TPS or Potetiometer?

truxster · #1 01-31-2008

Well, it's only been a year and 6 months and i think my TPS is already starting to go bad. My truck shifts late into 4th gear and overdrive under acceleration. Sometimes it pops out of OD on the freeway. Anyway, i was wondering if installing a potentiometer would be a cheaper and permanent solution. Has anyone out there done this; If so, how do you like it? Or should i just pay the stealer(dealer) $230.00 for a new TPS annually. I hope the TPS is the problem, I'm pretty sure it is because the truck is doing the same thing when the TPS went out 18 months ago. The trans is almost new. Thanks, good to be back

S_T_U_M_P_M_A_N · #2 02-01-2008

My truck does the same thing and it drives me nuts! The previous owner installed a lockout swith that helps hold it in, but dosn't help get it into od. What is a potentiometer? I'm going to watch this one closley. By the way where is the TPS located?

truxster · #3 02-01-2008

Paul733, the TPS(throttle Postition sensor) is located on the front drivers side of the motor. Look where your throttle cable terminates and pivots on a bell crank. On that bell crank you will see a blk. plastic sensor w/a 3 pin plug attached. The TPS is just a potentiometer that sends a voltage reading back to A control module which tells the transmission when to shift according to your gas pedal position. I heard of some people going to electronic Store and placing a adjustable potentiometer on their dash which allows you to adjust at what speed your transmission upshifts. Their are some drawbacks but i can't remember what they were. Which is why i inquired about it in the first place on this site. Maybe someone will chime in and help us out. Thanks Paul

gkainz · #4 02-01-2008

From what I've read, the downside to the pot on the dash is that if you forget to turn it back down when you slow, you stay in lockup.

I'm fighting the intermittent "shift/lockup/od whenever the hell I feel like it" syndrome right now. TPS is set and checks good. Noise filter is the next step and then (or also) reroute the wiring.

see this thread http://www.dieselram.com/forum/ubbth...e/2#Post292571 and the link in that thread on the tps
edit - copied here http://dodgeram.org/tech/transmissio...TPS_adjust.htm

Joe G. · #5 02-01-2008

There is a thread on the TDR that goes into this in detail including drawbacks at: http://www.turbodieselregister.com/forum...yth-buster.html

You may not be able to read it if you are not a member. That depends on how long ago the most recent post to it was. It's way too long to copy and past here. People who are using a pot really like the way it works.

gkainz · #6 02-01-2008

responses to this TDR thread not visible to non-members ... I let mine lapse last year ...

Am I wrong in my understanding of the pot? Do you just set it and forget it, or must you turn it down to unlock the tc?

infidel · #7 02-01-2008

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: truxster</div><div class="ubbcode-body">Or should i just pay the stealer(dealer) $230.00 for a new TPS annually.</div></div> Or you could go to Napa and by one for $158.

Joe G. · #8 02-01-2008

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gkainz</div><div class="ubbcode-body">Am I wrong in my understanding of the pot? Do you just set it and forget it, or must you turn it down to unlock the tc?</div></div>

I don't use a pot so I'm guessing. From what I remember of the thread you can set it so that it unlocks below a certain speed. However, if you are using an exhaust brake that may be too high for you. In that case you can rig a switch to unlock the TC. I have an old style dimmer switch on the floor to do that in addtion to a single pole double throw switch on the dash to control lockup.

S_T_U_M_P_M_A_N · #9 02-02-2008

I checked my tbs and the voltage was .51, kinda low for idle, but I get the full 3.5 at wide open, and it goes up smooth. My next thought was the cable to transmission. Anyone know the proper adjustment on that? Mine has quit a bit of slack in it, and does not pull the lever completly at the transmission. I tightened it up just a hair, I havn't drove it yet. What do you think??

Ron H · #10 02-02-2008

At full throttle there shouldn't be any slack in the cable.
If there is, you can be burning up the clutches from not enough pressure.