2005 Precedent - surges

trigger1937 · 07-26-2012, 03:58 PM

Driver33b,...I know that your posts are over a year old but they have provided a lot of information and my problem with my 2008.5 CC IQ are just like what you have had. My problem is being an Engineer I always want to know why things fail. I must have searched and read a hundred posts before I got to yours. The "Suggested Diagnosis" has been either,.."MCOR",.."Speed Sensor",..or the "Batteries". I've found people with the same problem description of "Herky-Jerky",..or cut out/cut in,..or just stutter Step.

The MCOR contains only two components, a micro switch and a Potentiometer. There are two wires to the micro switch and the result is either open or closed circuit. There are three wires to the Potentiometer, Ground- and +48 volts and the output signal wire which will contain any voltage from 0 to +48. When switches fail they are 99% of the time "OPEN" or intermittent contact. This failure mechanism would produce a 100% on---or---OFF function and would not be the action that happens in my cart. Mine can be running at any speed depending on the petal and all of a sudden drop in speed by 2-to 3 mph. It does not shut off or just "Cut out". So I don't think the problem is the switch,..but there is also an easy test for that.

There are two typical failures of potentiometers,...1. The resistor fails due to overheating and cracks and losses 100% connection. 2. The wiper contact that connects to the resistor makes and breaks contact and produces an intermittent connection. The result would be a "Sharp" 100% drop in voltage or virtually an "Open" connection. The voltage to the controller would instantaneous drop to zero. This would cause the cart motor to totally shut off and would not just be a slowdown in speed but it would try to come to a halt. This would not fit the description of my carts action.

Finally we have the batteries. Mine are 4 - 12volt units about 3+ years old. Typically after an overnight charge they measure 12.7, 12.7, 12.66, 12.68, so they are pretty balanced. My question is,..What mechanism is there in a chain of batteries that can cause the "Herky-Jerky" action? I can see that under load one or more cells of the battery will have a problem passing the current demand,..But I don't see how or why it would be intermittent and "Come and GO' at random. The only thing I can think of is the long term failure mechanism of these batteries,..which it that so many particles have fallen off of the plates that the inside bottoms are becoming full and short out two plates and the cell voltage drop by 0.100 volt ( I don't know how much each plate produces as it may be 0.200 volts). This would cause a sudden drop of the voltage and current and account for the sudden reduced speed. However,..as I drive the car,.. the speed will come back which would make you believe that the short in the bottom was just temporary,..and somehow the tiny particle that produced the short was "Burnt up" and blew away.

I would welcome all comments because I really want the answer. I don't want to replace the MCOR and then the Speed Sensor and then find out all along that the problem is with the batteries.

My next task will be to adds some wires to the + and - terminals and measure the voltage as I drive. If I see the sudden drop I will have one answer

TahoeDawgZ71 · 07-26-2012, 07:31 PM

Your batteries won't cause a "herky jerky" motion. Neither will your speed sensor. When a speed sensor fails it only knows one speed.... SLOW. Do a simple speed sensor test to confirm it works. Push the car and see if it attempts to slow itself as if it was rolling down a hill. If it does, the sensor works. The MCOR will cause the exact problem you describe. The potentiometer will develop "crap" on the contacts, for lack of better description, and periodically will not make a good connection. This causes the resistance to change, which causes the speed to change. I see it every day.

driver33b · 07-26-2012, 08:21 PM

Thank you for your kind words.

I can't add to my cure or diagnose more than my cure....I can only confirm that my cart is still a pleasure to drive with constant and predictable performance.

I CAN tell you of something that may be of interest or be totally dismissed.....just more fuel and speculation? Sorry about that.

The time line now looks abit suspicious to me. Oct. 14 2011 fitted 6x8s, on 11/31/11 I noted that the charger had a 'newish' smell...or over heating smell....I took no action as the BP was still up at 51.2v (12hrs) after charging. 11/29/11 I fitted a Digital Battery Meter (C&N brand [cheap and nasty-Chinese]), which is still working fine, then on May 10 2012 I noticed the charger had not come on/finished its cycle....the front fuse had half melted....I opened it up and noticed some singe marks around the mounting bolts on the heat sink....so I replaced both components.

The charger had been dropped before my ownership and I had had it apart and panel beated the case straight and 'inspected' the workings when I first got the cart (Feb.20 2009). All looked and performed normal for the following 3 years until May this year, other than the 'hot' smell.

