3rd gen Cali exhaust and emissions

Nimic13

Nimic13

New member
Ok so I'm having an issue and being told a million different things so I'm here to just get to the bottom of all this,fix my problem, move on.

I have a 96 4Runner in California. Now I had 1 cat and a muffler with one o2 before the cat and one after. Now I went to smog it, and they told me "you need 2 cats, says here on this sticker under your hood". Ok fine. Went and got another cat from a 4Runner stock exhaust and welded that on up there. Cool . Went to smog, "nope second cat is in wrong spot. Needs to be before the second o2" -_- fiiiine so I cut the whole thing down a little after the first o2 and cut everything up to fit 2 cats in between both the o2 sensors. Now here's my issue. I don't see how the hell these will both fit and the second o2 reach unless I literally weld them all touching each other. Can I weld them all that close? How the hell did the stock exhaust have 2 cats there?? Do I even need 2 cats? I'm lost. I just need my damn car smogged. Any help will be awesome.


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Nimic13 said:
Ok so I'm having an issue and being told a million different things so I'm here to just get to the bottom of all this,fix my problem, move on.

I have a 96 4Runner in California. Now I had 1 cat and a muffler with one o2 before the cat and one after. Now I went to smog it, and they told me "you need 2 cats, says here on this sticker under your hood". Ok fine. Went and got another cat from a 4Runner stock exhaust and welded that on up there. Cool . Went to smog, "nope second cat is in wrong spot. Needs to be before the second o2" -_- fiiiine so I cut the whole thing down a little after the first o2 and cut everything up to fit 2 cats in between both the o2 sensors. Now here's my issue. I don't see how the hell these will both fit and the second o2 reach unless I literally weld them all touching each other. Can I weld them all that close? How the hell did the stock exhaust have 2 cats there?? Do I even need 2 cats? I'm lost. I just need my damn car smogged. Any help will be awesome.


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There is no way a '96 had two cats. The first two-cat MY was 1999--maybe a few EOY '98s were Cali. two-cats. Can you post a pic of your emissions info label under the hood? Look at the line under Engine Family in the top left corner. If it says something like SFI, A/F, TWC(2), HOS...it's a Cali. two-cat. If it says something like SFI, HOS(2), TWC it's a Federal one-cat system. (TWC is Three-Way Converter.) I'm pretty sure ALL '96 were one-cat Federals. If I see the pic, or you post the engine family number, I can check the CARB data base and confirm what years it goes with. Maybe your hood got swapped.

The way the Cali'.s are put together, the front sensor, which is an Air/fuel wideband sensor, not an O2, has its bung IN the front cat, and is up a vertical curve so the front sensor is way closer to the engine than the one-cat system where the front sensor is in the pipe. Then the inlet pipe to the muffler is also a lot shorter. That's how it fits in. What cats did you put in? The Cali. front cats and rear cats are not the same and they were designed to work together. It's not just two normal cats one after the other.

Something is very wrong here. Please post that sticker pic.
 
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TheDurk said:
There is no way a '96 had two cats. The first two-cat MY was 1999--maybe a few EOY '98s were Cali. two-cats. Can you post a pic of your emissions info label under the hood? Look at the line under Engine Family in the top left corner. If it says something like SFI, A/F, TWC(2), HOS...it's a Cali. two-cat. If it says something like SFI, HOS(2), TWC it's a Federal one-cat system. I'm pretty sure ALL '96 were this one-cats. If I see the pic, or you post the engine family number, I can check the CARB data base and confirm what years it goes with. Maybe your hood got swapped.

The way the Cali'.s are put together, the front sensor, which is an Air/fuel wideband sensor, not an O2, has its bung IN the front cat, and is up a vertical curve so the front sensor is way closer to the engine than the one-cat system where the front sensor is in the pipe. Then the inlet pipe to the muffler is also a lot shorter. That's how it fits in. What cats did you put in? The front cats and rear cats are not the same and they were designed to work together. It's not just two normal cats one after the other.

Something is very wrong here. Please post that sticker pic.
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Here's the hood sticker. I'm thinking it did get swapped because the guy at the smog shop tried to look it up and said nothing in the 96 range was even coming up.
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Nimic13 said:
Here's the hood sticker. I'm thinking it did get swapped because the guy at the smog shop tried to look it up and said nothing in the 96 range was even coming up.

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Thanks for the pic.

Huh? It's not a Cali, does not use an A/F but calls for two cats? Call me bamboozled. I will do some research and get back to you.
 
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TheDurk said:
Thanks for the pic.

