smog
11-29-12, 09:53 PM
#3
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tbh, the only way to truly verify a failed cat is to take pre cat readings and compare to tailpipe. if you don't know what's going in, you can't know how efficiently the cat is operating. there's actually a very simple equation for determining cat efficiency:
(HC in + HC out divided by HC in) + (CO in + CO out divided by CO in). take that number and divide by 2=cat efficiency. if the number is below 90%, cat is bad
that equation was for 4 stroke gas though. however, a cat should be a cat all the same. some will tell you that you can just measure temperature before and after the cat. that test is absolutely inconclusive.
problem is everyone always says just throw a cat at it. because it will, for the most part, get you a pass. most if the time the cat isn't the failure, but only the result of a failure. and what happens next time you need to get smogged? you're right back in the same situation.
how hot was the cat when you went in? did you drive it hard before pulling into the station? did you shut the car off in the lineup? because your hc and co numbers dropped right down in the higher speed, when the cat would have been hotter.
cats need to reach light off (roughly 500*f). if they don't, they will not convert emissions
firstly, what year and model?
(HC in + HC out divided by HC in) + (CO in + CO out divided by CO in). take that number and divide by 2=cat efficiency. if the number is below 90%, cat is bad
that equation was for 4 stroke gas though. however, a cat should be a cat all the same. some will tell you that you can just measure temperature before and after the cat. that test is absolutely inconclusive.
problem is everyone always says just throw a cat at it. because it will, for the most part, get you a pass. most if the time the cat isn't the failure, but only the result of a failure. and what happens next time you need to get smogged? you're right back in the same situation.
how hot was the cat when you went in? did you drive it hard before pulling into the station? did you shut the car off in the lineup? because your hc and co numbers dropped right down in the higher speed, when the cat would have been hotter.
cats need to reach light off (roughly 500*f). if they don't, they will not convert emissions
firstly, what year and model?
Last edited by welfare; 11-29-12 at 09:55 PM.
11-29-12, 10:56 PM
#4
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also, though my knowledge with these cars for the time being is very limited, i do know that these cars run rich. inherently. it is the nature of a rotary. it's why they run an air pump and multiple cats.
which brings me to another question; is the air pump operating correctly? are the lines free and clear? because the air pump is designed to help, ultimately, lower emissions at low rpm, when not enough heat is available for the catalyst to operate adequately, it would definitely be suspect
which brings me to another question; is the air pump operating correctly? are the lines free and clear? because the air pump is designed to help, ultimately, lower emissions at low rpm, when not enough heat is available for the catalyst to operate adequately, it would definitely be suspect
11-30-12, 10:33 AM
#5
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I noticed that it says modified for two of the visual tests. Do u have after market parts on it. Maybe a fuel pressure regulator. Or maybe u just have missing or in correct routing of some vacuum lines. Is it a turbo or na engine? can u take a pic of the whole print out so everything can be seen in the pic?
11-30-12, 10:53 AM
#6
Your high load test is way different from your almost-passing lower load test so I wouldn't count the cat out just yet. You'll need to verify your ACV solenoids and the vac lines connected to them are routed correctly. You want the ACV to supply "port air".
TPS needs to be set so it correctly feeds the ACV.
Or the cat didn't light off before the first test and did for the second. Was the cat warmed up thoroughtly before going to the test?
TPS needs to be set so it correctly feeds the ACV.
Or the cat didn't light off before the first test and did for the second. Was the cat warmed up thoroughtly before going to the test?
11-30-12, 10:51 PM
#7
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I failed on tbe visual i spection because the previous owner had two cats welded together for the main cat so i have 3 cat and they were saying your only allowed to have 2 cats.yes the air pump is functioning beside from the pill that i have from the apexi power intake thats about it.when i went in the smog shop i ddint drove the car enough to heat the cat up.the previous owner was able to pass the smog so im just waiting for my plates.i only needed the smog to get on naval base. But end up being a gross polluter.lol! got fed up having gross polluter from my smog made me install my mid and downpipe.hehe.ill put it back when its time to do another smog.
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12-01-12, 07:51 PM
#9
Speed Racer
Seems like it's the cat. I had a welded cat with racing beat header and I ended up swapping to an stock cat and the stock exhaust system while leaving the racing beat header on and passed.
12-03-12, 11:29 AM
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It really makes a big difference to thoroughly heat up the engine before you take it in.
I had another car that failed and I just drove it really hard before taking in it, and it passed.
So also try to take it somewhere it can be tested right away, and not have to wait in line.
I had another car that failed and I just drove it really hard before taking in it, and it passed.
So also try to take it somewhere it can be tested right away, and not have to wait in line.
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