Emissions questions

ASSISTANCE Stock Engine-Bay Components
1

Hi folks, let me introduce myself first. The name is Adam and I am new to the site. I just picked up a bone stock 135k miles 1993 Integra GS-R a few weeks ago. I did cap, rotor, wires, plugs, air filter, valve adjustment, and a fuel filter as soon as I got the car. I took it to get inspected, and it failed emissions for excessive HC.

Idle: 220ppm max Reading: 266ppm
High Idle: 220ppm max Reading: 244ppm

After seeing that, I replaced the O2 sensor with a Denso oem replacement. Disconnected the battery, reconnected it after 5 minutes, and drove it for about 50 miles. Went through inspection again, and I had nearly identical readings. I am now not sure where to go from here. All the other readings are within the proper limits. Its a sweet car that I would like to keep stock. Should I be looking at a catalytic converter next? Or is there something else I can do that would be easier to try first?

The car runs smooth and powerful throughout the RPM’s, no smoke, no oil consumption. Thanks in advance for the help. Also, this is NJ Inspections.

2

it probably is the catalytic converter. the way to test would be to measure temperatures before and after the cat. keep in mind that a catalytic converter only works when heated to a certain temperature. bringing it to that temp and keeping it there prior to testing is vital.

you could also retard timing a few degrees. that would lower hc enough to get it to pass. just remember to mark your distributor where it sits before adjusting. you may also need to tweak the idle screw a bit, as it will drop slightly.

3

you could be misfiring = HC is raw fuel - but then again you changed most of the ignition wire already too… hm… probably is cat going bad.