[BigEnos]

So, my Maxima *just* missed passing emissions last time. MD tests 3 things, NOx, CO, and HC. HC it passed but NOx and CO it was just out of spec on. I don't have the specific numbers here, but I could get them if it would be helpful. Any suggestions about what I can do to help the car pass? I am already planning to install a new O2 sensor (car probably needs it anyway), and the car had a new pre-cat and cat about 2 years ago. AFAIK they are still good. I've heard that a little alcohol in the gas tank will help. Any truth to it? Any other tricks like that? Like I said, it was close so just a little "bump" would probably do it.

TIA

This post has been edited by BigEnos: Mar 9 2006, 04:55 PM

[pknowles]

If you retard your ignition timing it will reduce NOx, but your HC's may start to come up. Alcohol is mainly for HC's, but will help Nox a little.

Where you sitting in line for a long time? If so you may need to go through at a non busy time so the cat can stay hot. I had an 88 Ford Ranger that I disabled the EGR on (got about 3 mpg better) and I ran the thing hard up and down the road around the emissions inpection station to get the cat real hot, then went through. Passed prefectly.

EGR helps with NOx is yours working?

[BigEnos]

If you retard your ignition timing it will reduce NOx, but your HC's may start to come up. Alcohol is mainly for HC's, but will help Nox a little.

Where you sitting in line for a long time? If so you may need to go through at a non busy time so the cat can stay hot. I had an 88 Ford Ranger that I disabled the EGR on (got about 3 mpg better) and I ran the thing hard up and down the road around the emissions inpection station to get the cat real hot, then went through. Passed prefectly.

EGR helps with NOx is yours working?

No idea if EGR is working. I wasn't in line very long, but I went through lane 1 and I've never passed when I've gone in that lane. I think I'll try a different lane next time.

The throttle body is a problem on this car, has idle issues that I think are related to it. From the graph, the car seems to have normal emissions when the car is moving, but they jump a little when the car is decelerating or sitting still. I don't want to mess with timing, I'm fairly sure the HC would jump too much. It wasn't that low.

I also have put new tires on it that seem to be about .5" larger, maybe this will help? ALso, I had old oil in it, but they say that only affects HC. Oil has been changed since.