I know other very reputable (and respected) members here recommended swapping out the OBC with the battery change....I have taken the wait and see path....leaving mine stock 3.0 ver.that was the cart. Touch wood, all is good so far.

Sorry I am not confirming anything, but instead adding speculation.

trigger1937 · 07-27-2012, 12:43 AM

Tahoedawg,...thanks for the support and info. I have seen a couple of posts where similar Herky-Jerky action dissapeared after new batteries were install,..i.e. like the posts that driver3b has made that led me to believe it had to be a battery problem. However, I have had a hell of a battery history,..but thanks to my local CC dealer he has let me have the "Choice" of all the 12 volt batteries he has to return for core credit. I started out with 4 2010 batteries in a cart that came off a golf course and over 4 + months 3 of them failed with one cell going bad. Over that period I've finally found 3 USED batteries that seem to match the one I have left. I now have 4 that will charge to 12.68, 12.70, 12.72, and 12.76. My wife took the cart today to play 18 holes and took a partner with her. When she got home I checked the batteries and all were above 12.6 to 12.7 after 5 hours on the course so I know they hold up under a load.

I've done the speed sensor test several time and I can't move the cart with normal pressure. If I'm on a hill the alarm will sound before the cart starts to move.

I've been trying to get a MCOR out of Plum Quick but it turns out that Robby can't get the swap outs from CC anymore. Seems that a couple of dealers compained about him selling "Used Parts". They told him they were either going to offer them to dealers or scrap the entire lot. Since you have some good connections,..maybe you could get a few of them. These are just pulled parts from carts that are being converted to GAS and since they have been installed once they can't be sold as new,..and many dealers don't want to mess with any potential problems no matter what the savings would be. It is not worth their time or the potential customer relations.

I've seen another post from someone that actually cut his MCOR apart and found and fixed the problem. I guess that is my next step.

TahoeDawgZ71 · 07-27-2012, 01:06 PM

Batteries won't fix the problem if it's exactly as you described.... While on the throttle, your voltage should drop, hence dropping your speed. Your batteries are not going to increase, decrease, and increase, over and over again while they're loaded and cause a jerky feeling... They'll decrease voltage and maintain a slow speed. As for Club Car, yes your speculations are correct. They're currently in the process of moving their entire used car and service department to their main facility a couple miles away. It's putting a hurting on us as well as far as getting used parts. The stuff they threw away would make you sick.

trigger1937 · 07-27-2012, 07:13 PM

TahoeDawg,...You would think they would understand the current economic crisis and how many people are out of work and how little money we have left. Don't that know that if they offered "Used" parts at half price the majority of people with money would still opt out for the NEW parts. I bet that less that 15 % would order used parts,.. no matter what it was....i.e. motors, MCOR, switches, OBC, controllers,..etc. especially if they only came with a 30 day or no warranty at all. IF we were all as well off as we were before all this crap started happening,..that would be a different story.

On a totally different topic,.. I just noticed that your in Agusta, GA.,,and that brings back a lot of memories. In early 1960 I spent 3+ months in Fort Gordon, GA, being retrained in Helicopter/light planes communications and then shipped out (yes it was a military ship) to Germany for 2+ years. I had a good friend with us that lived in a little town south of Agusta called "Brooklet" GA. and we used to spend the weekends with his family and Saturday night at the local dive. These were some of the best years. I was there when the "Berlin Wall went UP". What a nightmare.

TahoeDawgZ71 · 07-28-2012, 07:42 AM

Quote:

Originally Posted by trigger1937

On a totally different topic,.. I just noticed that your in Agusta, GA.,,and that brings back a lot of memories. In early 1960 I spent 3+ months in Fort Gordon, GA, being retrained in Helicopter/light planes communications and then shipped out (yes it was a military ship) to Germany for 2+ years. I had a good friend with us that lived in a little town south of Agusta called "Brooklet" GA. and we used to spend the weekends with his family and Saturday night at the local dive. These were some of the best years. I was there when the "Berlin Wall went UP". What a nightmare.

Awesome! Yes sir, I'm right here in the middle of it. The home of the Masters and the home to both E-Z-GO and Club Car.

erict · 07-28-2012, 11:53 AM

Quote:

Originally Posted by TahoeDawgZ71

Awesome! Yes sir, I'm right here in the middle of it. The home of the Masters and the home to both E-Z-GO and Club Car.

And the home of our #1 CC Technician....

TahoeDawgZ71 · 07-28-2012, 03:16 PM

Quote:

Originally Posted by erict

And the home of our #1 CC Technician....

