two o2 sensors and I'm getting ready to hollow out the cat.

[nickster]

So that bright little orange light in the cluster is really starting to piss me off...

"P0421 - Bank1 warm-up catalyst" is what the computer came up with.

Both O2 sensors have already been changed... bank 1 was changed after the light came up, thinking that would fix the issue but it didn't.

I've checked the spark plugs and they're all good. All that's left is the catalytic converter... I really don't want to spend money on getting a new one.

So my question is, do you think it's wise to hollow-out the cat? Do you think it will fix the issue? I'm just afraid of doing this and the problem still being there and/or possibly making the car sound like complete ass.

Just FYI, I just finished dropping in a rebuilt motor. My old motor used to smoke like hell, so I'm also thinking the cat is clogged as ballz!

Any input is much appreciated!

 

[slavrenz]

Hollowing out the cat won't do anything except make your exhaust a heckuva lot louder. The rear O2 sensor monitors the emissions after the cat - if they match the emissions read by the first O2 sensor too closely (i.e., the cat's not doing its job), you'll get the P0421 code. This is why hollowing out the cat is a waste of time.

Do a search on here for the spark plug nonfouler fix. People who install headers with no cat use this to keep the light off. Essentially, you move the rear O2 sensor out of the main exhaust stream by installing a spark plug nonfouler between it and your exhaust pipe.

Like I said though, search for this solution instead. If you go this method, you can still hollow out your cat if you think it's clogged, but your car's gonna be hella loud.

 

[nickster]

Hollowing out the cat won't do anything except make your exhaust a heckuva lot louder. The rear O2 sensor monitors the emissions after the cat - if they match the emissions read by the first O2 sensor too closely (i.e., the cat's not doing its job), you'll get the P0421 code. This is why hollowing out the cat is a waste of time.

Do a search on here for the spark plug nonfouler fix. People who install headers with no cat use this to keep the light off. Essentially, you move the rear O2 sensor out of the main exhaust stream by installing a spark plug nonfouler between it and your exhaust pipe.

Like I said though, search for this solution instead. If you go this method, you can still hollow out your cat if you think it's clogged, but your car's gonna be hella loud.

I just found that thread for the fix... nice find!

But thing is that I still have the stock headers on the car right now. Even though that nonfouler fix seems like it will work, I'm afraid I'm just hiding the problem.

BTW, you totally convinced me on not hollowing the cat, thanks!

 

[stealth]

I just found that thread for the fix... nice find!

But thing is that I still have the stock headers on the car right now. Even though that nonfouler fix seems like it will work, I'm afraid I'm just hiding the problem.

BTW, you totally convinced me on not hollowing the cat, thanks!

The non-fouler trick is only going to fool the ECU into thinking that your cat is working. If you want to actually fix the problem then you need to get a new cat.