Potentiometer

[rcb280z]

So just for SAG's I decided to install the "pot" everyone's talking about. I ordered one thru zcardepot for 4 bucks. Wired it up. Simple, took maybe 20 minutes. Half of that was setting up soldering iron, etc. Installed it in the CTS harness, again, simple. Started it up and almost immediately it started to stumble. I figured I had set it wrong and turned the knob on the pot the opposite way. It got worse. Had to throttle it to keep it running. I turned the knob back and forth a couple of times with the same results. I disconnected it from the CTS harness, reconnected the original harness, started it and it ran fine. The reason I installed it, outside of curiosity, was to see if it would help with the start up on warmer days. Cold days are perfect, fires right up. But after sitting over night, then trying to start it first thing in the morning it's "harder" to get started. 2 to 3 tries. The pot did help with that warm morning start up though. It started almost immediately. So now I know I don't have that "lean" running condition that I've read a lot about. And that's why I have to play around with FI before emissions testing every time I have to smog it. So I'm surprised that there was no effect for DC871F when he installed it on his ZX. Should have shown something. Anyway, here's a pic of the pot from zcardepot.

Oh forgot to mention, It was getting too much fuel. Thats why the stumble. You could smell it running real rich.

Edited January 17, 2018 by rcb280z
forgot something important

[siteunseen]

I'm sorry Bob. At least you didn't spend too much and can be of help to others in the future.  Bummer, but we learn from you.

Cliff

I got me a Bottle of Patron for this winter wizz storm. 

I'm chasing my dog around trying to lick his nose like he does me every frickin morning.

[rcb280z]

Yeah it's not a big deal. It answered some questions, so not a loss. 

2 minutes ago, siteunseen said:

I'm chasing my dog around trying to lick his nose

Now where do you think his nose has been?

 

3 minutes ago, siteunseen said:

got me a Bottle of Patron

Just one! Light weight 

[siteunseen]

He's started an ALADOG program around here.

I got a smaller bottle, my Mom always said I was "half drunk". Can't let her down now.

 

[Zed Head]

5 hours ago, rcb280z said:

So just for SAG's I decided to install the "pot" everyone's talking about. I ordered one thru zcardepot for 4 bucks. Wired it up. Simple, took maybe 20 minutes. Half of that was setting up soldering iron, etc. Installed it in the CTS harness, again, simple. Started it up and almost immediately it started to stumble. I figured I had set it wrong and turned the knob on the pot the opposite way.

Did you measure resistance across the terminals?  Should have been about zero at one end of the rotation.

And did you solder two terminals together as one leg of the circuit?  I don't think that you need to do that.  Just measure resistance across two terminals that show zero and a higher number,with knob rotation, and use those two for the circuit.  We're not really using it as a potentiometer, it's really a rheostat.

http://www.resistorguide.com/rheostat/

Edited January 17, 2018 by Zed Head
Perfecting...

[rcb280z]

10 hours ago, Zed Head said:

it's really a rheostat.

This is true.

 

10 hours ago, Zed Head said:

Did you measure resistance across the terminals? 

No I did not. Started to panic, thought I screwed something up, so I put everything back to the way it was. Now that I've had time to think about it I think I know what may have happened and will test it again. It came to me in the middle of the night, woke up thinking about it. Maybe the other connector was not connected properly, really didn't have to be unplugged, but possible. For some reason it woke me up so there may be something there to investigate. 

[rcb280z]

UPDATE

So, I connected the "pot / rheostat" again and this time I got different results. So my hunch, at 2 a.m., was correct. Guess "maybe" the connector without the "pot" was not connected. It's the only reason I can come up with as to why things happened the way they did. Took some measurements today, they are as follows.

 

Pot in closed position

fully open position

CTS cold reading

CTS ECU harness

CTS warm reading

And I also measured 1.82 across the CTS ECU harness after warm.

Edited January 17, 2018 by rcb280z

[siteunseen]

Dummy here going to ask, does it run better?  I hope so.

[rcb280z]

Yeah I can smooth out the idle for sure so I expect my drive will be fun. Going for a drive soon. Will report back. So the plan is to set her up to pass emissions testing standards (when its time) and dial her in to run good the rest of the time. 

[rcb280z]

Went for a drive. I guess my expectations were a little too high, maybe? It's not a considerable amount but maybe a slight measurable increase in performance. I don't expect turbo power here. Just something more than I did feel. 

What kind of increase in performance has everyone noticed, or did you?

Edited January 17, 2018 by rcb280z

[Zed Head]

It's really only meant to get rid of mid-range hesitation or intake firing/popping.  At open throttle, the ECU dumps a lot (27%) of extra fuel.

[rcb280z]

Oh okay, I understand. I did get it to smooth out the idle some though. 

Wow 27%? That's a lot.