Thank you sir

erict · 07-28-2012, 09:45 PM

Quote:

Originally Posted by TahoeDawgZ71

Thank you sir

You deserve it and your time and knowledge is greatly appreciated by all of us. I work at a auto dealership and have 22 years experience in the parts department and know what value a good technician is.

07-26-2012, 03:58 PM	#11
trigger1937 Gone Wild Join Date: May 2009 Posts: 230	Re: 2005 Precedent - surges Driver33b,...I know that your posts are over a year old but they have provided a lot of information and my problem with my 2008.5 CC IQ are just like what you have had. My problem is being an Engineer I always want to know why things fail. I must have searched and read a hundred posts before I got to yours. The "Suggested Diagnosis" has been either,.."MCOR",.."Speed Sensor",..or the "Batteries". I've found people with the same problem description of "Herky-Jerky",..or cut out/cut in,..or just stutter Step. The MCOR contains only two components, a micro switch and a Potentiometer. There are two wires to the micro switch and the result is either open or closed circuit. There are three wires to the Potentiometer, Ground- and +48 volts and the output signal wire which will contain any voltage from 0 to +48. When switches fail they are 99% of the time "OPEN" or intermittent contact. This failure mechanism would produce a 100% on---or---OFF function and would not be the action that happens in my cart. Mine can be running at any speed depending on the petal and all of a sudden drop in speed by 2-to 3 mph. It does not shut off or just "Cut out". So I don't think the problem is the switch,..but there is also an easy test for that. There are two typical failures of potentiometers,...1. The resistor fails due to overheating and cracks and losses 100% connection. 2. The wiper contact that connects to the resistor makes and breaks contact and produces an intermittent connection. The result would be a "Sharp" 100% drop in voltage or virtually an "Open" connection. The voltage to the controller would instantaneous drop to zero. This would cause the cart motor to totally shut off and would not just be a slowdown in speed but it would try to come to a halt. This would not fit the description of my carts action. Finally we have the batteries. Mine are 4 - 12volt units about 3+ years old. Typically after an overnight charge they measure 12.7, 12.7, 12.66, 12.68, so they are pretty balanced. My question is,..What mechanism is there in a chain of batteries that can cause the "Herky-Jerky" action? I can see that under load one or more cells of the battery will have a problem passing the current demand,..But I don't see how or why it would be intermittent and "Come and GO' at random. The only thing I can think of is the long term failure mechanism of these batteries,..which it that so many particles have fallen off of the plates that the inside bottoms are becoming full and short out two plates and the cell voltage drop by 0.100 volt ( I don't know how much each plate produces as it may be 0.200 volts). This would cause a sudden drop of the voltage and current and account for the sudden reduced speed. However,..as I drive the car,.. the speed will come back which would make you believe that the short in the bottom was just temporary,..and somehow the tiny particle that produced the short was "Burnt up" and blew away. I would welcome all comments because I really want the answer. I don't want to replace the MCOR and then the Speed Sensor and then find out all along that the problem is with the batteries. My next task will be to adds some wires to the + and - terminals and measure the voltage as I drive. If I see the sudden drop I will have one answer
trigger1937 Gone Wild Join Date: May 2009 Posts: 230

07-26-2012, 07:31 PM	#12
TahoeDawgZ71 revolutiongolfcars.com Join Date: Mar 2010 Location: Golf Car Capital of The World... Augusta, Georgia Posts: 10,224	Re: 2005 Precedent - surges Your batteries won't cause a "herky jerky" motion. Neither will your speed sensor. When a speed sensor fails it only knows one speed.... SLOW. Do a simple speed sensor test to confirm it works. Push the car and see if it attempts to slow itself as if it was rolling down a hill. If it does, the sensor works. The MCOR will cause the exact problem you describe. The potentiometer will develop "crap" on the contacts, for lack of better description, and periodically will not make a good connection. This causes the resistance to change, which causes the speed to change. I see it every day.

