Cat converters failed, SAIS air induction bypass

[LCCygnus]

Currently talking to a seller with an 06 LC out of state who said he had his catalytic converter and SAIS fail, but didnt need to pass emissions so he replaced the cat with a standard pipe and installed the Hewitt Tech air induction bypass system.

What would be the cause of this failure? Anything other kinds of issues that i should look aside from the normal checklist?

Will it have any problems in the future?

Thank you guys for any advice or experience.

 

[jerryb]

I would never believe an owner/seller that told me the cats failed, so I put in straight pipes.
The air bypass thing isn't related, but could have happened at the same time, or because of his issue.
IF you believe a piece of plastic impeller could travel all that way and actually reach the cat then I guess it could have been the result of one event.
I don't believe it's possible given the travel path.

At worse you could need two cheapy cats, sort the o2 sensors, assume his failed or one or more aren't working anyway which might have been his issue from the beginning.
If you have emissions in your county or city you should be more concerned than if you don't. Maybe he would be honest with you and tell you if it would pass emissions. depends.
(if you buy it, I would buy your straight pipes if you didn't want them)

I would look at the bypass pipes, the bolts and nuts, 3 header side, 2 mid pipe side.
also, all 4 o2 sensor bungs in the pipes and the sensors themselves or the blank connectors where they use to be. ALso the exhaust manifolds where the secondary intake meets them, and the junction with the aluminum pipe that travels up right behind the engine. That's a small pipe with a two bolt flange. Look up and close to the wheel well right where the exhaust manifold meets the cat pipe. That is also where block off plates are installed. You can see them if you know what your looking for.

if you bought an 06 with missing cats, missing o2 sensors, all, and an SAI code. YOu could fix all that for less than a thousand if you wanted legal emissions. Aftermarket cats. denso narrow band o2 and stock wideband, or denso if I could prove they were toyota specific reference voltage. Nuts, studs and gaskets if you don't reuse are a little bit of money also, bypass kit I think is <200. IF you have an 06-7 you want that bypass kit anyway.
I'd buy a car like that no problem. I'd ask for 600$ off, considering selling the straight pipes, and someone already bought the SAI bypass kit and installed it and the block off plates, hopefully.
I'd hook up techstream and look a data before buying also. A bluetooth obd could get you AFR or lambda numbers, assuming the front sensors are still in place, if you couldn't get a laptop there and use techstream.
Don't be scared off if everything else on that one is good and you really like it.

 

[hewitttech]

Most likely not the SAIS that caused the CAT failure but it has been blamed before. The belief is that plastic pump bits could get to and damage the beds. More probable the exhaust system suffered a rock strike and the shock shattered the catalyst bed. Another common thing that causes the demise of cats are blown head gaskets and severely out of tune engines pretty much dumping fuel. A crappy running engine, poor quality fuel and exhaust leaks can also result in the catalyst getting clogged up. Then again some people will just do it because they think it will make a lot more power. I will likely be doing my GX soon because the cracked manifold is driving me nuts. I really just wish DT could make a bolt in shorty with cats... they won't I have asked.

 

[AlpineAccess]

With the number of Land Cruisers with 350k+ miles on stock cats, this guy is full of it or as noted the motor has had serious issues.

 

[jerryb]

Yup.

 

[LCCygnus]

Most likely not the SAIS that caused the CAT failure but it has been blamed before. The belief is that plastic pump bits could get to and damage the beds. More probable the exhaust system suffered a rock strike and the shock shattered the catalyst bed. Another common thing that causes the demise of cats are blown head gaskets and severely out of tune engines pretty much dumping fuel. A crappy running engine, poor quality fuel and exhaust leaks can also result in the catalyst getting clogged up. Then again some people will just do it because they think it will make a lot more power. I will likely be doing my GX soon because the cracked manifold is driving me nuts. I really just wish DT could make a bolt in shorty with cats... they won't I have asked.

With the number of Land Cruisers with 350k+ miles on stock cats, this guy is full of it or as noted the motor has had serious issues.

Any links to others having these experiences?

 

[Mark WV]

It seems to be common for the 06-07 models to throw a P0420 &/or P0430 code (cat efficiency below threshold bank 1 / bank 2).

there is one very long thread on the subject if you wish to review, P0420 and P0430 - 2006 LC
sometimes traced to bad upstream AF senors or downstream O2 sensors, also could be caused by leaks in the intake manifold O rings, or general poor tune of the engine.

I doubt the cats were bad, but these codes can lead one to believe they are resulting in their replacement.

If you are concerned about emissions, then aftermarket cats and new sensors will set you back about a grand. As for the bypass kit, they work great - just leave it in place.

 

[AlpineAccess]

Any links to others having these experiences?

Here's the high mileage thread:

Post your high-mileage 100-series!!!

1998....barely broken in. 2.02.09

forum.ih8mud.com

If looking for those with issues with CAT's I would use search to find the handful of threads out here. Most of them detail a poor run condition, terrible gas mileage, a CEL on that they've been clearing constantly, bad O2 sensors, etc.

 

[pgs0001]

@LCCygnus Did you ever go look at this vehicle? I think I am looking at this same truck and have some similar concerns to you regarding the Cats. The SAIS bypass doesn't really bother me but the claim that the cats failed as a result of the SAIS is highly unlikely. I am in AL and we don't have emissions testing so its not that big of a deal but still concerning if there is a greater underlying cause.

 

[LCCygnus]

@LCCygnus Did you ever go look at this vehicle? I think I am looking at this same truck and have some similar concerns to you regarding the Cats. The SAIS bypass doesn't really bother me but the claim that the cats failed as a result of the SAIS is highly unlikely. I am in AL and we don't have emissions testing so its not that big of a deal but still concerning if there is a greater underlying cause.

The vehicle is a black 06 LC with no AHC and no cats located in TN.

He had no good explanation for why the ahc and cats were ripped out and seemed like he just cheaped out. Not confidence inspiring.

Its rust free and i was very close to pulling the trigger because I'm sick of looking but I ultimately decided to pass because the cats failing could be at best a poorly running engine dumping fuel or at worst a headgasket issue.

Look up some videos on YouTube about why cats fail.

I need something reliable to daily as I further my education.

 

[J1000]

He had no good explanation for why the ahc and cats were ripped out and seemed like he just cheaped out.

He probably just took advice from this forum