Do your adjustments using the 3-port weatherpac connector. That's the one the Renix ECM uses. The 4-port is for the transmission computer, assuming you have an automatic. If it's a manual, then nothing will be connected to the 4-port.
Additionally, while you may get it set correctly, these TPSs are a variable potentiometers. These also commonly develop dead spots. The best way I've found to determine if a sensor is good or bad is to use an analog multimeter, or volt-ohm-meter. Measuring the resistance of both sides of the variable lead, the meter's needle should move smoothly and proportionately relative to the sensor movement's range of motion. It should go up and down, or down and up depending on which end port you are measuring from, very smoothly, with no sporadic movement in the meter's needle.
It depends on what your issue is--the 3-wire connector for ECU/engine management or the 4-wire connector for TCU/transmission management.
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. Wire "A" is positive. Wire
"B" is ground. Remove the three-wire connector from the TPS. Key ON, measure voltage from "A" positive to
"B" ground. Note the voltage reading--this is your REFERENCE voltage. Now, reconnect the three-wire connector to the TPS. Key ON, back-probe the connector at wires
"C" positive and
"B" ground. Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. 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 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 four-wire connector. For the automatic transmission equipped vehicles the four-wire connector provides data to the TCU. Disconnect the four-wire connector. Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your REFERENCE voltage. Now, reconnect the four-wire connector to the TPS. 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. 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.
