I'm like 900% above NOx emissions on my smog failure certificate, how can I reduce NOx emissions?
My friend told me something like... an upper cylinder cleaning? I don't know exactly what that is, but he said they put some cleaner into your intake manifold or something like that.

What else could I do reduce NOx emissions?

 

I would search for it before you post. But until then I will ask the usual, Post the test results.

We don't need to see the average column.

Could be's Cat, O2 sensor, Timing, carbon build-up. At least these are the normal ones.

Your friend is correct upper intake cleaning. Seafoam (another search) will tell you how to perform this. However if you are 900% over it isn't gonna fix it. You have something else wrong.

HC MAX Measured
15=
25=

CO
15=
25=

Nox
15=
25=

02
15=
25=

Just copy and paste and fill in the numbers. It will help us help you. Also include the timing degree's too

 

HC MAX Measured
15=134
25=108

CO
15=0.82 MAX, 0.10 AVE, 0.69 MEAS
25=0.71 MAX, 0.09 AVE, 0.22 MEAS

Nox
15=847 MAX, 237 AVE, 1870 MEAS
25=786 MAX, 199 AVE, 811 MEAS

02
15=1.3
25=0.6

 

You have alot of 02 thru the exhaust which points to the cat. But if your 02 sensor is not doing what it is suppose to it will do basically the same thing. Unless you have an exhaust leak. Your numbers for 02 should be below 0.2, at 15 and 0.0 at 25.

Check your timing first.
And to go the cheapest route, go for a botttle of Seafoam and 02 sensor then give it another test. See if the smogger will do a simulated test on it. Not a pre-test. I call it an ASM diagnostic test I don't know what others call it.

If it still fails then the cat. That would be my plan of attack.

 

what model is your car??? if its a d15 its suppose to have an EGR

REMEMBER THAT

and if your car is a 1.5L, check to see if the egr ports are clogged, because during your 15, ur nox was high, and your 25 it dropped like a rock, so the cat obviously works

make sure your car is a 1.5, and if it is then check to see if your car stalls when vacuum (with a hand pump) is allipied to the EGR valve

and if its actually an si, check to see if the timing is too far advanced, because you also either failed for HC or was very borderlined

advanced timing causes incomplete combustion & high temp which form NOx

 

would the ecu have something to do with this problem i am in the same boat ?

 

It's a D16, 1.6L.
I've heard stories about the timing, is there a way to dumb it down? and what is this seafoam stuff?

 

dumb it down??? To check your timing you need a timing light.

Seafoam, Cleaner, 3 way's to apply Gas tank, oil, or manifold.
Cleans carbon build-up from backs of valves and tops of pistons.

There is directions on the can.

I apply it via the FPR vacuum line.

 

Which way is the best? Also, how many quarts of oil should I buy if I did an oil change?

 

on my ef 89 b16a, i passed after doing a basic tune-up. Changed the spark-plugs, checked timing, and adjusted the idle. And i live in California..haha. I guess the guy didn't care about visual. I barely passed the 2nd time though.....

 

Typically High Nox is created from excessive combustion chamber temperatures.

check your timing. make sure it isn't excessively retarded or advanced. do you have a chipped ECU? if so the timing maps are probably fairly aggressive.

i had the same issue with my B20. had Phearable chipped P28. couldn't pass Nox. adjusted timing, then couldn't pass Co2.
threw in my Hondata S300 with a stock B20 map and it passed easily. under 1/3 of the limit for all 3 test values.

 

For removing Carbon would be through the Vacuum line that goes to the FPR.

I use 5 oz. I put it in a coffee cup, then get a longer vacuum line and attach it to the fpr vacuum line nipple. Start the motor already warmed up and rev it to about 2500rpm. Then put the vacuum hose into the cup and suck a little at a time. When you almost finish the cup let the rpm's drop and stop the motor.

Let it sit for ten minutes or so and start it again and do the same thing.

Re-attach the vacuum line and go for a spirited drive(Caution, Don't speed) The last guy I told this to got a ticket for doing 90 on the hwy.

5 quarts of oil. You will have a little left over, don't forget the filter.

 

I just used the Seafoam stuff, the intake one. My car sounds and runs a lot better now... I was amazed. After I change my oil and flush my coolant I'm going to make an attempt at smogging it. I'll let all of you know how it goes! Thanks for your help so far :D

 

i have chipped p30 on a xsi and fine in all other stuff double on nox
so i am going to get a stock ecu