Correct way to set up a TPS.

[Dan_69GTX]

My father-in-law will be stopping by later this month. He has a 92 and wants me to reset the TPS that the dealer screwed up.



I don't have a manual for a 92, but do for a 93. Is it the same on the 2 years??



If not anyone know what the idle voltage should be? Any other adjustments needed to help him?



Of course it could be that his trans is ready to puke!.



When he gets here I'll hook up the scanner to his truck and see if I can pull any trouble codes off.



Thanks!



Dan

 

[Paychk]

I checked both my 92 & 93 factory manuals and at idle the TPS should read about 1 volt and wide open should be 2. 25-2. 75 volts above the idle reading.

 

[BushWakr - RIP]

paychk is right on, however,

I've found there is a fair bit of variation in "the correct setting"

If the voltage is too high "at rest" then 3-4, 4-3 will be out of wack. The 3-4 shift will be delayed longer and the jump back down from 4-3 will be a bit touchy too.

If it is too low the thing will shift almost right away.

When my trans. was original I found the best setting to be about . 7 VDC.

I experimented with a range between . 5 and 1. 20 VDC, finally settling on . 7 VDC

At that point it gave me a medium throttle shift into 4th at around 60 Kph (35MPH?)

Also when you check the voltage "at rest" and cycle the throttle to WOT the voltage should increase smoothly with a total increase of about 2. 25 -2. 75 V over the "at rest" voltage.

If, when you slowly open the throttle up (with engine off and Key on) the voltage jumps or twitches then your TPS is either dirty or hooped.

FYI, the center wire on the 3 wire connector of the TPS is the one to use for your "+" signal. You can ground the "-" probe of your meter anywere. I used the "-" on the battery since it was close.

I assume you know there is a shaft out the bottom of the TPS which has 2 "flats" on it for an open end wrench. (7/16" or1/2").

I used a short handled open end and adjusted about . 2VDC at a time and test drive for feel, shift quality, timing. It can be a bit touchy when you adjust it. Once you've moved it a bit, cycle the throttle a couple times and re-check it to make sure its has stayed put.

Hope that helps.



Bob.

 

[Paychk]

As always the voice of direct experience sheds more light than any dozen manuals could possibly hope to. Some times I wish I had a slush box instead of rowing all the time, :{ did any of the 1st Gens come with a lockup converter and overdrive?

 

[BushWakr - RIP]

paychk,



NOPE, and to be honest, I had that choice when I had my upgrade done but chose not to go that route.

SOME of the reasons are obvious. . right...

BTW, I wouldn't exactly call it experience, its more like exercise in testing the limits of sanity (or insanity depending on your perspective )



No rowing for me, slushing all the way. Heck I get to catch some shut eye with all the time and energy is save, what with no extra pedals, and levers to yank.



regards, Bob.

 

[Dan_69GTX]

Thanks Bob and Alan.



When he shows up next week I'll see where it is at. Nope, I didn't know about the 2 flats - never worked on a new diesel that has a TPS - most of my experiance has been on older diesels, gas engines, or the "big boys" diesels. My 96 has the extra workout pedals. (wife doesn't drive it as much then).



Dan

 

[Dan_69GTX]

Figured I'd give a followup here - Thanks for the advice on the change.



I adjusted his truck yesterday. At first his truck too a long time to go from 3-4 - just hung in 3rd too long before shifting. The Voltage was . 71. I changed that to 1. 11 and it seems to work great. He's gonna drive it more today and see if he is happy with it.



Thanks for your help!

Dan

 

[nascar mark]

Originally posted by Dan_69GTX



I adjusted his truck yesterday. At first his truck too a long time to go from 3-4 - just hung in 3rd too long before shifting. The Voltage was . 71. I changed that to 1. 11 and it seems to work great. He's gonna drive it more today and see if he is happy with it.



Dan, This is backwords from were you need to be?

The higher the number, the higher the shift point will be from 3-4.

You need to adjust to a lower number then . 71 and or adjust the throttle valve cable which controls shift speed/ quality and part throttle downshift sensitivity. If too long, shifts will be delayed.



mark

 

[Dan_69GTX]

Hmmm... . thanks for the info.



Guess I'll have to check the length of the throttle valve cable and see where that stands.



It's odd that the change allowed the 3-4 shift to occur (for my likings) correctly. Before the change under light acceleration 1-2,2-3 shifts seemed fine, the 3-4 shift occurred only when you let up on the accelerator. It would stay in 3rd at 40-45 mph unless you let off.



Looks like I can't assume stuff was set up correctly when the last monkey looked at it. I'll have to check all linkages, cables, etc for correct adjustment, pivots for binding, etc.



Oh well - At least if I get everything right it will make my father-in-law happy. Now if I could only get him to allow me to do some mods to his truck. Boy, compared to my truck his is a sled.



Dan

 

[BushWakr - RIP]

I'm certainly no expert on this one but ... . easy does it with the throttle valve cable adjustment. If I remember right that can have some less than pleasant effects if it gets out of hand.

More research needed to be sure but just an FYI.



bob.