If I don't put a catalytic convertor back in, will it set off a CEL?

[Bargain Box]

I have read a lot on here but I have not found the answer to my questions on this. I have a 99 with only 1 cat and 2 oxygen sensors. One sensor before the cat and one after. The sensor before the cat is for A/F and the one after the cat is for detecting if the cat is working. Someone correct me if I missed something so far. The PO cut the cat pipe really short and didn't leave me a lot of meat so it's hard to keep the tail section on with out leaks. The cat is also in bad shape. Where I'm at my emission test is visual only. The question is, if I don't put a cat back in, will this set off a CEL and if so does it matter and can it be turned off/tricked so I don't have to buy another cat. I want to redo the cat pipe and I already have a new muffler and tailpipe. Just trying to see what I'm budgeting for. Thanks in advance.

 

[TheBoogieman]

It won't pass "visual" emissions without the cat either. Buy a universal cat for $100 and weld everything on to avoid leaks.

 

[BLindzy]

I have a "test pipe" in place of my CAT on my 97. I have not gotten a CEL light in 5 years like this. We have not tests here in IN so I'm good, however you will not pass the visual if you remove it.

 

[Bargain Box]

It won't pass "visual" emissions without the cat either. Buy a universal cat for $100 and weld everything on to avoid leaks.

I was going to use a test pipe as they are significantly less than a cat. At this point I don't see the need for having one since it's almost 25 years old. I'm a few years from likely not needing visual either.

 

[Chris]

Yes, it will set off a CEL. That CEL can be gotten rid of with HPTuners software.

 

[Irun]

Just do what @TheBoogieman said. Weld in a universal Cat, with an O2 bung, and call it a day. This is a much cheaper option and will suffice for your visual. I can't remember if the '99 has a 2.5" pipe, but here's an example.

https://www.amazon.com/dp/B09BD6CLWR/?tag=wranglerorg-20

 

[Bargain Box]

Yes, it will set off a CEL. That CEL can be gotten rid of with HPTuners software.

I greatly value your response. I've seen you state this before. The reason I asked again is I've found a lot of people like @BLindzy state they did not get a CEL. I've never owned a vehicle that did not get a CEL with an after cat O2 sensor.

 

[Chris]

I greatly value your response. I've seen you state this before. The reason I asked again is I've found a lot of people like @BLindzy state they did not get a CEL. I've never owned a vehicle that did not get a CEL with an eftwr cat O2 sensor.

You may get lucky but I'd think of anything what is most likely to happen is you remove the cat, drive around for a while, and then the CEL comes on at some point. When I removed my cats the light came on about 10 minutes into driving it.

Again, you may get lucky. The post cat O2 sensor will detect there isn't a cat and throw the code. With HPTuners you can disable the post cat O2 sensor completely, thus eliminating any possibility for a code.

Now granted this isn't legal, you can still do it for "off-road only" purposes.

 

[Bargain Box]

Just do what @TheBoogieman said. Weld in a universal Cat, with an O2 bung, and call it a day. This is a much cheaper option and will suffice for your visual. I can't remember if the '99 has a 2.5" pipe, but here's an example.

https://www.amazon.com/dp/B09BD6CLWR/?tag=wranglerorg-20

I do not possess the skills or tools to do this. Muffler shops around here want an arm and a leg to do the work.

 

[Bargain Box]

You may get lucky but I'd think of anything what is most likely to happen is you remove the cat, drive around for a while, and then the CEL comes on at some point. When I removed my cats the light came on about 10 minutes into driving it.

Again, you may get lucky. The post cat O2 sensor will detect there isn't a cat and throw the code. With HPTuners you can disable the post cat O2 sensor completely, thus eliminating any possibility for a code.

Now granted this isn't legal, you can still do it for "off-road only" purposes.

I wish I knew someone with the software.

 

[Chris]

I wish I knew someone with the software.

You can buy it and do it yourself, it's not that hard. But if you know someone with the software it will only cost you about $99 for the credits to tune your VIN versus about $400 if you buy the software and tune it yourself.

 

[BLindzy]

Yes, it will set off a CEL. That CEL can be gotten rid of with HPTuners software.

Guess I have been lucky. I have had CEL lights before, but never for this.

 

[Irun]

I do not possess the skills or tools to do this. Muffler shops around here want an arm and a leg to do the work.

Then don't weld it. Cut the pipe and use band clamps. Something like this.
https://www.amazon.com/dp/B001AX9UD4/?tag=wranglerorg-20
You just need to determine how much to cut and what size convertor and clamps you need. Basic tools will do this job.

 

[Chris]

Guess I have been lucky. I have had CEL lights before, but never for this.

Hey now...go knock on wood

 

[Bargain Box]

Thanks for the help everyone. I'll weigh my options. The good news is I don't have to rush. For now, I have a half a** holding itself together slightly leaky exhaust.