Originally Posted by Duke2.6

Yep! That should do it. I figured this out over 15 years ago and documented all the testing I did.

http://www.peachparts.com/shopforum/tech-help/117048-successful-ca-asm-emission-test-ke-fuel-system.html

Failing the whole test because HC was 1 ppm over the cutpoint is a crock. The problem is likely catalyst aging. Go to a place where you can get on the dyno ASAP, don't shut off the engine. Open the windows and turn the AC to max to put some load on the engine. Retarding the spark advance map by shorting the R16/1 resistor and blocking vacuum to the EZL will significantly retard the spark advance map, which increases EGT that will get the catalyst hotter early in the test. This will reduce HC by 20 to 30 percent, and dramatically reduce NOx due to lower peak combustion temperature from the retarded spark advance.

You should also see a reduction in O2. If it gets to zero it means the catalyst is enabling essentially all possible oxidation and reduction reactions.

I made a shorting plug with a short piece of wire stripped on both and bent into a "U", and used a short piece of 1/8" vacuum tubing that I plugged with a slug of silicone sealer to temporarily replace the short piece of molded vacuum tubing from the inlet manifold nipple to the clear nylon tubing.

Let us know how the retest turns out.

Duke