02 sensor and aftermarket header

[Ramrod310]

I just purchased my first jeep. 1993 Cherokee 4x4.

The previous owner removed the 02 sensor when he installed a new header, it appears there is a plug where the sensor used to be.

I need to get the jeep to pass CA smog. If I screw a new 02 sensor in I should be OK with the aftermarket header or would I need to go back to stock?

also, is there just 1 sensor needed or 2?

thank you

[4.3LXJ]

In ca you need to make sure there is a CARB number on it. If there is, you are OK. There are two O2 sensors. One just in front and one just behind the catalytic converter.

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[Ramrod310]

Right now the jeep no 02 sensors on it. there is a bung for a sensor before the cat but nothing after. Would it be the same sensor before and after the cat?

thanks

[JeepFreak]

My Jeep is a 1994 Cherokee Sport and it has only ONE O2 sensor even though the manual says it 'came' with two. They went off the 1993 model Cherokee which has only ONE O2 sensor. The O2 sensor I have is up near the beginning of the exhaust towards the back of the engine just where the pipes flow from the engine itself. Can't miss it. Just looks like a little connector with a tube sticking out from the side of the exhaust. If needed I can take some pics of mine.

[Ramrod310]

that is great news!
I have the spot for the 02 sensor exactly where you described. It is currently plugged right now with a bolt it looks like. I have a new sensor coming today from amazon, I just need to find where the wires plug into now.

[XJ Wheeler]

I believe the California models had two in those years. If yours doesn't them it probably isn't a Cali model and came from elsewhere.

Sent via messenger pigeon - i talk, he types.

[JeepFreak]

that is great news!
I have the spot for the 02 sensor exactly where you described. It is currently plugged right now with a bolt it looks like. I have a new sensor coming today from amazon, I just need to find where the wires plug into now.

Just as an FYI, sometimes the O2 sensor can be hard to remove from the exhaust if the vehicle is below 120*F. Don't force it to rotate out of the exhaust if it's hard to move. Just start the engine and let it get to operating temperature (usually 15 minutes @ idling) then shut it off and try again. A WARNING WHEN REMOVING: there is a pigtail attached permanently to the sensor!!! Do not clean the sensor or the pigtail with ANY solvent EVER! Your new one will come with a pigtail connection that should connect to the existing wires. When you remove the old sensor and put in a new one, DO NOT TOUCH the sensor with BARE hands. Wear gloves. ANY AND ALL contaminants that get on the sensor could damage it permanently. This includes the oil on your hands. Most new sensors will be precoated with dielectric grease. Make sure you put dielectric grease on anyway BUT be absolutely sure that it is the correct type otherwise you could electrically insulate the sensor and make it useless.

[Ramrod310]

ok I got a new sensor but there is no where to plug it into!? I'm thinking the previous owner cut the connector off? A lot of the wires appears to be tampered with on this jeep, engine compartment and under the dash.

[JeepFreak]

ok I got a new sensor but there is no where to plug it into!? I'm thinking the previous owner cut the connector off? A lot of the wires appears to be tampered with on this jeep, engine compartment and under the dash.

Take some pics and post them. I will see what I can do and then post pics of my Jeep since they are literally sister years. You'll be able to see what it's supposed to look like.

[Ramrod310]

I was able to get the sensor hooked up. The plug was tucked away and out of sight but I found it and everything seems to be good, the check engine light doesn't come on anymore.

I was able to clean up the wires and look over them closely to kind of figure out what was going on. The only problem that I have left electrical wise is that the lights on the left that indicate 2WD 4H 4L etc doesn't work.

[JeepFreak]

I was able to get the sensor hooked up. The plug was tucked away and out of sight but I found it and everything seems to be good, the check engine light doesn't come on anymore.

I was able to clean up the wires and look over them closely to kind of figure out what was going on. The only problem that I have left electrical wise is that the lights on the left that indicate 2WD 4H 4L etc doesn't work.

Check that the bulbs aren't burned out or that the wires and connectors to the back of the dash aren't fried. For me, it usually ends up burning out a bulb more than burning out a wire. I would start there and most of them are simple tug-n-pull bulbs that pop right out without twisting but some of them have little 'ears' on the side that lock it in place so make sure you know which is which before you just pull on them.

It isn't hard to remove the dash either. Plenty of Jeepers on YT have posted videos explaining how to remove it.