Artyboy760

My 1994 honda accord failed smog becuase my (HC) was to high. It was in the 300's. I just installed a new CAT amd was wondering if thats gunna do the trick. Any suggestions?

MAD_MIKE

Depends on why the HC is high.

Running too rich, high HC.
Running too lean can cause a misfire, high HC.
EGR system not properly working, lean misfire, high HC.
Ingesting oil into the engine either from faulty PCV system or engine/seal wear, high HC.
Improperly adjusted valves not allowing enough lift or not allowing the valves to seat, high HC.
And so on.

Need more data to internet diagnose your probable issue.

If you are in Calif, post the 5 gas readout for both speeds tests.
Any other region, post whatever results you have been given from the previous test.

Artyboy760

At Idle (699rpm) - CO2 13.6 , O2 0.8 , HC 361 , CO 0.52

Artyboy760

At 2,500 rpm - CO2 13.8 , O2 0.8 , HC 77 , CO .64

celicool

When was the last time you clean out your EGR chamber? Your generation (same as mine) is notorious for clogging EGR chamber.