Last week I failed inspection at our DMV. They failed me for emmissions the first time through, then in the recheck lane (I tried leaning out my carbs and going back through), they failed me for emmissions AND sound. Here's my results:

1st try:

HC (ppm): 636 @ idle, limit 600

CO %: 7.58 @ idle, limit 6%

For the first run, I was very nearly out of gas, so I went to the gas station, put in one gallon, and added a bottle of STP gas treatment (which I now realize was a bad move), then leaned out my carbs by one turn, went to get rechecked, and got these results:

HC (ppm): 734 @ idle, limit 600

CO %: 3.92 @ idle, limit 6%

sound: 96.7db @ 2500rpm, limit 96.5db .

So I filled the tank, added a bottle of emmissions stop, and I'm currently in the process of running through the tank completely before I try again. I'm hoping that the combination of the emmissions stop and leaning out the carbs will pass me. As for sound, I failed by 0.2db (which is bullpoopy if you ask me) so on the recheck when he tells me to run the engine at 2500rpm I'm going to go up to 2300 or so, hoping that it won't be as loud. I understand the reason for having laws against loud cars, but personally I feel that my car is so small that I need the sound to help people realize I am there, something like the train of thought that motorcyclists use.

Any thoughts?

A tune up would be the first thought.If thats good I have known people to put denatured alcohol into a low fuel tank.Don't use rubbing alcohol as it is mostly water.Check the % on the bottle.

Another thing you could try, would be to try a slightly hotter heat range of plugs to help burn the intake charge a little better.

If you have NGK BPR7ES in now, try a set of BPR6ES.

Might be the easiest and simplest solution, and one we often neglect to suggest too.....

i am so glad that we dont have any emmissions testing here. the only thing we have is red light cameras. i want to whip by in my z just to see what it can do.

Si|v3r72,

Hey that first try was pretty close. I got to agree with 2ManyZs instal hotter plugs I run BPR5ES in my L28 as an every day runner, this change should realy aid the clean burn with a re-tune on any average to good engine.

good luck

Steve:classic: