also, i already timed my car at 10 degrees? so if i retard or advance it, wouldnt it end up not passing visual?

and would 1-3 degrees really change that number of NOX levels?

 

+1 on this... Clean the EGR but its most likely the cats. Why you ask? Well, its a different car (97 Prelude. My cousin's). He failed smog for high NOX. I researched it and everywhere it talks about cleaning the EGR. I took his EGR apart completely, cleaned it so clean like a whistle. He went back to get it smog and still failed. Changed the cat and boom, passed with flying colors. NOX is way way way way low than the average measurement

Good luck.

 

How long did you drive the car before being tested?

Couple things I would recommend doing.

-Make sure to remove and visually inspect every vacuum line, not just a quick scan. Double check the routing is correct with the diagram on the hood.

-Get rid of that crap HKS filter and install a stocker back on, just for the tests sake at least. I prefer AC Delco.

-As posted before, clean out that EGR. If it's in bad shape then also look into cleaning out the upper portion of the intake pipe where throttle body is located.

-Check for codes, don't expect the cell to be on for there to be codes present.

Good Luck

 

I just forked out some cash for my smog , good luck!

 

^LoL.... That definitely would be the cheap way to go instead of fixing the problem.

The cat itself is already about $200+ (for a good one). If a muffler shop says he can do it for less than that, prepare yourself to go back for a new cat after 2 years. This is exactly what happened to my cousin's prelude. His car failed the first time 2 years ago. Smog shop recommended a muffler shop for him to go to, got the cat replaced, passed the smog and its been 2 years and his car failed. Thats when I cleaned his EGR but then still failed... Went back to the same muffler shop, bought a much decent cat that the shop guaranteed to last for a while, took it back to to get it smogged and it passed. I think he spent about $300-400 for the new cat.

 

egr should be just fine cause i passed first time on last years smog and i cleaned the egr prior just in case.

i really doubt the HKS filter is gonna mess with my NOX levels. but just for the sake of the test ill put back a stock airbox back in along with a stock filter aka paper filter as you say.

i also just cleaned my throttle body 3-4 months ago, it was covered in oil.

ill barrow my friends cat and swap it over. ill check for leaks in my vacuum lines. ill check the timing for my car once more after all that.

thanks for all the inputs and advice!

 

I use to know a guy in LA that you would pay him and he would pass you.
If you would like I can look into that and let you know. Unless your not in SoCal.

 

I had that problem on my old dsm. I had a pipe made with 3 or 4 cats i dont remember, then i put a lil 100 octane in the tank (when I was on 1/4 tank) like a block away from the test center. What do ya know...my NOX was better than it was when it was new. NOX is usually a cat though, if you have obd2 hook it up to the comp and see what the o2 sensors read. It passed all the functionality tests just failed the sniffer! Once you pass register your car in a less populous area. I registered mine in EL Centro at my grandmas pad...NO SMOG out there!!

 

what was your measurements? im a smog tech

 

trust me, it's most likely not the cats. if it was the cats the HC and CO numbers would be through the roof as well as the NOx numbers. It's either a small vacuum leak or the EGR valve as mentioned before. Clean out the EGR first and see what comes out.

 

smog numbers are on page one

 

what he said. retard it a few degrees... no one is going to call you out on that.
Ive seen smog techs do it while the cars still on the rollers. old school style.

 

just came back from my re-test. after cleaning the egr, checking vacuum lines, retiming, and intake clean up, not much improvement.

gonna swap out the cat today hopefully and test again.

 

high NO in a toyota/lexus usually indicates a fuel mixture problem, normally wayyy too rich. swap the plugs, make sure the car is running nice and warm, GOOD gas, check the cap/rotors/wires, and most importantly use a multimeter and/or oscilliscope and check the O2 sensors, one or more is either bad, or dying.

 

will doo, thanks man!