well not by much which is the good news,
40 km/h Idle
Limit Reading Limit Reading
HC ppm 79 14 200 12
CO% 0.44 0.00 1 0.01
NO ppm 0908 1108 <- FAIL

Everything else passed by far, this sucks!!! what would cause that to be so high and the rest to be very low??? bad gas? cat? all the tune up stuff on my car is good since i just got it back from the JDM B20A swap........advice need, what could be causing this?

 

1st guess is that your a tad lean.

Regards,
BigMoose

 

I think you should go ahead and replace the cat, or even better, just get a buddy to pass you.

 

how would i remedy a lean condition?
and cant fake emissions here.......fully computerised.......info is fed directly to the province........and would it be the cat? the rest of the values are so low (CO and HC) only the NO is high

 

If you have a friend, get him to put the sniffer in a different car and just print out the info for yours.

 

see the problem is i dont know anyone who could hook me up like that.........what about the fact since in japan they run higher octane and the timing is set up for that......im just running reg 87? would retarding the timing help? this reducing the NOx

 

retard the timing a few degrese.........should pass with flying colours then.....

 

I had the same prob, here's some ideas to help... first check the o2 sensors, and replace if dirty. I think you are too rich. Too lean would be less emissions and you would have passed. Another thing to try is blow your cat out on the highway for a bit and let the exhaust warm up real good, holds the nox down lower. You're last resort is a new cat. Hope this helps.

 

Good advice.

Again, most likely not. I just searched to see if I had my chemical kinetics plot of CO, THC, and NOx versus fuel air ratio, and it is not on this computer. But suffice it to say that a rich atmosphere is a reducing atmosphere. In a reducing atmosphere the reaction O2 + N2 -> NOx's is inhibited. NOX needs free oxygen to form. 'cayse in a reducing atmosphere those pesky Hydrogen atoms go right for the Oxygen..... Also the signature of lean mixtures is nil CO.......

You are right that his three way cat may be fubar'd or the O2 sensor.

The other thing that I was thinking about was that he talked of a swap. That could imply that the ECM is not set up right for transient fueling events, and if he went from a 1.8 to a 2 liter it would be swinging lean in transients, till the closed loop locked things up back at stoich.

Just a few other ideas. If you want to see the kinetics I can dig deeper, its probably on the net somewhere as it is reasonably widely known.

Found it when I got home.

It is a little higher right at stoich than I remembered. As others said, you are so close, drop a couple degress of timing and you will probably make it.

Regards,
BigMoose


[Modified by BigMoose, 9:54 PM 2/3/2003]

 

went from a 2.1 -> 2.0 using same ECU

 

run premium and retard the timing..both of those will help reduce the NOx.