I know this comes up all the time. I read through many great posts about fixes to pass emissions tests, but didn't see one with my exact problem.
I've got pretty low numbers on all the different tests except for CO at 2500 RPM. I was able to fiddle with the idle mixture screw which made my CO at idle decrease a bit, but that managed to raise my CO at speed reading even more. I'm currently more then double the limit. Heres the numbers:
2500 RPM:
CO - 10.12 (5.0 limit)
HC - 180 (900 limit)
Idle:
CO - 3.66 (5.0 limit)
HC - 266 (900 limit)
Like I said I turned in the idle mixture a bit (3/4 turn), and also changed the air filter and did a little carb cleaning. This is on a stock '71. I do have a confirmed exhaust leak at the manifold, but I'm not sure if that affects this at all.
What's next? Any ideas why the idle numbers are good and the speed numbers are terrible?
Thanks for the help.
Tim
I've got pretty low numbers on all the different tests except for CO at 2500 RPM. I was able to fiddle with the idle mixture screw which made my CO at idle decrease a bit, but that managed to raise my CO at speed reading even more. I'm currently more then double the limit. Heres the numbers:
2500 RPM:
CO - 10.12 (5.0 limit)
HC - 180 (900 limit)
Idle:
CO - 3.66 (5.0 limit)
HC - 266 (900 limit)
Like I said I turned in the idle mixture a bit (3/4 turn), and also changed the air filter and did a little carb cleaning. This is on a stock '71. I do have a confirmed exhaust leak at the manifold, but I'm not sure if that affects this at all.
What's next? Any ideas why the idle numbers are good and the speed numbers are terrible?
Thanks for the help.
Tim