cruiser54

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: With the Key OFF, and 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. Wiggle the wiring harness where it parallels the valve cover and also over near the MAP sensor on the firewall. If you see more than 1 ohm of resistance, or fluctuation in your ohms reading, 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 only a flat three-wire TPS mounted on the throttle body and it provides data input to the ECU. It 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. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you
have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.

Sometimes, after adjusting your TPS the way outlined above, you may experience a high idle upon starting. If that happens, shut the engine off and reconnect your probes to B and C. Start the engine and while watching your meter, turn the TPS clockwise until the idle drops to normal and then rotate it back counterclockwise to your desired output voltage.

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, as outlined above—FOR ALL 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. THIS SQUARE FOUR WIRE CONNECTOR IS USED FOR TRANSMISSION/SHIFTING RELATED ISSUES ONLY. 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.
FOR AUTOMATIC TRANSMISSION RELATED ISSUES: Check the square four-wire connector side of the TPS.
If you have ENGINE ISSUES check the flat 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 09-22-2012

swayd

So this might sound dumb but I could not for the life of me get a reading on any of the wires except "B" on the flat connector. I back probed them and all at least 3 times each and the ignition switch was in the on position but I was getting no readings. What am I doing wrong or is my sensor fried?

Jakers

You'll have to wiggle it a bit. Took me like 5 minutes to finally get a reading on mine but you will get a reading.

swayd

Wiggle in the paper clips? Ok in gunna try again tomorrow morning.

PDEM87

Was your meter set to DC voltage or was it set to ohms? If your set on DC voltage then A and C should be detectable and not B (back probing with the key on, of course). If you are set on ohms then only B will read if the other lead is grounded.

swayd

Yes I was set to ohms. Thanks for the tip.

PDEM87

Learning new things is both frustrating and rewarding, isn't it? I figure knowledge is never a waste of time.

cruiser54

He'll have this figured out in no time.

This could help some day:



http://www.ladyada.net/learn/multimeter/

swayd

Ok so it's not the TPS. I went ahead and disconnected the vacuum hose that I originally found disconnected. I put my finger right on the hole and that is where a lot of air was going IN. So I checked the air filter is black and does not look like a jeep filter because it was just folded in there somehow. Doesn't look like a jeep part. Off to go buy a new filter!

cruiser54

Progress. Seen this?

swayd

Yesi hope.
I haven't and honestly it's i don't understand it.

cruiser54

Print it out. Take a deep breath. Verify that all your vacuum hoses are attached to the correct places.

swayd

Done. All plugged in and in the correct places. Also replaced the air filter and it's still jerking on me. Now I'm going to go out on a limb and say it's the map sensor. Could that be the culprit. Is there a way I can test it?

cruiser54

When and where is it "jerking"?

swayd

While in drive. It will do it at low speeds and high speeds but only when I have my foot on the gas pedal. Sometimes it will jerk and die out and sometimes at a full stop it feels like it's drowning out about to die. BUT, with that one vacuum line disconnected to the throttle body that connects to the MAP it runs like a champ just guzzles gas and smells horribly like exhaust fumes.
It does not jerk while shifting, thank god.