R U ?
Get a new cat.
I haven't done my smog yet seems this is the planDid you happen to pass smog? Please reply and let everyone know how you did and let us know what you did to help pass.
What year miata? Judging by the 4xx nox at 25mph and 1000+ nox at 15. There is a good chance its not the cat. If it was 1000 25 and 1000 15, then there would be a better possibility it is the cat.So, after a spark plug/oil change, timing adjust, and fixing my purge valve that was malfunctioning, I had it tested again this morning. Except for this time I failed worse. Now it's a gross polluter. At 15mph, Instead of 1745 in the nox its above 2400 now. The HC is also failing now too. But everything passes at 25mph... WTF. I also drove the car for 2 hours to get to the place and had it running the entire time, so the cat was definitely hot enough.
I'm stumped but I'm guessing my next bet is to buy a new cat. I might just take it to a shop to be diagnosed, I'm tired of not knowing the real problem. I hate California's smog laws.
I've never had it replaced, but idk if it's the original one..It's usually the covnerter with high NOX. When was the last time it was replaced?
It's a '91. And that's what I'm thinking too, which is why I'm stumped.What year miata? Judging by the 4xx nox at 25mph and 1000+ nox at 15. There is a good chance its not the cat. If it was 1000 25 and 1000 15, then there would be a better possibility it is the cat.
You have an EGR valve. Check it to see if its working. Most likely its your EGR, o2 sensor or you have a vacuum leak somewhere. Check those before you get a cat.I've never had it replaced, but idk if it's the original one..
It's a '91. And that's what I'm thinking too, which is why I'm stumped.
That hasn't been implemented yet. It's still the old way of testing everything.Got a question. Recently I got smogged. The shop was star certified(the new gold shield) as well a test only. I got the tail pipe tested as well. What gives? I thought 2000 and up OBD2 would be only visual and computer?