There is no Limp Mode on a Renix.

Where did you buy that TPS?

Bosch O2 sensor? I don't like them.

Have you cleaned/refreshed your relay connections? Swapped relays all down one position?

For the Renix years, 87-90, the O2 sensor has 3 wires, 2 black and 1 orange. The orange wire (largest gauge of the 3) is the 12-14 volt power that comes from the O2 sensor heater relay on the passenger side firewall, and that powers the internal heater in the sensor so that the sensor can work at idle, and almost immediately after start up. Loss of that power will hurt gas mileage even with a good O2 sensor.

One of the black wires is a common ground for the heater power and O2 signal to the ECU, so a poor ground will give a voltage feedback from the heater power input, to the ECU causing poor mileage even with a good O2 sensor.

The third wire, also black is a voltage feed wire, 5 volts, from the ECU to the O2 sensor. The O2 sensor is an O2 concentration sensitive variable resistor. At optimal O2 concentration the 5 volt input feed to the O2 sensor drops to 2.45 volts due to losses across the O2 sensor to ground. That same wire if disconnected from the O2 sensor will read 5 volts constant to ground.

At idle that voltage should read 1-4 volts oscillating quickly back and forth roughly once every second. At 2000 rpm it should run between 2 and 3 volts max, and is optimally running between 2.3 and 2.6 volts at 2000 rpm (in park). A digital meter can NOT be used for reading the O2 sensor voltage, but it can be used to test the ground and the 12-14 volts to the heater and the 5 volt feed from the ECU with power on and engine off. You must use an old style analog meter with the needle gauge on the display to see the voltage swing back and forth with the engine runing.

If the O2 sensor readings are not right, say they read 4 volts or 1 volt steady, you have a problem. BUT before you blame the O2 sensor make sure it has good wiring, and make sure the proper voltage is feeding it, by turning power on, engine off to read the engine off voltage feeds (12-14 volts on the orange wire, and 5 volts on one of the two black wires), and ensure the ground wire (power off) reads less than 1 ohm to the battery negative post.

A leaky exhaust system or leaky fuel injector(s), or bad compression, bad rings or leaky valves, bad plugs, wires, cap, rotor, HV coil, and so on, or combination of these, can also cause a lean or rich condition that gives you high or low O2 sensor readings that are not the O2 sensors fault, so try and verify those other items also before buying parts like an O2 sensor to fix your problem.

 

Tps was bought from Lordco

Yes Bosch is all I could get

Yes I have cleaned and refreshed the relays

I'll look into my voltage going to my O2, but I do not have a analog meter to test the actual sensor tho

 

Today I checked my voltage to the O2 sensor, 14volt, 5volt and 0.1 ohms restance to ground.

I also decided to check my restance to ground on my sensor circuit, when the engine is off key on I have .3-.1 ohms depending on location where I am probing but when it's running my restance is 5.8-6.4?!? Is this normal?

I been doing some reading and from my understanding when I unplug my cts and mat sensors my idle increases because the computer thinks the motor is cold and adding more fuel, is this correct? unplugging these sensors seems to be the only solution to increasing my idle

Also I have located a tool to read the computer and see if it will enlighten me on any info, any ideas what I should be looking for?

Thanks

 

Yes. The resistance will measure high with it running.

What tool?

 

It's a snap on

 

MT2500 Brick I bet.

I can tell you what to look for. Monitor the sensors, especially the O2.

Post up any results.

 

Okay here are my results

Snap on modis

Rpm, 550-628
O2, 0.5 - 4.8 volts ( keeps changing)
Inj ms, 4.2 - 4.6
Loop, open for a few sec after start up then go into closed
Exhaust, bounces from lean to rich
St fuel, 1 - 14
Lt fuel, 128
Map, 1.7 - 1.8
Map, 45kpa
Main vac, 50
Baro kpa, 95
Tps, 86
Throttle, 17%
Throttle sw, closed
Coolant, 93*c
Intake temp, 55*c (this seems off)
Spark advance BTDC, 14-15*
Knock, 0

 

Now get the readings at 2500 RPM for me.

 

After seeing my results I think everything looks ok to me rpm seems decent, I was actually able to see what it was and not just going of my rpm gauge.

I also pulled the plugs again tonight to see what they looked like, cus I have actually been driving it around now. And they were a perfect light brown color

I am trusting that my new Bosch O2 sensor is doing its job

My main concern is this almost stall issue when letting off throttle and near stalling issue
Maybe a faulty or failing tps? Failing cps?

 

Yeah I forgot to do that part today, I'll do it tomorrow and post the results

 

Snap on modis

Rpm, 2450
O2, 0.45- 4.16volts ( keeps changing but less variance)
Inj ms, 3.7
Loop, open for a few sec after start up then go into closed
Exhaust, bounces from lean to rich
St fuel, 22-45
Lt fuel, 126
Map, .9
Map, 27kpa
Main vac, 69
Baro kpa, 96
Tps, 1.09
Throttle, 22%
Throttle sw, partial
Coolant, 101
Intake temp, 49c (this seems off)
Spark advance BTDC, 31-32*
Knock, 6-9

 

Move the tester out of mumblemeters mode.

Throttle should be closed, not partial, and about 16%. closed being the most important.

Get that in order and run it again in the proper mode.

O2 sensor is working well. Spark advance and knock readings are fine also.

 

I will not be able to get my hands on tester for two weeks again, but this time I brought the jeep and a big tool box with me

 

One thing I have noticed, I am getting better millage since I put in the new o2 sensor.

i will attach a couple links with some clips i made today of my vacuum at idol and revved up, let me know what you think

 

Your manifold vacuum seems a little low. Perhaps the gauge is faulty? When you get the Brick hooked up again, let's see what it says the vacuum is at.

Have you indexed your distributor?