Engine/Transmission (1994 - 1998) Electronics Sources and Assembly

[EGILLILAND]

For fear of highjacking someone else’s thread I'd like to start a new one based from Mr. Durand's potentiometer fix for TPS adjustment.



Ref:



https://www.turbodieselregister.com/forums/showthread.php?t=128962&highlight=picture





My question is, staring at the parts shelf at radio shack for a long period didn't help me much. I understand the "gonculations" to derive associated voltages/resistances. What I don't have a lot of experience with is the hands on assembly of these things. For instance, most of the commercially available components are made to work from a PC board interface... . not a "wired" solution.



So... does anyone have any parts sources that lend themselves to the simple copper wire and solder solutions we need to tap into our trucks TPS wiring harnesses? ... Vice a PC board solution that would work well on a test bench but not very well in the "all weather" hot/cold environment under the hood of our trucks.



Mr. Durand's PVC enclosure was ingenious. Just a simple question... . what are the components (i. e. adapted from pc board components)... . how are the soldered connections made? I could revert back to my teenage days of installing friends stereos, just globbing enough solder between two components until they stick …. . doesn't sit well w/my now 40+ "maturity".



Bottom line... can anyone help me bridge the theory w/practice? I want to make the component the right way w/the right parts. After a couple hours of "googling" I haven't really found anything that looks right.



Thanks in advance to all.



Cheers,



Gill

 

[Joe G.]

I solder all connections to components or sockets for components in any electrical modifications I do. For things that attach to removable objects like the dashboard or my switch panel I use plug connector in the wireing.



There is very little current in the TPS circuit so you don't need a big wattage pot. That may be one of the reasons it's prone to failure. Makeing a mount like Howard's or some other way is not all that hard. A little bit of creativeness may be needed.

 

[Howard Durand]

Gill,



There are good sources for electrical and electronic components that don't require circuit boards. Unfortunately, Radio Shack is not one of them. I have been able to acquire a number of standard potentiometers on e-bay to experiment with.

I prefer using the multi turn pots with a turn counting, lockable dial. You can also use a single turn pot with a knob and pointer.



The circuit itself is a simple voltage devider, which apparently you have figured out, that allows you to adjust the TPS signal voltage that is applied to the PCM.

The one that I am using now completely replaces the TPS and applies a constant, set voltage to the PCM.

The previous experiment, the one I had mounted in the PVC fittings, used a potentiometer in the ground leg of the TPS wiring to make the closed throttle TPS voltage adjustable. It worked well but I am happier with the total TPS replacement.



What I am using now is mounted inside the cab so I can make changes as I please. I completely cut the TPS loose from the PCM and fed the wires to where they can be connected to the pot.



With the TPS replacement scheme, you lose "kickdown" capability, either by foot or under load. I use a foot operated dimmer switch for that purpose.

With the pot in the ground circuit, the TPS signal still follows the throttle and you retain the kickdown capability but OD shifting was still unpredictable.



If you decide to try one of these methods and need any help, let me know.



Howard

 

[EGILLILAND]

Thanks for for jumping in Howard, I do appreciate it.



Any other web-based electronics sources you'd recommend to our forum users would be cool.



Can't wait to ask from another thread so I guess I'll risk highjacking my own thread... ...



So to clarify for me... the slow one in the group... it sounds like you've basically replaced your TPS w/a potentiometer... . yes? Did you still include the capacitors for noise filtering?



Pretty neat when these simple solutions provide sooooo much relief. Thanks to you from all of us on the forum.



Cheers,



Gill

 

[Howard Durand]

Thanks for the ego boost Gill but a fellow who calls himself Ridesamule is the one who thought of this.

Joe G. suggested the resistance in the ground wire for adjusting TPS voltage.

I have tried them both and, for my purposes, prefer replacing the TPS. The drawback to that is loss of kickdown.

As far as availability of components, I have purchased parts from Allied Electronics and Mouser Electronics. Both of them have large catalogs. The trouble with them is the components are expensive and shipping is high.

I have found most of what I need on eBay. The problem with that is I wind up with more than I need. I have several 2K and 5K, 10 turn potentiometers with turn counting dials that are excess. If you want a set, let me know.

 

[PKemp]

Gill,



Another good place to find electronics parts is www.jameco.com. They have evrything you need, you can buy single pieces and the prices are extremely reasonable. They'll even send you a free catalog.

But take Howard up on his offer. He probably has boxes of experimental parts laying everywhere.