# How can I be sure catalytic converter really needed to be replaced?

**URL:** <https://community.cartalk.com/t/how-can-i-be-sure-catalytic-converter-really-needed-to-be-replaced/60436>\
**Category:** Maintenance/Repairs\
**Tags:** catalytic-converters, cr-v, honda\
**Created:** [January 25, 2011, 1:08am UTC](https://community.cartalk.com/t/how-can-i-be-sure-catalytic-converter-really-needed-to-be-replaced/60436 "2011-01-25T01:08:43Z")\
**Posts on this page:** 1\
**Showing post:** 16

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**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\
**Post date:** [May 23, 2017, 11:45pm UTC](https://community.cartalk.com/t/how-can-i-be-sure-catalytic-converter-really-needed-to-be-replaced/60436/16 "2017-05-23T23:45:09Z")

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> [@irlandes](#):
>
> Something has to be wrong to wipe out a cat. It might be an engine running too rich which burns the rare metals. It might be oil or some other sort of contamination.

I tend to disagree with that

I’ve encountered several older vehicles which burn on oil, aren’t running rich, in fact the engine is and always was in perfect mechanical shape. yet the catalytic converter can NOT clean up the emissions enough to pass the smog test

Now let me be more specific . . . these vehicles I’m thinking of don’t have absolutely wasted, plugged up cats, which are literally slowing it down on the freeway

They drive just fine, power is normal, no smell, they are no longer effective at cleaning up the emissions well enough to pass that smog test

the before and after results of the 5 gas analyzer also prove it

But what do I know . . . ?

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