Hey guys... I had some problems today with my scheduled emissons test.

Let me fill you guys in:

Setup:
Mugen Intake
Spoon header
Mugen twinloop
Stock ECU
Fuel pressure = 51psi
Timing at 16degrees
Dynomax cat

I ran the identical setup last year (minus Mugen intake) and had no problem passing. Here are my results:

Last year:
HC = 59ppm (86 limit)
CO = .04% (.48 limit)
NO = 79ppm (656 limit)

Today:
HC = 140ppm
CO = .62%
NO = 2136ppm

So it's plane to see that things have gotten much worse. Current thinking is that the catalytic converter is pooched but it hasen't thrown any engine codes yet. Does anyone here have any ideas?

Thanks!

 

My guess... lower fuel pressure.

Also make sure car has been warmed up for a while (long drive) (i'm sure you did this).

Check cat.

 

Stock FP = 47-54psi.

I did two tests (at two different drive clean centers) one at 48psi and one at 51psi, results for both were basicaly the same.

Car was plenty warmed up.

 

I'm guessing your cat is crapped out.

 

i would have to guess that the cat is probably dead.........

replace it and maybe even retard the timing another degree or two and it should pass......

 

Like stated before, your cat is most likely the reason.

I was considered a gross polluter in the state of california with a hi-flow cat. As soon as I put the stock cat on I passed with flying colors. Practically zeros across the board.

 

I knew you gutted your cat the moment you got 178whp at the dyno with your base pull. Shame on you Baby Nsx. I thought you were above all that kind of trickery.

JK

 

You and I are in the same boat. The catalytic converter is also my suspect...

On two tests, my HC were 99/45 and 67/60 of allowable 61/45 on the 15mph/25mph tests, respectively. All other values were safely in the pass range.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cruzersi00 &raquo;</TD></TR><TR><TD CLASS="quote">Like stated before, your cat is most likely the reason.

I was considered a gross polluter in the state of california with a hi-flow cat. As soon as I put the stock cat on I passed with flying colors. Practically zeros across the board.</TD></TR></TABLE>

Are you saying that you failed your emissions test with a cat which wasn't throwing a CEL? I am just surprised at the posiblity that my cat is blown while the ECU hasn't picked up on it yet... My very clean test from last year was with the same Hi-flow cat.

Edwin, when I replace my cat with a new one I'll have a perfect oportunity to punch the one that is on the car now... I'll use my new one for clean air days

 

I'm not exactly sure about the process or calibration necessary for the emission test, but for some reason the tech had to do it twice when I brought my car in (u're also allowed to 'passes' in PA), the first time which my car failed miserably, but the second time it passed with flying colours, not sure if it's possible but could it be the service centre?
This probably won't help as much given the numbers but clean the air filter, do an oil change and get the highest octane gas you can put in..

 

Do you by chance have cam gears? Reason i ask is, since the C5 has no egr system to speak of its possible to change the valve overlap with the gears there by effecting any exhaust gas recirculation or it's amount. just a thought.

My gut feeling?.....you cat is going south. You are showing elevated HC and CO levels as well as very high NOx. Remember to keep timing as close to stock as possible. High combustion chamber temps are a great NOx producer.

As far as the HC and CO goes.....have access to an infra red thermometer?
Quick test. Note : vehicle must be at normal operating temp.

With engine at 2,500 rpm, pull one spark plug wire and ground it. This will send air and fuel thru the cylinder. If your cat is up to snuff then it will continue to burn this additional fuel and start to heat up. So now, underneath the vehicle you take to measurements, one before the cat and one after. A healthy cat will show a noticeable increase in temp after the cat. If the temp after the cat is the same or cooler, its time to start shopping for a replacement.

Unfortunately, there is no test i know of to test a cats ability to process NOx, so that is why i mentioned timing and combustion temps. Good luck. Keep us updated.

Louie~ who hopes he passes next year.

 

I had that problem with the NO level in my Si, I was around 1600ppm (JDM header, 2.5" cat, ctr cams, vafc, etc). Added ~10% more fuel via the VAFC in the test rpm range and my ppm dropped to I believe 120ppm (something ridiculously low), HC and CO levels dropped as well. Hope that helps.

