OK, so I failed smog pretty bad the first time around. I took the diagnostic to my mechanic. He said he usually looks for numbers 3 times the average to say the cat is bad (no CEL light on). The car is a '95 EX with new plugs, cap, rotor, no leaks, etc.

I bought a CA legal magnaflow cat, bolted it up, took the car directly to the test center. (I should have taken it out to the freeway and wailed on it first, but was in a rush).

Anyway, failed. I told the tech the deal, and he said cats typically have a coating. I should drive it for a couple days, and cruise back in. He said based on the numbers and everything, he wouldn't spend anymore money, just retest it... Anyone heard this before? Done the same thing and passed?

Test #1
HC: MAX AVE MEAS CO: MAX AVE MEAS NO: MAX AVE MEAS
92 48 143 .38 .11 .40 716 147 507
Test #2
HC: MAX AVE MEAS CO: MAX AVE MEAS NO: MAX AVE MEAS
92 48 121 .38 .11 .07 716 147 21

 

the cat needs to be hot to work properly so the hotter u can get it the better. drive it around for an 1hr before u go smog

 

What is the O2 and CO2 count?? No cats do not have a coating on them but they do need to reach 600 degrees to light off.

 

drive it hard for a while, keep that cat hot, and take it in when he isnt as busy so it can go straight on the test. a new cat is USUALLY a guaranteed pass. Ive never heard of catalytics having a coating on them though...

 

How did you clear your code when you replaced the cat? Usually I just pull the ECU fuse.... if you took your car directly to the smog facility after clearing the ECU, it was probably still in "learning" mode while it was being smog tested.

 

that's funny I drove about 4 miles on a cat and passed with flying colors.

the cat had a total of 4 miles on it.

If you have the ability to tune it you can pull ignition timing and set it to run 15-18:1 AF at idle, it will idle funny but its hardly making any emissions.

 

Are you 100% positive you dont have any internal oil leaks? Just because you have a new cat, and the car doesn't smoke, it can still have shabby emissions and fail smog.

 

Update: After putting 100 miles on the cat, it passed fine. The engine was borderline (burning oil), so this contributed. No other changes were made to make it pass.

 

My 1991 Accord failed the "NO" part of the emission test, other items were ok. I have the catalytic converter replaced. The mechanic told me to go straight to re-test the emission. But the emission test person told me to have at least 80 miles after a new catalytic converter before re-test. I listened to my mechanic and the new "NO" reading is worse than before the new catalytic converter. I'm waiting to put 100 miles on my car. I'll report how my emission test goes later.

 

After putting 100 miles on the new catalytic converter, I passed the emission test today. My NO reading for 25/25 test, the old number was 1592 (before driving 100 miles), it's 809 today and the allowed number is 945. For 50/15 test, my old reading was 1390 (before driving 100 miles), it's 949 today and the allowed number is 1045.

 

It won't pass next time. Guarantee u that. Fix that oil leak problem before you mess the cat up. Your only hiding the cause not fixing it. Has nothing to with warming up cat. Some days u burn more oil and some weather the readings comes out differently

 

QFT