Get the TB butterfly screw set right before doing the TPS.

RENIX TPS ADJUSTMENT
Before attempting to adjust your TPS be sure the throttle body has been recently cleaned.
It's especially important that the edges of the throttle butterfly are free of any carbon build-up.
IMPORTANT NOTE: Using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector
of the TPS . The letters are embossed on the connector itself.
Touch the black lead of your meter to the negative battery post.
If you see more than 1 ohm of resistance some modifications to the sensor ground harness will be
necessary. The harness repair must be performed before proceeding.
I can provide an instruction sheet for that if needed.
MANUAL TRANSMISSION:
RENIX manual transmission equipped XJs have a three-wire TPS mounted on the throttle body.
This manual transmission vehicle TPS provides data input to the ECU. The manual transmission
TPS has three wires in the connector and they're clearly embossed with the letters A,B, and C.
Wire "A" is positive.
Wire "B" is ground.
Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors..
Note the voltage reading--this is your REFERENCE voltage.
Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your
OUTPUT voltage.
Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For
example: 4.82 volts X .17=.82 volts. Adjust the TPS until you have achieved this percentage. If
you can't achieve the correct output voltage replace the TPS and start over.
AUTOMATIC TRANSMISSION:
RENIX automatic transmission equipped XJs have a TPS with two connectors. There is a flat three-
wire connector, same as the manual transmission vehicles have, and it is tested the same as the
manual transmission equipped vehicles--FOR ENGINE MANAGEMENT RELATED ISSUES.
However, the automatic TPS also has a square four-wire connector clearly embossed with the letters
A,B,C, and D. It only uses three wires and provides information to the Transmission Control Module.
Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your
REFERENCE voltage.
Back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT
voltage. Your OUTPUT voltage needs to be eighty-three percent of your REFERENCE voltage.
For example 4.8 volts X .83=3.98 volts. Adjust the TPS until you have achieved this percentage.
If you can't, replace the TPS and start over.
So, if you have an automatic equipped XJ your TPS has two sides--one side feeds the ECU, and
the other side feeds the TCU. If you have TRANSMISSION issues check the four-wire
connector side of the TPS. If you have ENGINE issues check the three-wire connector side of
the TPS.
For those with a MANUAL TRANSMISSION--the TPS for the manual transmission XJs is
stupid expensive. You can substitute the automatic transmission TPS which is reasonably priced.
Revised 11-28-2011

 

I've gone through my set of metric allen wrenches and can't get the screw to turn with any of them...what size is it supposed to be? I feel like the 3.5 was closest...

 

Try some American ones then. Somebody probably futzed it up. You might need to remove it to get this done. If you do, get a new gasket.

 

Listen to Cruiser54 man. Him and a few others helped me tackle my 89. I messed with so many sensors, bought new sensors, did ground freshening *which you should do if you never have* the whole nine yards. This was how my jeep was idling before.

http://youtu.be/N25MF18G2BU


My whole issue was the TB butterfly screw. The previous owners messed with it *and messed it up* to put a band-aid on a simple issue to fix. All of my sensors minus the stator and knock are brand new now. Once I bent the throttle tab back, I got instant gratification on a lower idle. Today, I fine tuned it *since I'd still hit 1000 when hot, and only 700 when cold* and I know have the hot idle down to 700!

http://youtu.be/s3c_jbsHB2s

Good luck man, and keep us posted!

 

Yep I posted in my other thread about idle that I got it fixed! 15 minutes ago! Feeeeeeels good. It sucked holding the brake really hard because I was idling at 1200...ha

 

Ground refreshing, C101 cleaning, coil to ICU contact cleaning, connector refreshing, sensor ground testing etc are super important on these old Renix Jeeps. And the beauty of it all is that it only requires a little bit of time, almost no parts, and the results are a more dependable Jeep. And, the write-ups are free!! Enjoy your Renix!!!