92 nsx failed smog in california

[Mikexike]

Hey guys,

I just went and got my car smog and it failed with high NOx, i was reading the threads i found that it might be my o2 sensor or just bad cats but just wanted to ask and make sure i'm not missing anything.

here are my readings from the smog test.
rpm %Co2 %02 HC CO NO
meas meas max ave meas max ave meas max ave meas
15 mph-2564-13.9 0.6 114 27 29 0.73 0.09 0.02 785 255 1047
25 mph-2367-13.9 0.6 88 18 20 0.61 0.07 0.01 724 223 1081

thanks, any help would be appreciated.

 

[PHOEN$X]

I assume you read this thread.

 

[Daedalus]

Your O2 sensors are fine. CO and HC are close to average and well under max. High NOx could be cats, could be cooling system, could be EGR not working or not engaging due to test conditions.

 

[Mikexike]

I assume you read this thread.

yeah i've read this thread. looks like i need to take my egr valve out n check it out.

 

[Daedalus]

Cover the basics first. Make sure your cooling system isn't low on coolant and that your radiator looks good.

 

[Mikexike]

Cover the basics first. Make sure your cooling system isn't low on coolant and that your radiator looks good.

thanks, I'll call Shad at DA tomorrow and see what he thinks. didn't think about the cooling system.. i'll take a look into that.

 

[bngl3rt]

Cover the basics first. Make sure your cooling system isn't low on coolant and that your radiator looks good.

Out of curiosity, how does one decide if the radiator "looks good"? I suspect mine is underperforming for unrelated reasons.

 

[Daedalus]

Just a quick visual to make sure there aren't a lot of damaged fins due to rocks, careless techs, etc. On other cars it's also not uncommon to find leaves, cigarette butts, or even paper/plastic wedged between the radiator and AC condenser, blocking airflow.

 

[nis350]

Hey guys,

I just went and got my car smog and it failed with high NOx, i was reading the threads i found that it might be my o2 sensor or just bad cats but just wanted to ask and make sure i'm not missing anything.

here are my readings from the smog test.
rpm %Co2 %02 HC CO NO
meas meas max ave meas max ave meas max ave meas
15 mph-2564-13.9 0.6 114 27 29 0.73 0.09 0.02 785 255 1047
25 mph-2367-13.9 0.6 88 18 20 0.61 0.07 0.01 724 223 1081

thanks, any help would be appreciated.

Any mods on the car and mileage?

 

[Mikexike]

Any mods on the car and mileage?

Pride Exhaust. Comptec Intake... car has roughly 95k miles

 

[willabeest]

Pride Exhaust. Comptec Intake... car has roughly 95k miles

hey - i have a white/black NSX, i live in Folsom.
i always have problems with smog.
Shad always fixes it for me.
small world.
BTW aftermarket cats are legal now in CA and way cheaper than stock.:smile:

 

[Mikexike]

hey - i have a white/black NSX, i live in Folsom.
i always have problems with smog.
Shad always fixes it for me.
small world.
BTW aftermarket cats are legal now in CA and way cheaper than stock.:smile:

Funny thing! i just dropped off my NSX with Shad yesterday, is that your white nsx at his shop now?? i forgot who he told me it was but we should meet up once my car is fix. Its rare to see White NSX.

 

[liftnot]

hey - i have a white/black NSX,

BTW aftermarket cats are legal now in CA and way cheaper than stock.:smile:

Me too have blk & white:smile:
afaik, unless the cat is CARB'ed, its not legal
afaik, no AM cats are CARB'ed.
I had Random, Prospeed 400 and had a hard time passing EVEN if they are legal. One of the problems is they have much smaller surface area than OEM and SS dissipate heat much faster than cast. BAR is also lowing the number starting with early years
My smog tech saz he can't no longer heat up the cats anymore by law.
Correct me if I am wrong.

 

[nsx20014me]

My smog tech saz he can't no longer heat up the cats anymore by law.
Correct me if I am wrong.

This is true. My smog tech told me the same thing when I drove the car up to the rollers and then I started to rev up the engine. He told me to stop and said that was illegal now.

 

[ekhonda87]

I know a solution to your problem!!! Move to a better state...

 

[liftnot]

NO WAY!! Calif. is a crazy state to live but has too many positives that matters to me. You just have to figure your way around.
Snow is only good for one thing, hibernating is no fun, hockey is Canadian.....humidity and heat don't go together no matter how low the COL is.

 

[nis350]

This is true. My smog tech told me the same thing when I drove the car up to the rollers and then I started to rev up the engine. He told me to stop and said that was illegal now.

that's crazy... Lot of older cars are going to fail. Guess you just have to keep the engine running at high rpm while you wait for your turn.

 

[willabeest]

Funny thing! i just dropped off my NSX with Shad yesterday, is that your white nsx at his shop now?? i forgot who he told me it was but we should meet up once my car is fix. Its rare to see White NSX.

that was mine 1992. clutch hydraulic line broke.
DEC AM cats are CARB legal
i have white powder coated 1995 wheels. body lowered a little. previous owner did that.

 

[willabeest]

Me too have blk & white:smile:
afaik, unless the cat is CARB'ed, its not legal
afaik, no AM cats are CARB'ed.
I had Random, Prospeed 400 and had a hard time passing EVEN if they are legal. One of the problems is they have much smaller surface area than OEM and SS dissipate heat much faster than cast. BAR is also lowing the number starting with early years
My smog tech saz he can't no longer heat up the cats anymore by law.
Correct me if I am wrong.

DEC cats are CARB legal now. i go through smog in winter so really hard for me. maybe we should go to a test center mojave desert when 126 degrees air temperature. now that might get them hot!

 

[bngl3rt]

DEC cats are CARB legal now.

Ooh, where can I order up a set?

 

[willabeest]

Ooh, where can I order up a set?

i actually got mine from amazon.
you can go to the dec website and check them out.

 

[liftnot]

The DEC site is quite educational and well done. They don't show/say why their cats are better but by the looks of it, it uses honeycomb substrate just like many AF cats but they have a layer of heat shield wrap around the core of the cat to retain heat. Perhaps that is the trick similar to oem except in SS.
Let us know how it works out for you.....I am sure it will be very helpful to all of us in CA.

 

[nsxxtreme]

that's crazy... Lot of older cars are going to fail. Guess you just have to keep the engine running at high rpm while you wait for your turn.

Here in oregon I failed for a similiar thing. Mine has 50k miles on it. If you take it and drive it some more before taking it in it will pass with flying colors.
I dont think reving the engine is enough to get things warm enough.

 

[liftnot]

I dont think reving the engine is enough to get things warm enough.

100% true. With cast oem cats, this was the trick but with all the SS AF cats without heat shield, its nearly impossible. Next time I'll take a reading of my AF cats and see how close come to DEC suggested 1300+F in order for the chemical reaction to take place.

 

[willabeest]

The DEC site is quite educational and well done. They don't show/say why their cats are better but by the looks of it, it uses honeycomb substrate just like many AF cats but they have a layer of heat shield wrap around the core of the cat to retain heat. Perhaps that is the trick similar to oem except in SS.
Let us know how it works out for you.....I am sure it will be very helpful to all of us in CA.

let me put it this way. i passed, but not with flying colors.
my OEM cats were about the same. i would barely pass. not much difference, in other words.
i had a 1988 toyota landcruiser that was so clean and original it made me think the numbers were wrong. it had 180K on it.
CARB raises the bar, trying to get us to fail. some retired attorney should take them on. it does not seem right to me...