Failed HC (PPM) Emissions

[vcrmonthly]

I took my ’93 Geo Metro for its annual safety & emissions testing a week ago so that I could get it re-registered. It passed the safety inspection, but failed the emissions testing. Both the HC (PPM) & the NO (PPM) failed. The CO (%) was well below the maximum allowed. The “Technician” told me that if I changed the EGR valve, the plugs and the plug wires, as well as getting it timed, it should pass next time. I followed his suggestions and took it back to be re-tested. This time, it passed the NO (PPM) part of the test by a slim margin, but it still failed the HC (PPM) portion of the test. On the HC test, it only showed a very slight improvement at 15 mph and exactly the same results at 25 mph. He then told me that he didn’t have any other suggestions for me, but it MUST pass or I can’t re-register it. I hope that someone in this forum can point me in the right direction to get this problem fixed. (Please….)
I did a search of this forum and was unable to find any previous posts that helped me.

[idmetro]

I'm no expert on emmisions but I'd be willing to bet that the reason you saw very little difference after changing your EGR valve was that it often isn't the valve that fails but the passages in the head that get plugged up making it look like the valve isn't working. Search the forum for EGR cleaning, try that and see what you get. I'm sure others will be able to address your situation based on the reading/response you have posted but I believe they too will recommend cleaning out the EGR passages. Also fresh oil can make a big difference in the results.

[vcrmonthly]

Followup:
I cleaned the passages that the EGR controls (after reading reply above). It helped the NO emissions some more, but didn't budge the HC emissions. I decided to "shotgun" it and replaced the PCV valve, O2 valve, Distributer cap and rotor. This brought my total parts to over $200, which is the amount you have to spend in Utah before getting a waiver. Bottom line: All the things I did improved all parts of the emmission tests, but it still failed the HC portion of the test. I got a waiver.

My dilemma is - next year when I re-register it, if it still doesn't pass I will again have to spend at least $200 on parts to qualify for a waiver. I would really like to get this problem taken care of so it will pass, because with the price of gas, I plan on running this little sucker for a long time.

[idmetro]

Here are a couple of other posts that will give you things to check. You could also check for backpressure as a measure of your catalytic converters health.

http://www.automotiveforums.com/vbul...ight=emissions

http://www.automotiveforums.com/vbul...ight=emissions

http://www.automotiveforums.com/vbul...ight=emissions

http://www.automotiveforums.com/vbul...ight=emissions

[mik13usa]

Most outfits recommend replacing the catalytic convertor after 10 years, they just don't last long after the geo's rings allow blowby or oil into the exhaust. I replaced my 94's last year and passed with flying colors.

[99Metro]

Is your car getting up to operating temperature? I stuck open thermostat will certainly give you the symptoms you described. I had the same problem. Changing the CAT made no difference. Some places will blame the TBI (if you have one), but replace it yourself - you will save A LOT of money.