TPS voltage range questions

**JeepsAndGuns** · 03-10-2015

As some may know, I am planning on swapping out my stock jeep ecm and swapping in a 1227727. I have everything squared away for the swap but I just recently made a discovery.
The jeep TPS sensor uses the same 5 volt reference as the GM system, however the voltage range is different.
I found out when doing some other testing, that the jeep TPS works perfectly fine with the GM system, but when at WOT, it only reads 3.7 volts. It reads the proper .5v at closed throttle. It also reads just fine in the datastream but but when the jeep TB is wot, it is reading only about 85-90%tps on the datastream dash. I tried 3 different jeep tps sensors, all read identical. I'm thinking this may cause some issues? When I hook up a GM sensor, it reads 4.5v at wot. The tps % in the datastream dash reads 100% at 4v, and the voltage keeps going to 4.5 by the time its fully open.

So my next thing my be trying to find a GM (or gm voltage range) tps sensor that might fit the jeep TB. It has two screws aprox 1 5/16 apart and a "blade" of sorts that engages the tps sensor. Anyone maybe know of a GM tps that is close enough I might be able to make work?

Here is a random picture I found online showing what the jeep tps connection looks like.

http://ww2.justanswer.com/uploads/dr...4_152432_3.gif

**sturgillbd** · 03-10-2015

It looks to be the same drive as a later TBI TPS. Could you use a thin piece of aluminum and adapt between the bolt patterns? If so does it turn the same direction? Also look at the tps for a 2000 silverado. May be more easily adapted.

**1project2many** · 03-10-2015

That looks like a fairly common GM TPS mounting. A late 90s 3.1 sensor might work.

Here's a few different ones on one page:
http://www.streetperformance.com/m/c...nc.html?page=2

**JeepsAndGuns** · 03-11-2015

I have a spare one for a vortec TB (96+) and the bolt spacing is way too wide, not to mention the shaft is round with a flat spot instead of a "blade". This is the exact same sensor you both mentioned.
I'm thinking I might just have to look next time I am at the JY and see if I can find anything.
The kinda half round one from the late model TBI's has the correct shaft style, but I would have to get my hands on one to know if I could mod it to work.

**sturgillbd** · 03-11-2015

I have one that I can give you measurements and pictures of if you want. I'll even throw it in the mail for you if you need it. Just let me know.

Brian

**JeepsAndGuns** · 03-11-2015

Sure, take some measurements for me and post them up. The jeep tps screws are roughly 1-5/16 apart.

**1project2many** · 03-11-2015

Is it possible to slot the Jeep sensor so it can be rotated slightly? The minimum voltage needs to be below .75V so you might have just enough room electrically to get the 4V minimum for WOT while keeping the closed throttle voltage in spec. That's what I did with my Toyota TPS for the 7749.

At least one of the sensors in the page I posted is a two screw mount with flat shaft. Application is 98-99 Saturn. Part numbers can be found here:
http://www.yoyopart.com/oem/11987927/bwd-ec3342.html

A thin piece of aluminum could be used to mount the sensor if the bolt holes don't match.

**JeepsAndGuns** · 03-12-2015

That sensor looks a lot like the vortec sensor just with the different shaft connection.

Rotating the sensor might be possible, but the jeep tps has thick steel sleeves for the screws to go through and they are about 5/8in long, so slotting them would be a pain.

If there was a 65mm cable operated GM throttle body that was pretty simple and could be found in the junkyard, I could probably fab a adapter to the jeep intake and be done with it. But I haven't found one yet.

**sturgillbd** · 03-12-2015

Here goes some pics and measurements. Radius from center of TPS to center of mounting holes is approximately .800" (1.6" diameter mounting) Overall length is approx 2.4" Diameter of throttle shaft hole .422" Any other measurement or pic you would like to have, just let me know.
Brian

**JeepsAndGuns** · 03-12-2015

Its still a little wide, but has the right shaft connection. I might pick one up next time I am at the junkyard and see if it could be modded.
I will probably pick up a few different ones and see if I can mod any of them to work.
The shaft only sticks so far out of the jeep TB, so I am limited on how thick of a plate I can use. It would have to be real thin.

**delcowizzid** · 03-12-2015

You can get the sensor above in both clockwise and anticlockwise if your throttle turns the opposite way as well.

**lionelhutz** · 03-12-2015

The Jeep TPS should just be a pot with a wiper that can go across the full resistance like any other TPS. So, I would not be surprised if the problem is that the throttle body shaft does not turn enough degrees of rotation to transition the TPS sensor from 0.5V to 4.5V. If this is the case, adapting a GM sensor will not fix anything.

**JeepsAndGuns** · 03-13-2015

It opens to a full 90 degrees. I just checked with a jeep tps not bolted down, and it will output 4.5v, but its way past WOT. Comparing where it was putting out 4.5v, it was a little over the thickness of one of the screws that hold it on.

Delco, if you look directly at the shaft where the tps mounts, it rotates clockwise.

**1project2many** · 03-13-2015

t opens to a full 90 degrees. I just checked with a jeep tps not bolted down, and it will output 4.5v, but its way past WOT. Comparing where it was putting out 4.5v, it was a little over the thickness of one of the screws that hold it on.

My Toyota sensor is the same way. The sensor allows a sweep greater than 90 degrees and min required voltage to achieve WOT is not the same voltage as the sensor produces at max sweep.

**sturgillbd** · 03-14-2015

JandG, I found a TPS that will probably work. It will take some slotting of holes and maybe washers on the screws. Instead of the connector coming in the side, the connector will stick straight up. You may have to modify your air intake into the throttle body. The one I tested to work came off a 1993 ford escort. The 1990's Ford F250 has the right angle connector but doesn't have as much material to slot the holes. I don't have access to one of those but it probably has the same resistance. The escort mounting holes are about 1/4 of the diameter of the hole wider than the stock jeep. I will post a video of us taking it through the full range of motion using a jeep throttle body and also pics of the sensor etc when I get home in about 1/2 hour.