FZJ80 Cats - To Replace or Not Replace (1 Viewer)

[CrazyCruiser94]

Howdy all. Recently purchased a 94 LC. She’s got 275k miles on the clock and although she’s in decent shape there’s work/baselining to be done. One of those is what I suspect is an exhaust leak or bad cats or both. Biggest give away is the smell of sulfur that lingers as the truck runs. When I first got the cruiser I thought this is what these older vehicles smelled like almost like a boat motor, heavy on emissions. After some poking around I determined it’s coming from around the exhaust manifold down somewhere to the cats. I’m now laser focused on the cats being the culprit as they rattle when accelerating you can hear it inside and I also noticed the area gets HOT HOT.

With all that being said… should I spend the money replacing them? I’ve shot first now I’m asking the question. I purchased the Magnaflow direct bolt-ons (#24455 x2) but I’m still able to return if needed. Now that I read I realize folks just outright delete them with no problems as the o2 sits before the cats.

What benefits are there to just deleting? Will I still get that gas/exhaust smells if I delete? On the other hand what do I benefit from keeping them and refreshing them? I’ve read of others who noticed their engine run smoother after replacing.

What recommendations does the community have?

Thanks!

 

[pmccumber]

Well, catalytic converters burn unspent fuel. That’s what the air pump injecting in to the exhaust helps facilitate. Deleting the cats will produce significantly more harmful pollution.

I realize Texas doesn’t test but it’s nice when we all don’t piss in each others stream.

I got new Magnaflow cats, and entire manifold back stainless exhaust, 8years ago and they’ve held up fine.

 

[SoTexCruiserDoc]

FYI there are a BUNCH of threads related to the pluses and minuses of cats on MUD. Use google to search and include “IH8MUD” in the search line.

Here’s a sample thread:

Lifespan of FZJ80 Catalytic Converters?

Another good way is by measuring the o2 readings after the cat versus before the cat. The computer actually does this for you and will throw a P0420 code if it detects issues According to my Ultraguage, the truck isn't throwing any codes.

forum.ih8mud.com

A lot of the catalytic converter info come in the form of threads related to stolen cars. My cats were stolen on my ‘97 LX450 2 yrs ago. I replaced with Magnaflow option as you ordered partially because the OEM Lexus price would have EXCEEDED $5K with install, and partially to maintain the resale value of a relatively high value truck if it happened to go to a smog state at some point. With cat delete, sounds like the smell bothers some folks, even if the engine light is fixed with black electrical tape.

FYI this is a pretty big thumbs up to above comment:

 

[CrazyCruiser94]

Well, catalytic converters burn unspent fuel. That’s what the air pump injecting in to the exhaust helps facilitate. Deleting the cats will produce significantly more harmful pollution.

I realize Texas doesn’t test but it’s nice when we all don’t piss in each others stream.

I got new Magnaflow cats, and entire manifold back stainless exhaust, 8years ago and they’ve held up fine.

Well, catalytic converters burn unspent fuel. That’s what the air pump injecting in to the exhaust helps facilitate. Deleting the cats will produce significantly more harmful pollution.

I realize Texas doesn’t test but it’s nice when we all don’t piss in each others stream.

I got new Magnaflow cats, and entire manifold back stainless exhaust, 8years ago and they’ve held up fine.

Tbh I’m not big on deleting. I was already half convinced to replace as I already made the purchase. I just wanted to see what benefits there would be to deleting. This is really the wife’s truck and she HATES the smell which is a big reason it’s one of my first repairs. And I agree I’d hate to be the guy stinking up the atmosphere and possibly being louder about it too. Keeping the Magnaflows

 

[CrazyCruiser94]

FYI there are a BUNCH of threads related to the pluses and minuses of cats on MUD. Use google to search and include “IH8MUD” in the search line.

Here’s a sample thread:

Lifespan of FZJ80 Catalytic Converters?

Another good way is by measuring the o2 readings after the cat versus before the cat. The computer actually does this for you and will throw a P0420 code if it detects issues According to my Ultraguage, the truck isn't throwing any codes.

forum.ih8mud.com

A lot of the catalytic converter info come in the form of threads related to stolen cars. My cats were stolen on my ‘97 LX450 2 yrs ago. I replaced with Magnaflow option as you ordered partially because the OEM Lexus price would have EXCEEDED $5K with install, and partially to maintain the resale value of a relatively high value truck if it happened to go to a smog state at some point. With cat delete, sounds like the smell bothers some folks, even if the engine light is fixed with black electrical tape.

FYI this is a pretty big thumbs up to above comment:
View attachment 3869730

That’s nuts lol. I recently joined and decided to follow the guy literally a few hrs ago realizing the guy’s a big deal around here.

I’ve already made the purchase. The other response made a lot of sense and you added another great point about the resale potential. I would have probably steered clear myself of an LC with deleted cats. Shout out to MF for having an inexpensive replacements.

Hopefully replacing will take care of that annoying smell.

 

[smorkington]

Delete and never look back.

 

[BILT4ME]

That’s nuts lol. I recently joined and decided to follow the guy literally a few hrs ago realizing the guy’s a big deal around here.

I’ve already made the purchase. The other response made a lot of sense and you added another great point about the resale potential. I would have probably steered clear myself of an LC with deleted cats. Shout out to MF for having an inexpensive replacements.

Hopefully replacing will take care of that annoying smell.

Which cats did you purchase?
If you bought the set that's made for 95-97, you will have a bit more work with getting all the exhaust supports and touting complete.

If you bought the two individual cats, you just need to get them integrated into your pipes. There are differences from 94-95.

The 94 is side by side cats, the 95+ are inline cats.

Personally, I would replace them, particularly if the wife is driving and complaining about the smell..

 

[CrazyCruiser94]

Which cats did you purchase?
If you bought the set that's made for 95-97, you will have a bit more work with getting all the exhaust supports and touting complete.

If you bought the two individual cats, you just need to get them integrated into your pipes. There are differences from 94-95.

The 94 is side by side cats, the 95+ are inline cats.

Personally, I would replace them, particularly if the wife is driving and complaining about the smell..

I did end up going with the twin Magnaflows on their site made for the 94’. Just got them in today. I’ll be installing once I also get my new O2 sensors in. It’s a “might as well” while I’m there replacing the cats. I actually may relocate up by the exhaust manifold. I’ll keep this thread updated on whether or not it makes a difference on the smell and also maybe a slight improvement on performance aka acceleration and MPG.

 

[12bit]

I had my cats replaced with straight pipes on a 94. It sounds like a can of bees when you rev the engine near 3K RPMs. Not sure if it's an issue with the install, but I'm considering throwing on some cats again in the near future.

 

[CrazyCruiser94]

Delete and never look back.

I had my cats replaced with straight pipes on a 94. It sounds like a can of bees when you rev the engine near 3K RPMs. Not sure if it's an issue with the install, but I'm considering throwing on some cats again in the near future.

I’ll let ya know how mine perform. Curious to see if it makes any difference in smell and performance.

 

[clx16]

I have some magnaflows that are waiting to get put on. i don't care for the smell mine creates and i am pretty sure while cold the manifold to cat pip gastket is leaking a little so i have to hurry and put it on recirculate when i start the vehicle cold. anyway that is all getting replaced. so curious if I am headed in the right direction.