ToyWheeler

So I was having problems with my 88 Cherokee laredo and found out I need a new tps. Went to the store and got one. I installed it and now im trying to adjust it. I know the steps you take to do so, but im getting bad readings. My input is only 4.1v and the lowest I can adjust my output to is 5.4v? Why is the output higher than the input? Am I using a wrong meter? It is a multimeter and this ohm setting is the only setting I can get a read on. With the tps off I can manually push the lever on it all the way down to 2.2v, but when it is screwed on to the throttle body the screws only allow it to spin so much and it's not going far enough. I have a manual transmission, but my tps is a automatic transmission tps. Looks exactly the same as my old one I pulled out, and the jeep drove somewhat fine about a week ago. The guy at the part store said at sometime somebody had to switch the tranny out from auto to manual. Am I missing something here, or is this something new to you too? PLEASE HELP ME IM GOING INSANE!

AMCComanche2.5

first thing. get the correct TPS. Usually it would not matter, but anything can happen (Murpy's Law). Next, a TPS at 0% (no throttle) should read ~5v. WOT (100%) should be ~1v. Reply back with your year, make, model, and engine, and I will get you some info on your TPS at school.

AoA

on my 97 my TPS idle was 17-18%

ToyWheeler

So which tps should I get? Do both mount onto the throttle body the same? mine is mounted on the front of it, and ive seen some mounted on the back. O'reileys is ordering me a new one and will be here tomarow. It's the same one I already have in case this one is faulty. It is a 88 Jeep Cherokee Laredo 4.0 straight 6. What exactly does WOT mean? Im new to all of this and this is the first sensor ive messed with. Thank you so much for helping!

danXJ

I just went through this.

thanks to cruiser54 I got it dialed in.

on the 3 wire flat connector back probe the middle wire (B) with negative, put positive on A wire and record voltage, I had 4.82. then you prove the C wire (all letters are embossed on the connector) now C should read 17% of A.

so you go 4.82x.17=8.19 adjust the TPS until you have this percentage.

you will need a multimeter they are cheap from harbor frieght

set it to DC volts... with Key ON but engine not started

ToyWheeler

So I adjust by the flat connector instead of the square one?

danXJ

yes, flat 3 wire is for ENGINE related problems square one is for Tranny problems.

B + A is reference voltage

B + C is out put and should be 17% of it.

mine was 4.83(ref)x.17= .82(output)

ToyWheeler

Alright thank you, im gonna try to fix it tomorrow when it quits raining so hard. I really hope it works. So if I get that dialed in for the motor is the tranny still going to work how it's supposed to? as of right now the tps is completely off, and the new one is still in the box.

danXJ

I would just do engine side, Trans side should even out and only adjust if you have shifting issues.

ToyWheeler

Ok one last question, first you said 4.83x.17=8.19, and now you said 4.83x.17=.82? Is one of them a typo? Im confused which one is it?

ToyWheeler

Alright so I just went out to try and fix it. Got the first reading a+b at 4.86. got excited thinking I was onto something. switched A to C and left neg on b, now im getting a reading of 41mv and it continuously slowly drops.....41.2 41.1 41.0 39.9.... and so on. after 10min of waiting it got down to about 28.something and I took it off, turned it off, and put it back on. It started back over at 41.2mv. none of this is making sence to me!

danXJ

.819 rounded up to .82 is all

ok did you rotate the TPS slightly to get to .826?

if it won't hold steady the TPS might be bad.

Cruiser54 said they can have bad spots in them.

he is mr. renix and his u learned lol

ToyWheeler

Alright one thing after another, I found out how to get it adjusted, went to tighten down the screws and what do you know, they are stripped.... Anybody know where I can order tps screws? Went to the hardware store and tried all different kinds but none of them work.

danXJ

they are 10-24 thread pitch lowes has them. you can buy Allen head screws like I did, I had one break and had to drill and re tap it...

ToyWheeler

So I got the original screw to hold it in place good enough to start it and see, idled for about 5min rpms going up and down and then it died....runs horribly. after it died I plugged the v meter back into it and it was still at .826 so I know it stayed in place. What does this mean? It now runs worst then it did in the first place