Failed smog a second time. Need your HELP

eeltam · Sep 8, 2013

1st test

		%c02	%02		hc			co			no
Test	rpm	meas	meas	max	ave	meas	max	ave	meas	max	ave	meas
15mph	1504	14.9	0.01	50	9	34	0.48	0.03	0.06	414	67	739
25mph	1071	15.0	0.0	34	6	43	0.45	0.03	0.06	701	62	315

2nd test

		%c02	%02		hc			co			no
Test	rpm	meas	meas	max	ave	meas	max	ave	meas	max	ave	meas
15mph	1534	14.30	0.11	50	9	73	0.48	0.03	0.19	414	67	495
25mph	1103	14.4	0.0	34	6	56	0.45	0.03	0.17	701	62	251

After the first test I replaced plugs, wires, ran sea foam, cleaned the egr and even added a little acetone to the gas. As you can see both hc readings went up and NOX came down.I had a friend check the cats with his laser thermometer and all four cats had a cooler reading at the output than the input. Now I believe this indicates bad cats. There is no way I can afford all four. I don't make much money. Two is gonna be very tough to do. is it possible to pass with just two good cats? Will the cheap universals suffice? Also, what exactly is the difference between obd1 and obdii cats.Any suggestions are welcome.Thx

Stanimal · Sep 8, 2013

iirc there is no difference between obd1 and obd2 cats themselves, just that on obd2 there is a extra o2 sensor located after the cats to tell the computer if the cats are working. i see no reason you would need 4 cats to pass, however i cant be certain unless you do 2 then try it. what year car do you have, and what engine are you running? what mods do you have done to the car? what state do you live in?

the5.ohh · Sep 8, 2013

Where do you live? Year of the car, motor?? Fix the issue or find a mom and pop shop that'll take $$ and pass you with no issues

eeltam · Sep 8, 2013

It's a '96 gt convertible. I have no mods, totally stock. I'm in The Republic of California. So one set of o2 sensors tell the computer the status of the cats yet I have no code coming up. Is that normal or is the o2 probably bad? Thanks for the replies btw.

Stanimal · Sep 9, 2013

your car should be obd2 and have 2 sets of sensors, one in front of the cats and one set behind the cats on each bank. if you dont have a check engine light, you shouldnt have a problem passing emissions. very odd scenario you are in.

eeltam · Sep 9, 2013

Yeah I don't get it. I'm thinking the o2's are bad too but the no code thing has me stumped. so was I accurate on testing the cats? the outlet should be hotter than the inlet, right?

DeepList · Sep 9, 2013

If your O2 sensors were messed up, I'm almost certain your idiot lamp would be on.

CC'S95GT · Sep 9, 2013

I don't know wy they're sniffing a OBD2 car. Here only OBD1 are sniffed and OBD2 are plug and go.
On topic, the front O2's actually control the fuel while the rear O2's make sure the fronts are working.
The front O2's could be going out. They do degrade over time. If you have over 100,000 miles and the origionals are still in then they should be replaced anyway.

You can't run just 2 cats because of the visual test. Your car came with 4 so ya gotts to have 4.

eeltam · Sep 9, 2013

OK I failed again. This time I went to a no pass no pay place. Wanted to try something I read in one of the forums and see what numbers came up. I added a gallon of acetone to five gallons of gas. The NOx numbers passed but the hc failed. The numbers came down considerably but none the less it still failed. I guess I will get two universal cats and see if that gets me thru. Any other ideas out there? Oh and still no codes being thrown.