2007 EZGO PDS Jerking / Surging

[Mancebo]

I have a 2007 EZGO pds. It has 3 year old batteries that are good. Pack is consistently over 38.2 and I rarely use over 2 or 3 miles a weekend. It stays plugged in when it is not in use. It has a DCX(non - programmable) upgrade and I use a DPI charger. I was on the road for work and it sat on the charger for 2 weeks. Never had an issue before today. Used it for a good 30 minutes and parked and it ran perfect. Then when I went to put it back in the parking space it was surging and jerking all over. I will describe the symptom as best I can. When I went to give it pedal, it felt like it went 100% throttle then immediately went off, then back then off. All while I had 10-20% throttle. I checked the DCX controller and it was green light constant. I live in Indiana, and the cart is covered. We had no rain, and I did not go through any puddles. I messed with the throttle, the tow switch, the fw/rev swith (by the way it does it in Fw or Rev) turned off and on, checked all the battery terminals, and nothing changed. I will not be by the cart until next weekend, but if there is something I should look at, please let me know.

Thank you in advance for your help.

[JohnnieB]

A DCX is programmable, the NCX is not.

Lift rear tires off ground and put on jackstands.

Place Run/Tow into Tow and connect a voltmeter between Pin-3 & 4 of J4 in the stock wiring harness where it plugs into the PDS to DCX adapter. (Push the test probes into the backside of J4 Pins 3 & 4 with everything connected)

Place Run/Tow into run and other switches like you were going to be driving cart.

When pedal is pushed just far enough for solenoid to click, you should read 10V, or very close to it.

Slowly push pedal down. The voltage should smoothly decrease.

Pedal up is 10V and pedal down is 6V, so if you push down 25%, it should be about 9V, 50% about 8V, 75% about 7V.

The DCX has different throttle response curves, so the % vs voltages will be a bit off, but the decrease should be smooth when you push pedal slowly.

IF it drops rapidly or erratically, disconnect the in-line connector between the pedal box and the cart's wiring harness and spay clean the contacts.

[Mancebo]

Johnnieb,
I was getting nervous since you or scootyb hadn't responded. I will do as recommended. Based on all the research it sounds like ITS. If I order one does it make a difference that i have a different controller? I will DEFINITELY check the in line connector between the box and carts wiring harness. Looks like I will be taking the volt meter with me to the campground. LOL. Thanks for the reply.

[JohnnieB]

The ITS sensor is identical for all controllers with a ITS throttle input.

The tricky part is that the ITS sensor is only a part of the ITS circuit and the rest of it is in the controller, plus the wires and connections that connect the ITS sensor to the controller.

The pedal up and pedal down voltages are different for different makes and models of controllers, but for all Alltrax controllers it is 10V up and 6V down, measured between the black and white wires.

The ITS sensor has a circuit board in it (schematic attached) and the potting compound occasionally develops a hairline crack along the edge of the board. If that happens, all it takes is humidity to make it do mysterious things.

On the other hand, there are several connectors the throttle signal passes through, and all of them are susceptible to humidity, moisture and corrosion too.

[Mancebo]

Is the connector from the ITS that i should inspect located in the box with the its. OR is it under the cart? I only ask as my cart has a diamond plate floor cover and it is "not fun" to remove. But if that connector is there, it will come out over the weekend unless I should be looking somewhere else.

[JohnnieB]

Originally Posted by Mancebo

Is the connector from the ITS that i should inspect located in the box with the its. OR is it under the cart? I only ask as my cart has a diamond plate floor cover and it is "not fun" to remove. But if that connector is there, it will come out over the weekend unless I should be looking somewhere else.

IIRC, the connector comes through the frame in front of the battery pack.

You ought to be able to get to it from under the cart.

[Mancebo]

Johnnieb,
Checked every connectiin. ITS, dcx connections, battery terminals. When i tightened the comnections to the motor and the symptons disappeared for a 10 minute cruise. It feels like it goes 100% throttle for 1 second then cuts off. This happens until about 10mph. The cart axtually feels stronger during the surging than when it hasn't surged. Ordered a new ITS to see if that helps. Any advice while the cart is apart would be greatlt appreciated.

[Mancebo]

Update. Now the symptoms only happen in fwd. Reverse is fine. Any ideas?