No Cat, No Air pump, Passed Emission Test!

[Jadams1]

About two years ago I removed my Air Pump and injection rail setup a few months after I got my SC inspected. On Saturday, I went to the Sunoco station I used the last time and had the two idle speed emission test done and failed on %CO at idle. My car is too low to put on the dyno so they did the idle test. Here were the readings.

READING/ LIMIT
HC PPM IDLE 130 / 300 pass
HC PPM 2500 RPM 37 / 300 pass
CO % IDLE 3.63 / 2.50 fail
CO % 2500 RPM 1.56 / 2.50 pass

I was thinking, $hit, I have to put that damn air pump back on! I did a little search on the BBS and follwed the advice listed in a few post. I retarded the timing to 5 BTDC at idle (I was 8 BTDC) and leaned out the CIS fuel mixture by turning the 3mm screw CCW 1/2 turn and opened the air mixture screw to get the idle back up as high as possible but below 1,200 rpms. 1,200 rpms' is the max idle speed allowed for the test. I used a portable gas analyzer that we use at work for confined space entries and monitored the CO throughout the process. I played with the fuel mixture until I got the lowest reading but the biggest reduction in CO came from opening the air mixture screw (dillution is a great thing). At those settings the car really idled like crap and backfired once and a while out the exhaust. I went back this morning for a re-test and passed with flying colors, here are the new numbers. The machine was re-calibrated just before I was tested.

READING / LIMIT
HC PPM IDLE 186 / 300 pass
HC PPM 2500 RPM 23 / 300 pass
CO % IDLE 0.09 / 2.50 pass
CO % 2500 RPM 0.06 / 2.50 pass

So without a CAT and without an air pump I passed the RI Emission test! As soon as I pulled the car out of the garage bay I re-set the fuel mixture back were it was and turned the air mixture screw in to get the idle back down to 950 rpms.

In RI, if a car is 25 years or older, the car still requires the emission test be done but if you fail, you still get a sticker and don't have to do anything else. So the next time I'm due for a test, it won't matter.