I failed smog with my stock 96 civic ex.The dude said my cat is bad which I thought it was because it sounds like its all broken up In the body of it.It rattles like theres no tomorrow. I tried ordering a cat from partswarehouse but they rejected my request for a cat because the car is OB2. I wanted to know whats the difference between a ob1 and ob2 cat or could I pass smog with a 49 state legal cat. is there a big difference.

 

you need an obd2 cat to pass emissions,,,i dont know why but they want you to use a cat from 96 and up...the ecu must throw a code or somethin

 

yea I know it has to be an ob2 cat but I saw on EBAY that theres ob2 cats that aren't cali certified just 49 state certified. I dont get it though do they make CALI cats different for OB2 than other states. I was just going to get a MagnaFlow replacement thats EPA certified but it says not for CALI use. i dont get it.

 

I had the same problem when i got my catback i was lookin on ebay for a cheap cat but it said stuff like only off road use blah blah so i just sucked it up and bought a stock cat from napa for 140...140 was the cheapest out of autozone advanced auto napa and pepboys... OH and i have a 96 ex coupe as well