Dwinthrup

Can I use one on a 1990 Cherokee? Or is it required to be heated?

Abovetimberline

Yes you can use a non heated 02 sensor on a 90,the heated sensor is only to get it to closed loop quicker and keep it in closed loop for long periods at idle.

Dwinthrup

Do you know what wire to hook it up to?

Abovetimberline

It is actually 2 wires and it hooks up to a connector,if you only have one wire you are missing something.

Dwinthrup

Looks like this I think it grounds with the engine

Dwinthrup

Found this in the tech section under renix sensors

Oxygen Sensor

Located in the exhaust manifold. To test, using an ohmmeter, disconnect the O2 sensor connector. Connect the ohmmeter test leads to connector terminals A and B of the sensor connector. Resistance should be between 5 and 7 ohms. Replace the sensor is the ohmmeter displays and infinite reading. I don't know about you, but this test is pretty vague. They say it should be between 5 and 7 ohms, but infinite is bad. What if you get a reading of 13 ohms or 100 for that matter? I wasn't too fond of this test as I found it is a test of the O2 sensor heating element!. One other thing you can do with the O2 sensor is hook up the voltmeter to terminals B and C (I can't remember if those are the right letters, but you want to get the sensor wire (believe it was blue) and the ground wire, or just ground to something else) with the connector hooked up and the engine on, warm, and idling. You should notice the voltage jumping up and down in about 2 second or less intervals. If it doesn't jump up and down considerably or takes longer than 2 seconds to do so, change it.

> What does it do? The ECU interprets the voltage from this sensor which analyzes the oxygen content on the exhaust gas and varies the air-fuel ratio accordingly.

So by the looks of this I put it on the blue wire?

Also I belive that the ecm only uses ithe sensors in open loop once it's warm, however I could be wrong.

Abovetimberline

Mine is a 3 wire heated and I just tried to look up the sensor you are showing and cannot find it,it is an older style and to my knowledge will not even hook up to the connector on your jeep,your connector should be flat and have 3 wires.

Dwinthrup

That's not the actual one I have mine is a bosch o 258 001 027, that one was one I found upon googleing a one wire 02 to try and find you a pic of what I was asking about.

Abovetimberline

when you look at yours how many wires does it have?

Dwinthrup

Looks like this

Abovetimberline

That is a 3 wire heated,2 for actual reading and one is a 12 volt heater wire that heats up the sensor to 600 degrees and keeps it there,the older 2 wire depended on exhaust to keep them heated to 600 degrees and when idling or intial startup they would run rich until the 02 sensor got hot enough to work,the sensor will not produce a voltage until it is at 600 degrees,then it will produce about .05 volts and start to provide info to the pcm,it will adjust injector on time as needed depending on weather your jeep is running rich or lean. it is not as big of an issue on yours as it would be on an 96 or later where you have at least 2 02 sensors,one before the cat and one after,later models had as many as 4 depending on weather they had pre cats or warm-up cats.
Hope that helps