Smog laws suck in california. This is the second time my car failed. Plus this is with a brand new cat. Here are the numbers. Everything is good except for my NO. After I got my 1st smog done i went to a shop(which i hardly do) and have them fix it. Then they told me it was my cat so i had them replace it. They boss said that if my car failed smog again then he will refund my money (which I paid 350). so to my luck it failed and i got a refund and a new cat. So now im stuck, any ideas?

1st smog.
rpm CO2 O2 HC CO NO
max 88 max.80
15 mph rpm1906 11.1 4.7 HC 84 CO .60 Nox max 835 measured 2264

25 mph rpm2053 11.5 4.4 HC 38 CO .24 Nox max 774 meas 771

2nd smog (new cat)

15 mph rpm1896 11.9 3.9 HC 88 CO .35 max..... Nox meas 2790

25 mph rpm2056 12.2 3.7 HC 24 CO .03 max..... Nox meas 261

Im planning to flush my radiator and use sea foam change spark plugs oil change etc. All I have done is intake headers and exhaust. Any help is really appreciated.


Modified by Blackhtch at 8:24 PM 12/7/2004


Modified by Blackhtch at 9:57 PM 12/7/2004


Modified by Blackhtch at 10:01 PM 12/7/2004

 

Bump

 

are you using high octane gas?

 

nope just 89

 

It might not do much but try using 87... is the motor high mileage?

 

134000 miles and a d16z6

 

try that stuff "guarantee to pass emissions".

 

Weird thing is that when i got my new cat all the numbers went down except for the 15 mph test.

 

yea sea foam might help u might have some carbon built up in the cambers cause denations in the cyn or hot spot that cause high nox yea the 15 mph has more of a load on the engine 50% load and 25 is like 25% load do u have the O2 readings on it?

 

yea i got that stuff lol. just bought it today with new oil and spark plugs

 

Hopefully it works we'll c tommorow when i smog it again. Can anyone explain why my nox is high at 15 mph test?

 

measured O2 is 3.9 at 25 mph and 3.7 at 25mph

 

dang man the 02 is high should be close to the co amount u are running lean also could be causing the high nox
dang man now i am trippin on my si hatch with 173000 on it and i have to go to a test only center bc i am goin there a smog class to get my certification. crap let me know how things go tmr

 

Among other things, high NOx could be from the fuel not combusting completely and making it's way out of the exhaust... Reasons to not use higher octane fuel than is recomended for your motor which for a z6 should be 85 - 87 unless you have upgraded internals.

 

so me running lean would cause high NOx?

 

nah nox is when the nitogen in the air and the oxygen are heat to above 2500 degrees and combine. if it was not complete combustion the CO would be high bc that is partialy burn fuel, and the nox would be lowwer bc the combustion temp would lowwer with more fuel in it
yes running lean cause high nox

 

I hear it helps if you drive your car around for 30 mins or so and don't shut it off even if your at the smog place. Don't know if it works cause I never tried it.

Good luck!

 

yes running it does help a lil bc the cat will be hot and when the cat is hot it burns the hc, co and nox only thing is dont let it idle bc the cat will cool down to much so like try to keep it at like 2000 rpms to keep it warm if u want to try that
oh y did u get a new cat from the reading it doesnt look like u needed one, did they test it?

 

my bad... I'm tired and drinking! Drink if you got 'em!

 

heh i dont know why they said i needed a new cat. But it seems like it brought down the 02 and CO levels in the second test. Even the 25 mph nox is lower

 

yea but HC is still up there and all and it didnt bring it donw by much if u would have needed one it would have brought it donw a lot, if u dont get that refund ask them for a work order with how they tested it to find out if it was bad. then post it and i will tell u if they dont u can turn them in and there shop can be shut down or fined
tell me how it goes tmr i got school early so i am outty hope u pass

 

god i love MN

 

I have another question. I was reading through archived posts and i saw this.
4drEFsaid "
NoX is caused by high combustion chamber temps.
What are the numbers you got for the other test readings?

If your cat was dead it would fail HC's.

You get high NoX from either having too much compression or from running lean. A lazy O2 is very common when you have high NoX. "

You guys think my o2 sensor could be malfunctioning thus causing my 15 mph nox to rise?

And my cars picking up a cel but only when its cold and idles low. When its warm the cell doesnt go on and I idle fine. You think this affected my nox at 15 mph test?

 

i pour some rubbing alcohol in mine (mixture with my gas) it passed fine

 

yea like i have been saying HIGH combustion temp causes NOx and the cel no bc its goes away but i would try to find out what the cel is. lazy o2 um.... not likely but can be do u know how to test it or have the tools too
also i forgot have u advanced the timing at all if so but it back to normal if u havent something that can help is retard the timing 2 degrees bc a z6 is 16 + or - 2, this will lower the temp some