This may sound like a dumb question, but how do I make my car run more lean in order to pass the state emissions test. My Chilton's manual simply says not to mess with the mixture adjustments. I've looked everywhere but can't find diagrams of the carb to show me where the screws are. I know I have to turn it CW to make it more lean, but where are they?

BTW I have an 83 TA with a q-jet.
Thanks a lot.

 

theres no adjustment to new quadrajet carbs that i know of. but then again ive heard if you drill out the little caps that cover your adjusters its possible. the caps are in the very front of the carb under where the fuel line runs in. there should be 2 little silver caps in holes. ive never tried drilling them out and wouldnt suggest it.

 

How is your Oxygen sensor? Give is more INFO. What is the test procedure?
How are you failing? Hi HCs at idle only? The computer should be adjusting the carb's A/F mixture all the time in closed loop mode if you have a CC carb.

 

Its failing due to high CO. The limit is 0.97% and its putting out a little over 2.0%. The test is a 25 mph test on a treadmill. Its a 1983 trans am with the original carb. The HC passed fine, limit was 150's ppm and it was putting out about 100 ppm. They don't test for NOx. I've heard making it lean will reduce CO's and allow me to pass. I'm just wondering how to do this because I don't have any experience with carbs. Not sure where the mixture screws are. I know turning them a little bit CW should help.

The original 305 was replaced with a 350 which throws a check engine light code 41. I don't know how this affects it, but I know my mechanic ran it real lean and made it pass, and then tuned it back up. But I don't feel like paying him again if I can do it myself.

Any help would be appreciated.
Thanks a lot.

 

anyone know? All I need to know is where the screws are to make it run more lean. A picture would be awesome....

Thanks a lot

 

Base of the carb on the front. I've cut a few open in the past. They are idle screws--they only adjust the idle mixture. New O2 sensor, make sure it's running 200 degrees, cat is functional, ignition system is excellent, and the timing is perfect. Leaning it only helps when you are running rich already. If you go too lean, the engine will miss and emissions are even worse.

 

Nevermind people,

RXP got my 1983 trans am to pass. I simply dumped the whole bottle into my tank and then filled up with premium gas. Then I drove to the test facility, which was 20 min away. My CO dropped from 2.04% to 0.87%, therefore passing me. HC dropped from 105 ppm to 93.7 ppm.

Good product, not a gimmick.