After a 3-week scare, I managed to get the 60 to pass emissions again. I tested it 3 weeks ago and failed due to high CO at idle. The limit is 1.20% and I had 1.21%. All the other numbers were within the specifications for passing.
I was worried about how things would turn out after two major repairs to the induction and smog systems since my last test. About a year and a half ago I replaced the manifold and other related gaskets due to deterioration of the old one and massive vacuum leaks preventing the truck from idling. Several of you also recall my air pump failure and replacement during the Colorado trip last summer.
I turned the idle mixture screw in half a turn, bumped the idle-speed back up to about 900 because it dropped when I adjusted the mixture and finally cleaned the K&N air filter. My idle HC ppm went from 25 to 14 and my CO went from 1.21 to 0.01. Logically, my O2 increased from nothing to a surplus of about 2% as well - but there's no specified level for that to pass or fail. I am a little confused because my CO at high speed (~2,500 rpm) went up with the second test. The HC stayed the same (8 ppm) but CO at speed went from 0.01 to 0.67% I didn't think adjusting the idle mixture screw would have any effect on the high speed numbers.
I was worried about how things would turn out after two major repairs to the induction and smog systems since my last test. About a year and a half ago I replaced the manifold and other related gaskets due to deterioration of the old one and massive vacuum leaks preventing the truck from idling. Several of you also recall my air pump failure and replacement during the Colorado trip last summer.
I turned the idle mixture screw in half a turn, bumped the idle-speed back up to about 900 because it dropped when I adjusted the mixture and finally cleaned the K&N air filter. My idle HC ppm went from 25 to 14 and my CO went from 1.21 to 0.01. Logically, my O2 increased from nothing to a surplus of about 2% as well - but there's no specified level for that to pass or fail. I am a little confused because my CO at high speed (~2,500 rpm) went up with the second test. The HC stayed the same (8 ppm) but CO at speed went from 0.01 to 0.67% I didn't think adjusting the idle mixture screw would have any effect on the high speed numbers.
