CEL Code 420 and Replacement Catalytic Converter / Exhaust System help

[Okie81]

I've seen a lot of people dump their 2 cat setups for a single cat with an O2 simulator

[slosurfer]

just wanted to say "f u" to all you non cali people who have to deal with our even crappier cat laws. My buddy had to spend almost $500 to get his cat replaced on his 89 toy truck because of our stupid laws.

[Erich_870]

just wanted to say "f u" to all you non cali people who have to deal with our even crappier cat laws. My buddy had to spend almost $500 to get his cat replaced on his 89 toy truck because of our stupid laws.

Right back at ya buddy!

I was about to purchase the lower dummy O2 sensor, but after Bruce shared muffler express, I figured I'd just replace the stock system.

Erich

[corax]

My buddy had to spend almost $500 to get his cat replaced on his 89 toy truck because of our stupid laws.

Wow, I think your buddy got ripped. Smog ref never gave my $50 JCWhitney cat a second glance when he was doing the inspection for my engine swap.

[Erich_870]

So it's time for me to bring this thread back from the dead. I've been procrastinating on having my cat's replaced but my MIL's timing belt failure has motivated me to get my long list of work done.

I've had the new cats sitting in my garage for almost a year now partly because I was using my rig for work and couldn't spare the down time, but also because the cats came with a notice that said in large letters "STOP, FAILED CATS COME FROM FAILED EMISSION COMPONENTS UP STREAM! DO NOT REPLACE CATS UNTIL YOU'VE REPAIRED THE PROBLEM THAT MADE THE CATS FAIL!!"

What problems should I look for to follow their imperative message?

Erich

[MTL_4runner]

So it's time for me to bring this thread back from the dead. I've been procrastinating on having my cat's replaced but my MIL's timing belt failure has motivated me to get my long list of work done.

I've had the new cats sitting in my garage for almost a year now partly because I was using my rig for work and couldn't spare the down time, but also because the cats came with a notice that said in large letters "STOP, FAILED CATS COME FROM FAILED EMISSION COMPONENTS UP STREAM! DO NOT REPLACE CATS UNTIL YOU'VE REPAIRED THE PROBLEM THAT MADE THE CATS FAIL!!"

What problems should I look for to follow their imperative message?

Erich

I wouldn't worry too much about the warning, the cats typically fail for 2 reasons:
1) Air getting in upstream of the cats (ie damaged gaskets, hole in exhaust)
2) Excess fuel being dumped into the cats (bad O2 sensor, injectors, MAF, etc)

Do your best to look over everything and then go ahead and install them.

[Erich_870]

I wouldn't worry too much about the warning, the cats typically fail for 2 reasons:
1) Air getting in upstream of the cats (ie damaged gaskets, hole in exhaust)
2) Excess fuel being dumped into the cats (bad O2 sensor, injectors, MAF, etc)

Do your best to look over everything and then go ahead and install them.

That's good to hear. I've had both a bad MAF and O2 sensor prior to this so that is my hope.

Erich

[Erich_870]

I had the cats replaced yesterday along with other tune up items (new T-belt, plugs/wires, oil change, and block heater) and the rig drives great now!

I did have a small issue where there was a loud resonance sound that happened at 10 and 20 mph, so I swung back by the shop. One of the O2 sensors was just barely touching a heat shield on the cat so they tweaked it a little and now it’s fine.

Here are some pics:

I couldn’t see down the inlet side, but here’s what the catalytic core looks like stock. My replacement cats have a square pattern with slightly larger holes. I can hear a difference in the engine sound now, it sounds more “throaty”

[img width=800 height=600]http://i7.photobucket.com/albums/y261/Erich_870/Toyota%204Runner/CatyliticConverter.jpg[/img]

[img width=800 height=600]http://i7.photobucket.com/albums/y261/Erich_870/Toyota%204Runner/2011-03-31115330.jpg[/img]

Erich

[20005spd]

the front cat is steel and looks like its wound in a circle. the rear cat is the one doing most of the work, with the expensive metals, and honeycomb shape. i replaced both of mine recently with a single universal cat and yes the sound is fun and no check engine light since

[Erich_870]

the front cat is steel and looks like its wound in a circle. the rear cat is the one doing most of the work, with the expensive metals, and honeycomb shape. i replaced both of mine recently with a single universal cat and yes the sound is fun and no check engine light since

Interesting. I assumed both cats had precious metal in them. What does the front cat do then, just get hot and help burn off remaining fuel/C0?

I'll have to snap a pic of the second cat to look for differences in the core shape.

Erich