TPS will not adjust to correct voltage

[Joseph V]

I I went thru the steps to adjust the TPS on my 88 Comanche Chief 4.0.  My input voltage is not 5.0 volts, it is only 4.33.   So using the ratio, the output should 0.736 volts.  My TPS will only adjust to 0.54volts.  I bought two different ones, one from O’Reilly and another from Advance Auto Parts. Both only adjusted to 0.17 volts.  I put the original back in.

The question is:  is the low input causing the TPS to not be able to adjust or if the input voltage really doesn’t matter as long as the ratio is correct, then can anyone recommend a new TPS that will work?

 

 

[Ωhm]

Check and make sure the TPS wiper arm, is on the correct side of the throttle plate wiper. Sound like it's on the wrong side (0.17vdc).

[Joseph V]

It’s definitely on the correct side.

 

[cruiser54]

Have you completed Tips 1 and 3 on my website? 

 

are you using Tip 8 as a guideline for your TPS adjustment? 

[Joseph V]

Yes, I cleaned all grounds and pulled ever connection I could find.  I am using the information in your Tip number 8 to adjust the TPS.

I’m just trying to understand why the original throttle position sensor can be adjusted from 0 to .55 but no further. And why the new ones will only go from 0 to .17

Also the low input voltage must indicate something?

[cruiser54]

Perhaps your original TPS is bad and the replacements are also?

 

How does it run at 54%?

[Joseph V]

I don’t understand what you mean by 54%, 

At 4.33 volts input voltage x 17%= .7361 volts. This is the reading I should be getting.  
I am only able to get 0.54 volts output. 
.54/.7361 = 73.61% of where it should be.
 

 

[Joseph V]

If you mean .54 volts, the truck runs pretty good except that when you first start it , it dies.  Restart and it runs good.  Sometimes when I let up on the gas, it will die.  

[cruiser54]

Wanna try something? Is your throttle body clean? 

Open up the throttle plates a skosh and remember how far you turned the screw. Try 1/4 turn for fun. See what TPS reads and then drive it. 

[Joseph V]

If you mean .54 volts, the truck runs pretty good except that when you first start it , it dies.  Restart and it runs good.  Sometimes when I let up on the gas, it will die.  

[Joseph V]

Ok, I’ll give it a try and let you know.  Thumbs crossed.  
( did clean the throttle body, but I used some carburetor cleaner I had. I hope I didn’t mess it up.)

[cruiser54]

You can't hurt the throttle body itself with carb cleaner.