My question is are you able to install a TPS delete kit (potentiometer) on a non lock up A518 transmission (2 wire) out of a 1992 w-250?

My application/truck is a early 1991 w-250 it originally had a 3 speed 727. During the restoration of the truck I found a A518 non-lock up transmission for a good price and installed it. My plan was to just wire the Over Drive to a switch on the dash.

I've seen these TPS delete kits from Geno's and other places for a reasonable price. An I thought it might be nice not to hit a switch every time. But...The TPS delete kit looks to have 3 wires and plugs into the TPS wiring connector. I don't have either, I only have the pig tail coming out of the trans with two wires. So will the TPS delete work? Does anyone have a wiring diagram of where the OEM TPS wires go? Or a wiring diagram of a TPS delete? so I can come up with a game plan if no one has done it before....

Thanks,

 

Without looking at my truck, and it's been a while since I've dealt with the TPS, I can't remember how many wires but it does seem like only two. And it is possible to run a potentiometer on the A518 for OD but I assume this is for a different application? Not being a transmission guy (there's a few members here that are really good at that stuff) I couldn't tell you how to wire it up but when I used a potentiometer it seems like I just used the two wires so maybe this will do the same?

I finally just installed a diode in the loop instead and it's worked like a charm since. Don't ask me how, that's magic, but I was lucky enough to get it from a helpful member that knew that transmissiony/electricalish secret knowledge stuff.

I can check my truck in the daylight to confirm two vs three wires.

 

So checking the Stickies, I didn't have to look at my truck and it is a three wire TPS:

https://www.dieseltruckresource.com/...ce-tps-142641/

Not sure why your doner only has the two wires? I'm getting in way over my head here...

 

Once upon a time I thought about bypassing the TPS. Then I thought about its purpose and fixed it instead.

 

I dont know enough about these trucks but I think your 91 has a cable driven speedometer and the 1991.5 and up have a electric driven speedometer so you need 3 things to make the od work a crank sensor, tps & PMC . or something like a Compushift. ken

 

FWIW, my two '90 non-IC trucks have electronic speedo, and the 89 is mechanical.

 

Agreed.

I tried cleaning mine but to no avail. A new one back then was several hundreds, more than I could afford at the time compared to pennies for a diode and the V6 mode wasn't around yet.

What was your solution?

 

I believe that because your truck was originally a 727 that it did not have the wiring or the computer for that a518

 

Bingo! Vernon nailed it.

I usually delete the TPS right after I delete the A-518 for a Getrag 5 speed, but that is just the way I do it.
The fewer switches, diodes, wires and computers my trucks have the better I like them.

 

I find the same. The '89s are the ones with the speedo cable that runs right into the back of the gauge cluster.

 

But the way I read "I only have the pig tail coming out of the trans with two wires." meant the new trans & pig tail? But if he was talking about his old one, then the donor pigtail should work.

 

I think there's an aftermarket tps substitute on my 93.

 

it only has Over drive. There is no lock up. So the connector/ pig tail only has two wire a power and ground. The later trans would have lock up and that would be the “normal” three wire connector.

 

Agreed! In a later model truck that would have TPS/computer. Where do those wires from the TPS go/do? Straight to the trans to activate the OD and lock up... maybe there is a relay in line. That would be ideal for my retro fit of the TPS delete kit.

If there is a computer in line that runs the show. Then this will be more of a ordeal.

In that case I will go the route of a simple switch to ground to run the OD manually. I’ve seen this in other threads.

 

I believe it does go through the computer so you are probably better off with a switch, some people use the old style dimmer switch on the floor to activate it