Notes of POT mod as TPS

BgBlDodge

BgBlDodge

Hates hippies
Joined
May 7, 2007
Messages
16,647
Got the TV setup so tranny is shifting at 1800rpm like before on the 1-2 shift and 2-3 happens around 1600-1700. Turning the POT one way or the other drastically affects the shift points. One way it holds the shifts out to 2500rpm and the other way it won't shift unless you let off the throttle completely. Only thing though is that it won't lock up and it won't hit OD. I can manually force lock up with my lock up switch but I can't get it in to OD. I'm gonna go put some fuel in the truck and jack around with it some more.
 
Here's how my POT is hooked up right now:

Pin 1 or 3-black/yellow tracer
Pin 2-blue/black tracer
Pin 1 or 3-blue/white tracer

I'm told it needs to be like this:

Pin 1-black/yellow tracer
Pin 2-blue/yellow tracer
Pin 3-blue/white tracer

Only problem is is I don't have a blue/yellow tracer in my factory 24v wiring harness. I only have the following colors:

Green/Blue Tracer
Black/Orange tracer
Black/Blue tracer
Black/yellow tracer
Blue/Black tracer
Blue/White tracer

I have tried changing around pins 1 and 3 with no success. I still can't get the computer to hit lock up or OD. All the other shift points are working fine. Just not lock up or OD. Maybe I have to buy a 12v TPS?
 
The way you have it is correct. Check your connections

Pin 1 black/yellow tracer

Pin 2 goes to Blue/black tracer.


Pin 3 goes to Blue/white tracer.

Not blue/yellow tracer

You need to find out if the computer is giving the signal to the OD solenoid to engage. If the signal is given then your problem might be the solenoid. If you are not getting that signal your issues are 1) Bad wiring or wrong wires 2) Bad TPS.
 
Here are pics of both conector views and wiring color.
 

Attachments

  • 12v tps.gif
    12v tps.gif
    10.8 KB · Views: 32
  • 24v tps.jpg
    24v tps.jpg
    32.6 KB · Views: 27
So I've got the right wire colors for this. Looks like it's time to pull out the volt meter and make sure the right voltage is getting sent where it should.
 
SmokinRamMike said:
You need to find out if the computer is giving the signal to the OD solenoid to engage. If the signal is given then your problem might be the solenoid. If you are not getting that signal your issues are 1) Bad wiring or wrong wires 2) Bad TPS.
Click to expand...

I've got a light on my dash that lights up when the computer tells the tranny to lock/unlock. It's not lighting up and the tranny isn't locking up so I know the computer isn't sending out the signal. Question now is it a bad potentiometer, loose wiring, or on a 24v p-pump conversion you have to use the 12v TPS. I don't understand why you would since the 12v's came with 47re's and folks have installed a potentiometer in place of their TPS's with no problems but maybe the 12v and 24v PCM are different enough that it needs the TPS instead of a POT.
 
So if I am understanding you, you are using your 24v APPS wired to a POT that then shifts your transmission? I would have just found a TPS and wired in those three wires. Is there any pictures on how you set this up or wired it up on your truck?

I took a look at some of the pics on your photo bucket but I dont see any wiring.
 
Last edited:
No. I have no 12v TPS or 24v APPS. Just a potentiometer. Do a search for POT mod. It takes the place of the TPS on a 12v application and completely eliminates it. Since we've essentially turned our trucks in to 12v's this should work just the same.
 
Finally got this thing sorta dialed in and working. Lockup in 3rd I can get anywhere from 40mph-55mph depending on the position of the POT but I have to wrap first gear out to 2400rpm before it shifts. I have gotten OD a couple of times but I can't get enough wide open road and enough speed built up to get it dialed in.

Another note is that when I take my foot off the gas when it's locked it stays locked up, when I tap the brakes it unlocks and locks back up even with my foot still on the brake, once it gets down to about 30-35mph it unlocks and stops nicely.

I've got a TPS coming from autozone ($132) that I'm going to go ahead and get just in case I can't dial this POT in fully but I won't install it till I can get more seat time with this thing.

Oh and this thing needs a GSK kit something terrible LOL.
 
I set the POT at 3.56v tonight and went for a spin. At first, 1-2-3 were all shifting around 1800-2100rpm. Perfect. Lockup happened at 55mph and it unlocked at 52mph. Perfect. OD wouldn't engage. Dang it. So I floored it and wrapped it up pretty good (stock GSK sucks) and let off. Now 1st is running up to 2400rpm, 2-3 stayed about the same, lock up is back down to around 45mph and won't unlock till 32-35mph, and OD now works. Checked the voltage again and it's still 3.56v. This was all done after I removed my lock up switch completely.

So basically, the POT mod won't work for a 24v P-pump conversion. The PCM reads a lot more information from the TPS other than a set voltage. So now I'm trying to figure out how to bolt a TPS sensor up to a manual transmission linkage. I can rotate the sensor far enough forward to make everything touch and work together (if you've seen a manual and auto linkage next to each with the TPS sensor you'll understand what I'm saying) but the bolt holes don't quite line up. I think I'm going to drill a few new holes and bolt it that way, cut the plug off the MAP sensor (like it does anything anymore LOL ) and call it good.
 
any updates on this? i have been reading about this mod for a wail and i figured the same thing that is if it worked in place of the 12v tps that it would wrk for our trucks but after reading this thread it doesnt appear so. so what my question...i have a bracket on my pump just no sensor, is there somewhere that i can just get the sensor part of the bracket?
 
I never could get mine to work so I just bought the sensor from autozone for $130.
 
CL2000 said:
Mine works fine. Ill post details later tonight
Click to expand...

thats what i was looking for! i just want one good possibility that it might work and i will try it. my truck is a 98.5 that looks just like yours but with 35's and no stack yet.

BgBlDodge said:
I never could get mine to work so I just bought the sensor from autozone for $130.
Click to expand...

ya im just trying to get out of having to buy a sensor. i sponsored this build by selling my quad(500) and vp(1350) so i dont have unlimited resources. i got lucky and sold my vp to a guy and installed it for him and got more than i payed for the vp so i was happy but with a custom cam things are guna be tight...what pot did you use? mabe that was the problem and you just happened to get a bad one? just an idea...
 
I was on the same budget. Sold my quad and VP to the same guy and a spare VP to finance the build.
 
CL2000 said:
Mine works fine. Ill post details later tonight
Click to expand...

can you post details on this mod? im looking to do it within this week. i am wraping up the p-pump swap and i need to do something to get the tranny to shift in to od right without using a 136$ 12v tps...

thanks for the help!
rory
 
some 98 cummins said:
can you post details on this mod? im looking to do it within this week. i am wraping up the p-pump swap and i need to do something to get the tranny to shift in to od right without using a 136$ 12v tps...

thanks for the help!
rory
Click to expand...


X2 on what he said.
 
i will have to get a picture but i was able to use the 24v tps, and all the original throttle linkage i just made a link from it to the p7100 throttle arm. I bolted the whole throttle linkage setup on the side of my ppump. no wireing or messing with cable to get it to work.
 
You must log in or register to reply here.
Back
Top