Huh? It's not a Cali, does not use an A/F but calls for two cats? Call me bamboozled. I will do some research and get beck to you.
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It came up as non Cali?? That's weird. I wonder if I should just weld the 1 cat back up and leave it was and tell the smog guys to just run the damn test and it should pass if 96s never required 2 cats....right?


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Scramble said:
that's efed up, I would have bet money that the first 2 cat was a 99 Cali model. My NY 99 is one cat.
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Yeah I know. But I swear it's a one cat cause there's NO way in hell 2 cats even on a factory stock exhaust would fit in between the 2 o2 sensor connectors. It's not possible unless everything was like 1" apart from one another and that's still pushing it, trust I've measured. So I'm just trying to figure out what to do. Throw my one cat on there and tell the bastards to just smog it anyways or am I screwed and have to figure what the hell is wrong with my car.. The clock is ticking on this too because I have to pay the registration dues and the longer I wait the more they will be


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Nimic13 said:
It came up as non Cali?? That's weird. I wonder if I should just weld the 1 cat back up and leave it was and tell the smog guys to just run the damn test and it should pass if 96s never required 2 cats....right?


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The label says it's a non-Cali. And there is no EO (Executive Order) in the CARB data base for 1996 with that engine family so that is confirmed, it's Federal. But the TWC+TWC is just weird and that's what's causing your issue with smog. You have to conform to how it was built even for a non-Cali'and that says it was built with two cats. But I only see single-cat exhaust systems for 1996. So I'm still bamboozled. I'd like to try with the VIN, if you feel comfortable sending it to me in a PM, and see if I get a listing for two cats. I doubt I will, though.

At that point, I don't know what to tell you. Maybe you need to talk to a a dealer and see what exhaust they would try to sell you. If it's a single, show them the label pic and ask what gives? Maybe you could get a letter saying the label is effed up and it takes a single cat. I really don't know. Hopefully somebody else knows more than I do.

But yeah, you should pass a tailpipe test. But that alone won't make CARB ignore that TWC+TWC on the label.
 
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Heh. Found the answer for you.

Been doing a little research and it appears "TWC+TWC" refers to a type of converter design intended to extend the life of the converter, in particular the rhodium based catalyst section.
It consists of two stages- the first half being a palladium based catalyst which operates as a three-way catalyst and the second half being the traditional platinum and rhodium based three-way catalyst.
It's sometimes written as "TWC/TWC", particularly on the converter manufacturer's specs.
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so basically, it's like having 2 cats in 1 housing.
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All is well.

Wife took the truck to the DMV. The tech at the DMV said the smog tech was an idiot, and if he had looked up the truck in his book (which is apparently provided to all smog stations by the state) he would have seen that it only requires a single cat.
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1998 4runner 3.4: emissions sticker drama - YotaTech Forums

Put your truck back the way it was and tear that lamebrain a new one. I KNEW they only had one cat in 1996.
 
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Nimic13 said:
Sweeeeet. So now how do I know if I have the right cat? I have 2 different cats so one has to work


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Well, who made them and what are their part numbers? Are they CARB approved for that year and truck?
 
TheDurk said:
Well, who made them and what are their part numbers? Are they CARB approved for that year and truck?
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These are the 2 I have. The smaller one definitely looks like the 2 sectioned cat and that was the one that was on there so I think that's the one I'll use
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Seems to me that is a Federal 4runner as opposed to a CALI 4runner. When I had my Supra I had to deal with smog a lot, and also knew a lot of other owners who dealt with smog a lot. My advise is put it back to stock, toyota parts. Non-OEM cats tend to not work as well as the Toyota ones because the Toyota ones tend to use much more expensive catalysts. Many of guys were experimenting with aftermarket high flow cats, but it was really challenging to get them to pass, both visual and emissions. Many would switch everything back to stock every 2 years to pass smog and them switch everything back out.

Also if you have an intake and still have the OEM I would stick that back in. Just easier to do that deal with the smog guy.

My "smog" dance normally consists of replacing air filter, spark plugs(I use coppers on my mr2), oil change, and check the timing. If you haven't replaced the 1st O2 sensor in the last 90k miles I would do that as well (possible benefit of better gas milage too). The Fed's O2 is cheap, make sure you get the right one. My Cali 02 sensor was about 100 bucks, think the fed is like 30 bucks.

Also the 2 cat system isn't just "2 cats". It's a precat and then a main cat. The pre-cat is designed to heat up really quickly, it is generally located just off the header and is designed to target a certain form of air pollution(I forget what it was). It is followed by a main cat that does more of the general "cat" things.
 
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