07-26-2012, 08:21 PM	#13
driver33b Getting Wild Join Date: Feb 2009 Location: Sydney NSW Posts: 92	Re: 2005 Precedent - surges Thank you for your kind words. I can't add to my cure or diagnose more than my cure....I can only confirm that my cart is still a pleasure to drive with constant and predictable performance. I CAN tell you of something that may be of interest or be totally dismissed.....just more fuel and speculation? Sorry about that. The time line now looks abit suspicious to me. Oct. 14 2011 fitted 6x8s, on 11/31/11 I noted that the charger had a 'newish' smell...or over heating smell....I took no action as the BP was still up at 51.2v (12hrs) after charging. 11/29/11 I fitted a Digital Battery Meter (C&N brand [cheap and nasty-Chinese]), which is still working fine, then on May 10 2012 I noticed the charger had not come on/finished its cycle....the front fuse had half melted....I opened it up and noticed some singe marks around the mounting bolts on the heat sink....so I replaced both components. The charger had been dropped before my ownership and I had had it apart and panel beated the case straight and 'inspected' the workings when I first got the cart (Feb.20 2009). All looked and performed normal for the following 3 years until May this year, other than the 'hot' smell. I know other very reputable (and respected) members here recommended swapping out the OBC with the battery change....I have taken the wait and see path....leaving mine stock 3.0 ver.that was the cart. Touch wood, all is good so far. Sorry I am not confirming anything, but instead adding speculation.

07-27-2012, 12:43 AM	#14
trigger1937 Gone Wild Join Date: May 2009 Posts: 230	Re: 2005 Precedent - surges Tahoedawg,...thanks for the support and info. I have seen a couple of posts where similar Herky-Jerky action dissapeared after new batteries were install,..i.e. like the posts that driver3b has made that led me to believe it had to be a battery problem. However, I have had a hell of a battery history,..but thanks to my local CC dealer he has let me have the "Choice" of all the 12 volt batteries he has to return for core credit. I started out with 4 2010 batteries in a cart that came off a golf course and over 4 + months 3 of them failed with one cell going bad. Over that period I've finally found 3 USED batteries that seem to match the one I have left. I now have 4 that will charge to 12.68, 12.70, 12.72, and 12.76. My wife took the cart today to play 18 holes and took a partner with her. When she got home I checked the batteries and all were above 12.6 to 12.7 after 5 hours on the course so I know they hold up under a load. I've done the speed sensor test several time and I can't move the cart with normal pressure. If I'm on a hill the alarm will sound before the cart starts to move. I've been trying to get a MCOR out of Plum Quick but it turns out that Robby can't get the swap outs from CC anymore. Seems that a couple of dealers compained about him selling "Used Parts". They told him they were either going to offer them to dealers or scrap the entire lot. Since you have some good connections,..maybe you could get a few of them. These are just pulled parts from carts that are being converted to GAS and since they have been installed once they can't be sold as new,..and many dealers don't want to mess with any potential problems no matter what the savings would be. It is not worth their time or the potential customer relations. I've seen another post from someone that actually cut his MCOR apart and found and fixed the problem. I guess that is my next step.
trigger1937 Gone Wild Join Date: May 2009 Posts: 230

07-27-2012, 01:06 PM	#15
TahoeDawgZ71 revolutiongolfcars.com Join Date: Mar 2010 Location: Golf Car Capital of The World... Augusta, Georgia Posts: 10,224	Re: 2005 Precedent - surges Batteries won't fix the problem if it's exactly as you described.... While on the throttle, your voltage should drop, hence dropping your speed. Your batteries are not going to increase, decrease, and increase, over and over again while they're loaded and cause a jerky feeling... They'll decrease voltage and maintain a slow speed. As for Club Car, yes your speculations are correct. They're currently in the process of moving their entire used car and service department to their main facility a couple miles away. It's putting a hurting on us as well as far as getting used parts. The stuff they threw away would make you sick.

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07-27-2012, 07:13 PM	#16
trigger1937 Gone Wild Join Date: May 2009 Posts: 230	Re: 2005 Precedent - surges TahoeDawg,...You would think they would understand the current economic crisis and how many people are out of work and how little money we have left. Don't that know that if they offered "Used" parts at half price the majority of people with money would still opt out for the NEW parts. I bet that less that 15 % would order used parts,.. no matter what it was....i.e. motors, MCOR, switches, OBC, controllers,..etc. especially if they only came with a 30 day or no warranty at all. IF we were all as well off as we were before all this crap started happening,..that would be a different story. On a totally different topic,.. I just noticed that your in Agusta, GA.,,and that brings back a lot of memories. In early 1960 I spent 3+ months in Fort Gordon, GA, being retrained in Helicopter/light planes communications and then shipped out (yes it was a military ship) to Germany for 2+ years. I had a good friend with us that lived in a little town south of Agusta called "Brooklet" GA. and we used to spend the weekends with his family and Saturday night at the local dive. These were some of the best years. I was there when the "Berlin Wall went UP". What a nightmare.
trigger1937 Gone Wild Join Date: May 2009 Posts: 230

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