2007 ezgo 36v jerky throttle response

[drewbaby88]

So I’m working on a guys cart for him. It’s a 2007 ezgo DCS. It had a 400a Curtis in it initially I believe. He replaced that with an alltrax nxt 300a controller.

He installed the controller himself. He said that after installing the new controller, the cart “jumps” or “jerks” into motion. He brought it to me to see if I could resolve the issue.

The best way I can describe it is it feels like it has normal acceleration and continual top speed but kind of launches into movement. If you’re easing along and left off the pedal it feels like it “goes dead” or cuts out. I’ve checked the controller and get 12.56v from the 2 throttle terminals. I got .6v-1.3v from the ITS test. I called Alltrax and they felt it was the ITS. Replaced the ITS but it’s still doing the same thing.

What next?

[drewbaby88]

Bump

Could it be a bad solenoid? Motor programmed incorrectly?

[JohnnieB]

Originally Posted by drewbaby88

So I’m working on a guys cart for him.

1. It’s a 2007 ezgo DCS.
2. It had a 400a Curtis in it initially I believe.
3. He replaced that with an alltrax nxt 300a controller.

4. He installed the controller himself. He said that after installing the new controller, the cart “jumps” or “jerks” into motion. He brought it to me to see if I could resolve the issue.

The best way I can describe it is it feels like it has normal acceleration and continual top speed but kind of launches into movement. If you’re easing along and left off the pedal it feels like it “goes dead” or cuts out.

5. I’ve checked the controller and get 12.56v from the 2 throttle terminals. I got .6v-1.3v from the ITS test. I called Alltrax and they felt it was the ITS. Replaced the ITS but it’s still doing the same thing.

What next?

1. The sepex drive in 2007 was a PDS. If it is a DCS it was 1999 or before.
2. The stock controller was 300A.
3. Perhaps it is a NPX?
4. Might be the throttle up ramp is set to high, but the NPX isn't user programmable, so it cannnot be changed.
5. ITS test for an Alltrax controller is: The voltage between the black and white wires to the ITS sensor with everything connected is 10V when pedal is pushed just far enough to make solenoid click and 6V when pedal is on floor. Those voltages are way off, but not sure if you are measuring it right.

If you are truly getting over 12V when solenoid click and it is a DCS cart, Cut off the in-line connector that connects the four wires in the gray cable from the pedal box to the carts wiring harness and butt-splice (or solder joint) the individual wires together and seal with marine grade (waterproof) shrink tube.

[drewbaby88]

Thanks for that info. There are are no VIN plates anywhere. Only serial I can find is on the frame rail under the driver side floorboard.

When he received the NPX controller, it wasn’t programmed. He told me the cart was a 2007. Is it any possibility that the controller was programmed for a regen cart instead of the PDS style?

[drewbaby88]

Originally Posted by JohnnieB

5. ITS test for an Alltrax controller is: The voltage between the black and white wires to the ITS sensor with everything connected is 10V when pedal is pushed just far enough to make solenoid click and 6V when pedal is on floor. Those voltages are way off, but not sure if you are measuring it right.

If you are truly getting over 12V when solenoid click and it is a DCS cart, Cut off the in-line connector that connects the four wires in the gray cable from the pedal box to the carts wiring harness and butt-splice (or solder joint) the individual wires together and seal with marine grade (waterproof) shrink tube.

I measured voltages with both White and Black wires from the ITS connected and it never drops voltage. It goes OL on my meter even set to 200v. It will show 13v or so upon initial pedal press then out of range immediately

If I disconnect the terminals and just measure at the spades at 2 and 3, I get 12.56v constant, from when the pedal is pressed until all the way to the floor

[JohnnieB]

The NPX controllers were more or less plug-n-play replacements for the stock DCS controllers and were fairly docile. The user programmable versions (DCX) could be adjusted for a lot more oomph.

Both the DCS and PDS are sepex (separately excited) drive systems and both have regen braking. DCS was EZGO's first attempt at a sepex drive and there were some issues, so it was replaced by the PDS after only a few years. DCS's were sole from about 1995 thru 1999 and PDS (36V) from 2000 to about 2010 or so. I don't know the exact production run dates.

If the carts wiring harness has a 10-pin connector that plugs directly into the top of the NPX controller, the cart is a DCS. If three plugs from the carts wiring harness plug into an adapter that connects them to the 10-pin connector on top of the NPX, the cart is a PDS. (Also, the F/R of a 2007 PDS would be a rocker switch next to keyswitch on dash.)

------------
If it is a PDS, the 4-pin in-line connector plugs into the PDS to DCX adapter kluge, so it cannot be removed, as suggested for the DCS.

For a PDS, spray clean all the plugs and jacks.

[JohnnieB]

Originally Posted by drewbaby88

I measured voltages with both White and Black wires from the ITS connected and it never drops voltage. It goes OL on my meter even set to 200v. It will show 13v or so upon initial pedal press then out of range immediately

If I disconnect the terminals and just measure at the spades at 2 and 3, I get 12.56v constant, from when the pedal is pressed until all the way to the floor

Replace the battery in your DMM. Shouldn't have more than about 40V at the most.

The throttle wires are not on pins 2 & 3, nor are the spade lugs.

Let's go back to square one and identify the cart and drive system so we are both on the same page.

Post a picture of the controller.

[JohnnieB]

Good grief, I screwed up and mistakenly thought the NPX was a sepex controller. (Calling the cart a DCS may have confused my antique mind.)

The NPX is a series controller, it's the NCX that is the sepex controller.

Let me take a minute or so to get my head thinking about series drives.

[JohnnieB]

Has this controller ever worked in this cart??????

The reason I asked is because there were two flavors of NPX, on for a pot-box throttle and on for a ITS type throttle.

When the pedal is pushed far enough to make the solenoid click, the LED on the NPX ought to flash green four times and then go to a steady green. It it does, it is programmed fo an ITS throttle. Any other number of green flashes at power up and it is programmed for a different type throttle and won't work with a ITS type.

[drewbaby88]

The cart “works” now. It’s just that it’s WOT and no in between. You can’t ease around at all.

Just checked the LED on the controller. Blinks green once then solid yellow/orange color in Forward

It blinks green then steady green in reverse.