Brian

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Brian*Blue95M3 &raquo;</TD></TR><TR><TD CLASS="quote">I had that problem with the NO level in my Si, I was around 1600ppm (JDM header, 2.5" cat, ctr cams, vafc, etc). Added ~10% more fuel via the VAFC in the test rpm range and my ppm dropped to I believe 120ppm (something ridiculously low), HC and CO levels dropped as well. Hope that helps.

Brian</TD></TR></TABLE>

Very interesting... Could it be possible that the Mugen intake leaned out the mixture enough to have this much effect? That was the only change between the two tests.

 

If you want to pass, use the old tricks of the trade, swap out to a stock cat, and retard timing

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by canuck-mx6 &raquo;</TD></TR><TR><TD CLASS="quote">If you want to pass, use the old tricks of the trade, swap out to a stock cat, and retard timing</TD></TR></TABLE>

Old cat wont fit anymore New hi-flow will be installed tomorrow... hopefully that will fix things.

 

Yes. My Hi-flow cat doesn't throw a CEL with either my stock nor OBD I ECU.

It is very possible that within a years time that an aftermarket Hi-Flow cat will lose it's capability. Have an exhaust shop customize your stock cat to make it fit.

 

lil' on the rich side? lower the fuel pressure

 

I would say the cat is bad. If you were making that kind of power, you were probably running rich to be safe and usually a very rich mixture will kill most cats very soon. My cat exploded shortly after some rich tuning I did to make sure I did blow the motor. I made 181 hp with the old setup before the new cams and destroyed the cat in about a month. Now I just run a test pipe until I can get some tuning by SGT. Hopefully that will be soon when I move closer....

 

I'm going to go with most people here and say it's the cat...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mamaboy &raquo;</TD></TR><TR><TD CLASS="quote">lil' on the rich side? lower the fuel pressure</TD></TR></TABLE>

High NO levels generally indicate a lean condition

Brian

 

Well my new cat will be installed this afternoon... I will keep you guys posted on the results!

I think my running a borrowed Mugen ECU for the expo killed my cat. We all now how rich that thing likes to run.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Brian*Blue95M3 &raquo;</TD></TR><TR><TD CLASS="quote">I had that problem with the NO level in my Si, I was around 1600ppm (JDM header, 2.5" cat, ctr cams, vafc, etc). Added ~10% more fuel via the VAFC in the test rpm range and my ppm dropped to I believe 120ppm (something ridiculously low), HC and CO levels dropped as well. Hope that helps.

Brian</TD></TR></TABLE>

nvm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BABY NSX &raquo;</TD></TR><TR><TD CLASS="quote">Are you saying that you failed your emissions test with a cat which wasn't throwing a CEL? I am just surprised at the posiblity that my cat is blown while the ECU hasn't picked up on it yet... My very clean test from last year was with the same Hi-flow cat.

Edwin, when I replace my cat with a new one I'll have a perfect oportunity to punch the one that is on the car now... I'll use my new one for clean air days </TD></TR></TABLE>

The tolerance for the HC per Helms is out of spec with CA emissions - go figure. Therefore, I imagine one wouldn't get the "Catalytic Efficiency Below Threshold" code unless one was significantly out of range in the 02 sensors' readings, relative to emissions. Obviously, much more than 60-odd ppm in terms of HC.

 

I was speaking with John at HyTech about replacement High-Flow catalytic converters and since there was a CARB testing labratory next door we had a very good outlet to ask questions on. We were told that the non-OEM cats were not designed for the OEM market, and did not have the 100,000 mile warranty, they will typically allow a car to pass the emmissions testing, but will fail to properly function within the next 20,000 miles, or so(this was per the CARB testing labratory).

From there HyTech went on a search for a 100,000 mile catalytic converter to be used in his exhaust system...unfortunately he's had a few issues dealing with the company that makes the "bricks" and the company in Europe that assembles them into finished catalytic converters, hence the reason that he's still waiting on CARB approval on his exhaust system .

Just thought that I'd pass the information along,

Austin

 

my high flow cat threw a cel about 20 minutes after I installed it....

Why do some high flow cats trip a cel 67 and some dont?