my 98 ex has I/H/E and it failed the 15 mph but passed the rest.
Any ideas what to do? I'm frigging pissed, I had to pay $50 for nothing
any help is appreciated.
Rich

 

Can you post the data sheets?

 

I was a little high on the HC i measured 70 and max is 64
CO was close, but passed...

 

could possibly be a bad o2 sensor or a bad catalytic converter. is your CEL on?

 

Yeah, could be a bad cat or O2 sensor. Definitely try to pull CEL trouble codes from the ECU. Also look for an exhaust leak, specifically a crack in the exhaust manifold.

 

no CEL...I called a couple mechanics one said bad cat other said no, that the headers were the problem.
I dunno what to do. grumble....

 

It still can be a bad o2 sensor even though it doesn't throw out a code. If its still the original one or you have a lot miles since it was last replaced, you may want to replace the sensor. If the sensor fairly new,I would replace the CAT, make sure you get a good CAT.OEM CAT's are not the same, it you just want it to pass then get a cheap one. Usually the smog station will retest or hook it up for free the second time around.

 

NOX or HC?

 

If the secondary O2 sensor is working, it will usually detect a bad cat and throw a CEL code. I'd focus on the primary O2 sensor and the possibility of a cracked exhaust manifold. You might also want to check the ignition timing with a timing gun.

 

so replaced the plugs (man they were black after 9K) and on the drive home threw a CEL.
so I'm thinkin it's gotta be the o2...
I prolly effed it up when I pulled it out of the stock header and put it in the megan
thanks all!