O2 Sensors

[Birdman330]

How many O2 Sensors are there Upstream and Downstream. CEL light is on, P0420 Code but no signs of a Cat being bad no loss of power etc... Just a rough idle, engine runs smooth power is good. So I'm going to throw in new O2 sensors since I have a feeling one of them has gone bad.

 

[tjkj2002]

P0420 code is defining that the downstream O2 is following the upstream O2,thus the cats is not doing it's job on bank 1.Does not mean a O2 sensor is bad as that would set a O2 code.


There are 4 O2 sensors on a KJ with the 3.7,2 upstream(1 before each cat) and 2 downstream(1 after each cat),since there is 2 banks.

 

[Fuzzy]

Just a question can u cut the catalytic converters off and run without them. Would it make ur exhaust louder and would it hurt the engine at all

 

[Birdman330]

No, that is a direct violation of Federal Law to remove the Cats and not really possible otherwise; the engine is dependent on the Cats unless it is tuned to run without them via the Computer. I'm sure there are more codes than what the ''Pod'' I hooked up to the Port has read. Just I see every single sign that I do not have a bad Cat but a bad O2 Sensor. My coworker and I talked about it and most likely the Downstream Sensors are shot. Loss of power is usually the first sign a Cat is going bad or starting to plug up, seen it too many times working at my previous shop.

 

[Fuzzy]

Well any ideas on how to make it louder then. I don't wanna get new headers

 

[Birdman330]

Muffler Delete is the only way.

 

[tommudd]

Muffler Delete is the only way.

What Birdman stated on the convertors, don't remove them, will cost ya every which way you turn.
As far as muffler delete, he'd lose a little more power , these motors like some back pressure

to Fuzzy
good muffler and be done , any louder is just annoying in town and on the highway esp. with a 6 cylinder.................... unless its a 235 straight 6 with dual carb's and a split manifold on a 53 Chevrolet with Smithys :emotions33:

 

[gatortail]

quick question fixing to replace all of this.. at the end of the y pipe is that a 3rd cat or a resonator ? before the muffler.

 

[Birdman330]

I haven't had a chance to climb under to do a catalog. So I can't answer that question, Easiest way to tell is if there is an O2 sensor right after it, if there isn't most likely a resonator.

 

[gatortail]

I haven't had a chance to climb under to do a catalog. So I can't answer that question, Easiest way to tell is if there is an O2 sensor right after it, if there isn't most likely a resonator.

ok been told its a cat, been told its a resonator. no sensor in front. figured one of the sharp shooters on could tell me .. thanks..

 

[Snail Farmer]

I believe the 02 models had a third cat but I don't think it was monitored so there wouldn't be o2 sensors.

Sent from my HTC One using the power of Mary's purse

 

[streetglideok]

Not a resonator, it would be the downstream cat, not monitored. It is still required by law to have however. You didn't see resonators till you went to the KK platform.

 

[tjkj2002]

ok been told its a cat, been told its a resonator. no sensor in front. figured one of the sharp shooters on could tell me .. thanks..

It's a non-monitored cat that give the '02 KJ a LEV status.

 

[Birdman330]

I'll have to see what my 07 has.

 

[tjkj2002]

I'll have to see what my 07 has.

Your '07 only has 2 cats in a different locations then a '02 KJ does.

 

[Birdman330]

Which if I understand are on each side drive and passenger, before the y-pipe merges. I hope it is easy to undo my O2 sensors since I believe this is the first actual winter with snow my Jeep has seen. So underneath it is still very clean.

 

[gatortail]

cat

It's a non-monitored cat that give the '02 KJ a LEV status.

Ty. For answer..

 

[Birdman330]

Not only is it the downstream sensor on the passenger side but the cat is partially plugged up. Thursday it gets a new cat and downstream sensor.

 

[vogonpoetry]

My OBD started giving me a P0153 code a few days ago. That corresponds to "Sluggish Response" on Bank 2 Sensor 1, from what I've read. Thats an upstream on the left side. Gas mileage lately has sucked more than usual so i'm thinking I might just replace all of them while I'm at it. Do these normally wear out after 100k? I've read conflicting statements. Some say yes and that you should change them all at some point, but some say only to change them if they fail.

 

[Birdman330]

We think what happened to my KJ is that somebody did a bad fuel induction cleaning, most likely when putting the cleaner in through the intake they revved the engine too high so excess carbon got blown out rather than burned off causing the damage.