Importance of O2 sensor

Predatorxj

Predatorxj

New member
I have recently removed my cat and was wondering what the importance of the downstream O2 sensor is. I know it has something to do with run ability and air/fuel mixture. The sensor has been unplugged for little over 6 months and I haven't noticed any difference in how it runs or performs. Thanks in advance
 
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WJCO

WJCO

Meme King
Predatorxj said:
I have recently removed my cat and was wondering what the importance of the downstream O2 sensor is. I know it has something to do with run ability and air/fuel mixture. The sensor has been unplugged for little over 6 months and I have noticed any difference in how it runs or performs. Thanks in advance
Click to expand...

Well, you've just pissed off a bunch of greenies.

The downstream o2 sensor's main job is to tell how well the cat is working. So right now it no longer has a primary job on your vehicle. Basically the pcm receives inputs from the upstream (pre cat) sensor and compares them with the downstream (post cat) sensor to determine if the cat is doing it's job. The oxygen content that the sensors read also gives the pcm info for your air/fuel mixture. I'm surprised your CEL hasn't turned on. If your gas mileage and driveability is good, then enjoy that lovely Al Gore smoke cloud out the back. If you have emissions testing in your area, it probably won't pass when you go in.
 
J

Jeepnoub

New member
Assuming you meant haven't noticed and not have noticed. Down stream sensors are for monitoring the cat not air/fuel mixture. And depending on how the cars ecu is set up will determine how runs without them hooked up. If not noticing a difference then you are fine.

If your check engine light is on. You can look into o2 sensor emulators
 
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1fastsedan

New member
Post cat sensors are strictly emissions related only. Has zero affect on drivability. Pre cat sensors are the ones that matter as they adjust air fuel ratio. I'm surprised you don't have a CEL.
 
Predatorxj

Predatorxj

New member
The O2 sensor had rubbed against the under body and broke the wires. Cat was welded to muffler and clamped on front pipe. Took cat and old muffler off and put new muffler in its place.
 
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