I just got back from the inspection lanes, and i failed the idle emissions test badly. I've attached a copy of the readout sheet.


The car has a non CC Qjet and Distributer on performer intake with a crane 272H cam. The air/fuel guage is showing borderline rich condition at idle. I"m 99% sure this is the problem because at 2500 rpm, the guage is showing almost lean, and the readouts are well within the limits. So how can i lean it out at idle? What about those miracle additives that supposedly can get anything through emissions? I know about the alcohol thing but i'd like to avoid that if at all possible. I'm using 93 octane right now, would putting 87 in help any? I already knocked the timing back down, maybe i could go a little more?

Please help me out on this one..
Thanks.
Eric

 

That result looks real typical for a car that runs OK, but that's supposed to have a catalytic converter but doesn't or has one that's dysfunctional... you might want to start there.

 

The cat is a Catco High flow converter thats only about 7 months old. How can i check to see if it's bad? The headers don't glow red or anything. The exhuast is all welded so i'd like to try and avoid taking it apart unless it's absolutely nessesary.

Theres got to be a way i can lean the thing out at idle, i know it's rich right now, any ideas?

Eric

 

This is an easy fix.

1.) advance the timing about 5-6 degrees at least. Something like 15-20 degs btdc base.

2.) The idle mixture screws are in the front of the carb. They are recessed in there and you need a special too to adjust them. You can buy it at your local parts place. It is a flexible shaft with a screw driver looking handle. The handle is hollow and has several fittings inside it. Turn the screws in until the car stumbles and then turn them out a quarter of a turn. This is extreme lean condition, so don't drive it long this way.

Since they don't measure NOx the leaner and hotter you can run the more you'll drive down HC and CO. CO is a product of bad combustion and HC is a product of incomplete combustion. New plugs and wires cap and rotor would help out a lot too.

Does that say that your car idles at 95.2 decibles?

 

95.2 decibles was at 2500 rpms, which is actually wrong. THe real reading was 101.3, but the guy really liked ym car so he wrote down the legal limit instaed of the actual. AS for these screws im not sure what your talking about so i'm going to take pictures of my carb and maybe you can point them out to me.

Be back in a minute

Eric

 

these are my best guesses as to what you were talking about, am i right on this?

 

or these maybe?

Thanks for all the help so far...

 

The screws in the base plate are the ones. Not the style of carb I'm used to. Too many CC Q-jets for my taste.

 

Thanks man, i'll go see what i can do right now.

Eirc

 

yep that took care of it, off to the inspection lanes i go.......