Alright, I have an 85 GS 12a that needs to pass emissions. My first test failed badly on everything except the gas cap! Got home and looked at the emissions crap and it was all there (as far as I could tell). Took a good look underneathand noticed that the air tube to the cat was not connected! Went back to emissions and FAILED only the HC. Here's what my test results looked like for both:

Test#1 Test#2

HC Cruise Limit: 180

Test Results: 477 222

HC Idle Limit: 220

Test Results: 1252 809

Is there any way to get this lower? Any help would be appreciated! Thanks.

 

So the difference between test 1 and test 2 is that you connected the tube from the air pump to the cat?

First, make sure your ACV is functioning and allowing air to go through the tube to the cat. Second, if that's in working order, you may need a new cat. If the tube was disconnected for a long time, the cat will be shot and need replacement.

Other things to look at are normal maintenance items. Make sure spark plugs, wires, other ignition parts are within spec.

 

try routeing the air pump to the cat, theres an article around someware.. I remember doing the same thing to pass emissions testing. Of couse the fall back is that you have to have a working cat, and everything has to be pluged up tight. Good Luck