08 SR5 V6 4Runner Catalytic Replacement worth it?

So, for starters; I live in an area that does not do emissions testing, so as far as passing my inspection goes I am still technically fine for it. But I am thinking of finally addressing the failed catalytic converter and either replace it or remove it altogether.

would like some advice from individuals who live in areas that don’t do emissions testing on how to go about this. Probably looking to spend 2500 for a catalytic replacement if I absolutely have to.

(Btw this 4Runner just made it to its 200k miles). I’ve heard having a faulty cat converter can lead to increased smog in your vehicle and lower mileage, but I’ve also heard it doesn’t affect anything other than just allowing you to pass emissions. Additionally, people have reported that replacing a failed catalytic converter with a straight pipe or something along those lines will yield better economy and horsepower (though some claim it’s negligible).

TLDR: If you didn’t have to pass emissions testing and your catalytic converter died on your 200k mile 4Runner would you replace it? Ignore it? Delete it?

 

I’d do it to keep emissions cleaner and CEL’s away (I’m assuming no cat or poor cat performance trips a CEL) IF I was planning to continue to keep the vehicle indefinitely as my daily - if nothing else just to keep the different smells, gases away from me and those around me.

Just my opinion though, I do live in an area with emissions, so whoops! I know $2,500 is a hefty chunk of change.

Is a CEL the only negative effect you’re experiencing right now?

 

Pretty much yeah the CEL is the only indicator of a failed catalytic converter. I don’t really smell any of the described indicators I should look out for (foul and sulfur smells) in the cabin, maybe the one thing I’ve noticed is my mileage has gone down slightly, but that’s about it. Unless I’ve become acclimated to the smell already lol.

Though, I did read that you can do something with a sensor to make the CEL go off but I’m not entirely sure on the details of that.

 

I am not expert on this but I read the upstream and downstream O2 sensors are linked with cat converter which is linked to your injectors and affects fuel delivery. You do not want too lean or two rich in combustion chambfer. I would talk with electromechanics that assess and repair emission systems.

 

This is in line with what I’ve heard as well (and what I’ve noticed too), which is why I’m even considering replacing it when most people just go with a straight pipe or ignore the cat in this state. But you make a good point, something to bring up to my mechanic

 

As a related issue , years ago my GMC Sierra 6.0 stake bed was driven cold all the time out and into its parking spot inside shop. Used rarely on the road/ freeway.
It backfired ofen and loudly. The backfire broke up the cat converters (both) and the pieces tumbled in the steel shell until small enought to blow out tailpipes.

 

On a 17 year old vehicle without an emission testing requirement, I would just run it with the existing CAT in place. The only reason to do anything to the CAT is if the honeycomb inside has melted and is obstructing flow - you would see a significant loss of power if that was happening. In that case, you could take a pipe and break up/knock out the honeycomb to provide unrestricted flow. Unlikey that is a problem.

You do need an operational upstream O2 sensor - that is the one that provides feedback to adjust the fuel delivery. The downstream O2 just monitors the CAT performance and does not control anything so no need to worry about that one. If you are concerned that your CEL being on all the time will prevent you from picking up on a new code being set, install a ScanGauge and review the codes periodically.

 

Are you SURE you have a failed catalytic converter? It could be a faulty sensor.