Can you delete one catalytic converter without throwing codes?

[beingnotdoing]

TL;DR: can I replace my second catalytic converter with a straight pipe that has a built in O2 sensor flange and not throw any codes?

I've got a 2002 and every year I have to crawl under my rig to fix my annual exhaust leak for the Virginia safety inspection. If you've got an exhaust leak, you fail. I got tired of carbon steel replacements, constant welds, and muffler goop this year and bought a stainless cat-back kit from MagnaFlow. It came with an extra pipe (complete with O2 flange) for the earlier (1996-2000?) year 3rd gens which only had one cat.

However, I still have exhaust leaks coming from my catalytic converters and I'm going to replace both of them. I am committed to using stainless steel to combat the rust issue, so I'm looking at the MagnaFlow catalytic converters. Each one costs over $700 as of writing on 8/2022.

Since I've got a pipe on hand that could act as a replacement for one cat, I was thinking about just ordering cat #1 and saving myself $700. Has anyone had any experience trying to delete one catalytic converter from their 3rd gen 4Runner?

I do live in an area with no emissions testing, but I was thinking it would still pass even if I didn't since it would still have one catalytic converter.

Wisdom, experience, ideas, or ridicule are all welcome. Unless you live in California. Then I don't want to hear from the likes of you and your non-rusty rigs. :crybaby:

 

[Bad Luck]

TL;DR: can I replace my second catalytic converter with a straight pipe that has a built in O2 sensor flange and not throw any codes?

I've got a 2002 and every year I have to crawl under my rig to fix my annual exhaust leak for the Virginia safety inspection. If you've got an exhaust leak, you fail. I got tired of carbon steel replacements, constant welds, and muffler goop this year and bought a stainless cat-back kit from MagnaFlow. It came with an extra pipe (complete with O2 flange) for the earlier (1996-2000?) year 3rd gens which only had one cat.

However, I still have exhaust leaks coming from my catalytic converters and I'm going to replace both of them. I am committed to using stainless steel to combat the rust issue, so I'm looking at the MagnaFlow catalytic converters. Each one costs over $700 as of writing on 8/2022.

Since I've got a pipe on hand that could act as a replacement for one cat, I was thinking about just ordering cat #1 and saving myself $700. Has anyone had any experience trying to delete one catalytic converter from their 3rd gen 4Runner?

I do live in an area with no emissions testing, but I was thinking it would still pass even if I didn't since it would still have one catalytic converter.

Wisdom, experience, ideas, or ridicule are all welcome. Unless you live in California. Then I don't want to hear from the likes of you and your non-rusty rigs. :crybaby:

If you are trying to use a bolt in catalytic converter for a 2000 and older Federal emissions vehicle it won't bolt up to the exhaust manifolds. Federal and California emissions have different exhaust manifold bolt flange patterns for the catalytic converter(s) to bolt to. In 2001 all 4Runners have the same exhaust as 2000 and older California emissions (which is what you have).

 

[phattyduck]

Wisdom, experience, ideas, or ridicule are all welcome. Unless you live in California. Then I don't want to hear from the likes of you and your non-rusty rigs. :crybaby:

Move to California. Plenty of room now that a bunch of people are leaving. :doh:

To answer your main question though, the second cat has not sensors after it and can be replaced with a straight pipe without causing ECU issues. The only issue is possible visual inspections and maybe slightly higher tailpipe emissions.

-Charlie

 

[brillo_76]

If Virginia is similar to PA county's that don't have emmision testing, I would think you be fine as you still have a cat on your exhaust.

However, it maybe more up to the inspector and state laws. I unfortunately, don't know the VA laws..

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[TheDurk]

Move to California. Plenty of room now that a bunch of people are leaving. :doh:

To answer your main question though, the second cat has not sensors after it and can be replaced with a straight pipe without causing ECU issues. The only issue is possible visual inspections and maybe slightly higher tailpipe emissions.

-Charlie

Charlie, for the first time in our many years on this board together, I have to disagree with you. The downstream sensor port on a Cali. like my '99, is on the muffler intake pipe, after the second cat. I have no direct experience in a delete, but the Cali. spec is very aggressive and I doubt the ECM would be happy with a cat delete. It's hard enough to keep that light off with two.

See the port in the image below of a Cali. muffler...

 

[96RedRunner]

My 01 50 state fed emissions has O2 sensor after 2nd Cat on muffler section 02's the same. [MENTION=10169]TheDurk[/MENTION] well said.

 

[Babyfood1217]

Can confirm, after dealing with having to replace my exhaust this week, that 2002 non-CARB emission 4Runner‘s, have the second O2 sensor on the mid pipe that plays host to the 2nd catalytic converter. CARB versions have their second O2 sensor on the muffler section.


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[Twisted Sid]

Might be able to get away with a O2 sensor spacer or the O2 simulator

 

[phattyduck]

Charlie, for the first time in our many years on this board together, I have to disagree with you.

I'd call it a correction, not a disagreement. I went back and checked my pictures (not near the 4Runner itself) and you are right. I'm used to so many other vehicles I've worked on where that is the case!

I can get mine to throw a P0420 code these days, but only if I'm in very slow traffic for 10+ minutes - moving, but never stopping. Still blows clean out the tailpipe for actual emissions tests, at least. Just does it if the traffic on my commute is just right (errrr... wrong?).

-Charlie

 

[19963.4lsr5]

I'd call it a correction, not a disagreement. I went back and checked my pictures (not near the 4Runner itself) and you are right. I'm used to so many other vehicles I've worked on where that is the case!

I can get mine to throw a P0420 code these days, but only if I'm in very slow traffic for 10+ minutes - moving, but never stopping. Still blows clean out the tailpipe for actual emissions tests, at least. Just does it if the traffic on my commute is just right (errrr... wrong?).

-Charlie

When my 96 SR5 engine installed into my 97 would do that driving slow for extended periods of time I was burning antifreeze.


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[phattyduck]

When my 96 SR5 engine installed into my 97 would do that driving slow for extended periods of time I was burning antifreeze.

I'll check for that, but the CA emissions ECU is much more sensitive to cat/fuel issues than the Fed ECU would be. I think it still has the original Lambda/O2 sensors on there at >300k miles, maybe just time for some new ones there?

-Charlie