based on percentages it could be..

0-100% throttle and 0-100% speed.