CEL after defouler install

[boostedeco]

so i just put a cvfab catted downpipe on my car and installed a defouler to help with my CEL, and it didn't come off, my mechanics says i need to get a new sensor and that the defouler is fine, how do i know it's not just the defouler placement or not???

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[FreePenguin]

What defouler do you have
Some styles are better than others

 

[boostedeco]

What defouler do you have
Some styles are better than others

im not sure the exact brand, my buddy had it on his and it worked perfectly fine, just my mechanic says he swears it has to be the sensor itsself but if i buy one and it stays on then i'm just out money, is there a code that lets you know sensor is bad or if it's just the defouler not working will it be the same code when scanned anyways

 

[FreePenguin]

Nope because defouler doesn’t have a code it simply pulls it further from stream to help defouler.

I had good luck with the vibrant o2 defouler in vehicles some like 90* turns

I hear bad things about them w the o2 sensors on end too

 

[boostedeco]

Nope because defouler doesn’t have a code it simply pulls it further from stream to help defouler.

I had good luck with the vibrant o2 defouler in vehicles some like 90* turns

I hear bad things about them w the o2 sensors on end too

you know if there would be any signs that it's the sensor and not the defouler, would my car smell weird or run super rough, i know they recommend changing o2 sensor every 60-90k miles and i have 72k, who knows i guess i won't know until i put a new sensor if that was it or not

 

[FreePenguin]

The rear o2 doesn’t change your cars performance

It just does this

Your exhaust stinks o2 light on
Your exhaust is cleannn o2 light off

Someone correct me, but I believe upper o2 is the only one that matters

Now if you see a lot of black soot where tip of exhaust is, black soot. You’re running rich. I only speak bc happened on one of my tunes was too rich from changing dish pipes out on ecoboost so my ecu was dumping fuel to compensate

Car drive fine, but saw a ton of black soot over few thousand miles on bumper valence, came off easy with degreaser 9 though

 

[boostedeco]

The rear o2 doesn’t change your cars performance

It just does this

Your exhaust stinks o2 light on
Your exhaust is cleannn o2 light off

Someone correct me, but I believe upper o2 is the only one that matters

Now if you see a lot of black soot where tip of exhaust is, black soot. You’re running rich. I only speak bc happened on one of my tunes was too rich from changing dish pipes out on ecoboost so my ecu was dumping fuel to compensate

Car drive fine, but saw a ton of black soot over few thousand miles on bumper valence, came off easy with degreaser 9 though

now that you say that i do have black soot on my exhaust tips!!!

 

[WildHorse]

Rear o2 monitors cat efficiency. That's it. So you'll likely see a p0420 or p0430 which doesn't affect anything. If that's the cel your seeing move the o2 further out of the exhaust stream.

 

[FreePenguin]

now that you say that i do have black soot on my exhaust tips!!!

youre always going to have black soot on exhaust tips. its exhaust.
im talking I started getting black residue on the bumper, around it. lemme show ya.

the brown on pic, my bumper was getting sooted up in this area, a heavy dirty coat. degreaser Nine removed it all, easy. but yeah, once I went back to stock downpipes and tune was proper, zero residue ever came back. once I had a device to check trims, I was dumping like 20% more fuel or whatever to compensate for extra flow was all out of whack, it was fixed though.

 

[NASteve]

Was the CEL on before the install or not? If not then it may not be the sensor, if it was then clear the code and see if it comes back.

 

[melwff]

Post the actual code

 

[Genxer]

If you replaced the cat then hopefully it is performing in spec, or it can throw a code as well. With an aftermarket part you never know. Make sure you got everything plugged back in after the install. Also, you may need to drive a couple of cycles to reset the CEL.

 

[boostedeco]

Was the CEL on before the install or not? If not then it may not be the sensor, if it was then clear the code and see if it comes back.

just tried this about to go drive and see if she comes back on

 

[boostedeco]

Post the actual code

it was P0054 and P0141

 

[melwff]

it was P0054 and P0141

You have 72k on the sensor, change it.
https://www.obd-codes.com/p0054
https://www.obd-codes.com/p0141

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