Emission specs

Nick M

Black Rifles Matter
Sep 9, 2005
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I could probably find it in my library. You can probably find it with google. My hint for you is that they don't change. Meaning the spec in 1988 still applies. Or whatever year you have. And if the inspectors are doing their job, they will fail visual if you don't have both cats, EGR, or the EVAP. I say that because I read here a lot of people removing the items.
 

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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Fullerton,CA
I believe you only need to have 1 working cat in place in CA. Tho the 2nd one would prolly help your chances so long as its good and up to temp.
 

Nick M

Black Rifles Matter
Sep 9, 2005
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You are required to have two working cats in all of the USA if that is how your car came from the factory. When you pass with out, it is becasue the inspectors are not doing as required.
 

radiod

Supramania Contributor
Dec 13, 2007
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^

The rule is supposed to be that the exhaust is supposed to remain stock until the last emissions system (eg, the catalytic converter). Thus enter the catback exhaust system and why they are so popular.

So yes, you can get past the test readings with one good cat, but technically you are still failing. How many get caught with a non stock downpipe? Not many due to the fact that most inspection places (that I've seen at least) won't even bother to pop your hood and just run a mirror on a stick under the car to make sure some metal bulge is about half way down the exhaust system. Technically it's still a fail though.
 

Nick M

Black Rifles Matter
Sep 9, 2005
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The StL isn't doing IM240(they should be) on anything. The OBDII cars are doing a computer check only. And you can't cheat it unless you write the software. After no failures are verified by the MIL, the readiness codes are checked to see that a drive cycle has been done. Our cars only get a safety. I have an aftermarket downpipe, but the main cat in place.
 
Oct 11, 2005
3,819
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Thousand Oaks, CA
California has tightened the specs over the years for the MK3. Its pretty weird. My HC limit at 15mph went from 105 to 75 ppm last year. I have all the old tests from when they first started dyno testing.

HC Max at 15mph:
year 86 87 88 89 90 91 92
================================
Auto 115 93 97 76 75 75 106
Man 113 106 106 85 106 106 106