How to tell if you need a new catalytic converter?

[datsa]

So, are there ways to tell if I need a new cat? Have 4AFE engine, California-spec cat. But my car is not as peppy as it used to be, a bit sluggish on acceleration, and makes me wonder about the cat finally clogging up after 204K miles.

So far, the engine is not throwing any codes (the check engine light CEL is not on), but I don't know if these 6th gens threw codes for a cat.

Timing and idle seem okay, fuel economy is normal, small oil leak from front main seal, but it's been there forever. Accelerator linkage seems to be normal. No known hose leaks.

New plugs. I rebuilt the distributor, but this problem was occurring before I rebuilt it.
I'm replacing the fuel filter in the next few days.

[Rookie_One]

they dont throw a code for a cat (viva OBD1)
possible thats the muffler that is clogged

[eage8]

if the cat is clogged it should get a lot hotter than normal (I've seen the glow before)

[Donald]

Originally Posted by eage8

if the cat is clogged it should get a lot hotter than normal (I've seen the glow before)

LOL. On an RX7 right?
I remember that there was talk of them were starting grass fires back in the old days. I never found out if that was true.

[eage8]

Originally Posted by Donald

LOL. On an RX7 right?
I remember that there was talk of them were starting grass fires back in the old days. I never found out if that was true.

yeah... lol, it was a California model with 3 cats haha.

rotarys run a bit hotter than normal cars... that's why mine doesn't have any cats

[Ghostyman]

Have you checked the compression in the cylinders? I'd look there before guessing it's the cat.

You can kind of test if the cat is clogged by unbolting the O2 sensor and see if that helps it. The exhaust can then exit the O2 sensor hole and it should run better.

And yeah, they sure can start fires. Don't park over tall, dry grass.

[datsa]

Originally Posted by Ghostyman

Have you checked the compression in the cylinders? I'd look there before guessing it's the cat.

You can kind of test if the cat is clogged by unbolting the O2 sensor and see if that helps it. The exhaust can then exit the O2 sensor hole and it should run better.

Yeah, I am planning on testing cylinder compression -- I should have thought of that first; the reason I thought of the cat was that two years ago my car barely passed smog. Today, it passed with decent results, but high in hydrocarbons and low in CO. Your suggestion makes sense; I hope the piston rings aren't going . . .

All components checked out fine, including the cat converter.