catalytic converter questions

[mikehallbackhoe]

my 84 crx 1300 comes with what they call a oxidation catalyst, to convert HC and CO into CO2, amn water vapor. the 1500 came with a three way catalyst to convert HC, CO, and NOx into CO2 and water vapor. My owners manual says it can be overheated and damaged if it's fed too much unburned fuel mixture from the engine, so don't push or tow the car to start it, and don't turn the key off while the engine is running above idle speed. My question is, will EOC ruin the catalytic converter?

[mcrews]

seem like that's what the manual is saying

[IsaacMTSU]

That's what it sounds like, but I'm not sure why roll starting it would hurt... Seems like maybe flooring it a lot at high RPM would be bad about feeding it lots of hot unburned fuel mixture.

[Ryland]

You should never turn the key off while the engine is above idle, I always take my foot off the gas pedal and press the clutch in until RPMs drop to idle, then turn the key off.
As for popping the clutch to start it, I've never heard of that harming anything and don't see how it could.

[drmiller100]

sir, your cat is 30 years old. Don't tell anyone, but it is already dead. don't worry - no one will ever know

that was one of the first cars with cats, and everyone was worried about them and what would hurt them over time.

since then they have figured out cats are a bit tougher then they thought, but after 15 or 20 years or 100k miles most cats are pretty well shot.

in 96 the EPA figured out dual 02 sensor circuits to monitor the cats and throw engine codes when the cat is shot or the dual 02 sensor circuit has a malfunction.

[mikehallbackhoe]

It passed smog ,but the ccvc engines were pretty clean anyway. It has 133,000 miles on it. the cat mounts right to exhaust manifold, so it probably gets pretty hot. I might see how hard it would be to pull it and check to see if it is burnt out.

[IsaacMTSU]

I was thinking the same thing about my CRX. The cat is right there on the exhaust manifold, it's probably useless now, but it seems like it would be a pain to get it out.

[mikehallbackhoe]

if the cat is burnt out, replacing it with a straight pipe would be more efficient than an open chamber inside the cat, and if it is plugged up, a pipe would also be better.

[mechman600]

Originally Posted by mikehallbackhoe

I might see how hard it would be to pull it and check to see if it is burnt out.

Often when a cat is "dead", you cannot tell my just looking at it. It may look fine visually, but the precious metal coating is simply worn out. If you want to go cheap and have some welding skills (or know someone who does), maybe try a generic eBay cat.

[mikehallbackhoe]

I took a look at what it would take to remove it, and it envolves major surgery! I will leave it alone til I can get my mechanic to look at it. It runs good, doesn't overheat, and is getting me 50 mpg.