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-   -   Aftermarket cat converter advice needed (https://www.toyota-4runner.org/3rd-gen-t4rs/267946-aftermarket-cat-converter-advice-needed.html)

mcaz5 01-26-2019 05:11 PM

Aftermarket cat converter advice needed
 
Think my cat(s) are finally biting the dust. I replaced both o2 sensors around 3 years, 40k miles, ago and that caused the P0420 to go off for a short time but it's mostly remained on during that time.

Driving home the other day when trying to accelerate up a hill at highway speeds. Downshift and RPMs around 3500 when all of a sudden I get this horrible grinding, metal fragment, screeching sound that sounds like it's coming the area near the cats. Back off the throttle and noise stops but then I have to give it a lot of throttle to maintain 60mpg going up a slight incline. Took the backroads home and made it home fine going around 50mph.

Searched around a bit and found a thread where the user removed the front o2 sensor and noticed improvement during acceleration, replaced the cats and he was good to go. I did the same for mine and noticed some definite improvement but didn't drive as easy as it should.

Any advice on which cats to go with? I've got a 2001 supercharged 3.4 v6 with 2 cats. It seems most people go with Magnaflow, Walker, or Eastern. If you have these how are they holding up? Curious about part numbers and if you've replaced with aftermarket cats did you use the direct bolt on fit or the universal weld on fit? Thought about having them welded on as I don't feel like dealing with the rusty PITA bolts. I would have a local shop weld them on most likely. They just recently charged me $30 to have my new Borla muffler welded on.

Any advice would be greatly appreciated. Thanks!

T4R2014 01-26-2019 05:22 PM

I have a Walker. Heat shields may rust off over time. Avoid the cheapest ebay POS.

mcaz5 01-26-2019 05:36 PM

Quote:

Originally Posted by T4R2014 (Post 3218019)
I have a Walker. Heat shields may rust off over time. Avoid the cheapest ebay POS.

Did you go with the direct fit?

T4R2014 01-26-2019 07:18 PM

Quote:

Originally Posted by mcaz5 (Post 3218029)
Did you go with the direct fit?

Yup. I don't bother with muffler shops anymore. The prices they charge around me end up breaking even with direct fit.

2ndhandyotaman 01-27-2019 12:04 AM

I used Bosal direct fits from RockAuto last year, they bolted up perfectly and have been working well so far. Nice thick flanges and good welds everywhere.

dogtail 01-27-2019 09:28 AM

I installed Walker cats also (Cali with 2), stainless bolts and double lock nutted entire exhaust.

MaineRunna 01-27-2019 10:06 AM

The most common cause of P0420 is an exhaust leak near the cats or O2 sensors. The flanges on Toyotas always rust to the point that the gaskets won't seal anymore. Sometimes the converter shell rusts out where the heat shield is welded on. If the converter has broken apart inside you should be able to hear it rattle when revving the engine in neutral or just banging on it with your fist or a rubber mallet. You could also remove it and look inside to see if it is plugged. A really plugged converter will cause a loss of power at first eventually causing stalling or even no start. Removing the O2 sensor on a totally plugged converter will allow it to breathe enough to be driven, but will not run perfect due to one of the most important sensors in the engine being removed from the exhaust pipe and thus no doing its job. If you have to replace the converter I would recommend the Magnaflow. It's high flow, all stainless steel and 2.5" all the way through.

RumHam26 01-27-2019 12:39 PM

I put on the Eastern CARB compliant direct fit set from Rock Auto and they have been hold up well for about a year and a half so far.

arbys 04-18-2019 08:03 PM

How did everyone deal with getting the nut or bolt off the upper right of the flange as as you look from the bottom? It's so tight in there that I have ruined the nut and can't get it off.

MaineRunna 04-18-2019 08:40 PM

Quote:

Originally Posted by arbys (Post 3274383)
How did everyone deal with getting the nut or bolt off the upper right of the flange as as you look from the bottom? It's so tight in there that I have ruined the nut and can't get it off.

Acetylene torch and six point swivel sockets. If you don't have that stuff take it somewhere.

dogtail 04-19-2019 07:36 AM

1 Attachment(s)
Quote:

Originally Posted by arbys (Post 3274383)
How did everyone deal with getting the nut or bolt off the upper right of the flange as as you look from the bottom? It's so tight in there that I have ruined the nut and can't get it off.

If you are junking your front cat, you can cut it off with a SawsAll near the studs. And any nuts you wrecked, use a Map Gas bottle torch heat the stud/nut up repeatedly if needed and wiggle it back and forth til you can unscrew it with Visegrips or whatever will grap it, stud and all, or if stud stays on, you can keep it on, but nice if you can get it out. Autozone sells a stud kit for these with brass nuts thats wont rust up....but the stud kit has different threads than the original, so you can't just use the nuts.

19963.4lsr5 04-19-2019 08:20 AM

Those brass nuts strip before the required torque. I tried them


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19963.4lsr5 04-19-2019 08:30 AM

That P0420 code is also caused by antifreeze. And there is only one place that comes from. My 97 gave me that code constantly from a rusted cylinder liner allowing antifreeze consumption.

Same CAT and a rebuilt engine the readiness monitor for the CAT cleared in 6 miles of driving at 60mph. Itís only been around 1000 miles since the engine swap but as fast as the readiness monitor set Iím not worried about a bad CAT


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dogtail 04-19-2019 08:33 AM

Quote:

Originally Posted by 19963.4lsr5 (Post 3274587)
Those brass nuts strip before the required torque. I tried them


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No problem for me on multiple uses, and removals.

19963.4lsr5 04-19-2019 03:54 PM

Quote:

Originally Posted by dogtail (Post 3274594)
No problem for me on multiple uses, and removals.



I wish I could say the same.


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