Emissions problem...

[bonaturtle]

went in for my IL emissions test last week, and I failed. Car is completely stock, but the exhaust is Dansk I believe, but no holes in it or anything.

What could cause my hydrocarbon level to be at .30 (legal limit is .08) ????

Bad Catalytic Converter?

[scarceller]

Tell us more about the Hydrocarbon reading - ussually HC is in Parts Per Million PPM and good number is about 200PPM or less what is this value .30? %?

Also they gave you only one value? not one at idle and again at maybe 2500RPM?

A number that far off means lots of unburned fuel, I would really start looking at each cylinder to ensure you don't have a dead cyl. Easy test here is let the car idle, dissable Idle Stabilization Circuit (if you don't know howto do this just proceed to next step) no while car is at idle pull your electrical connector for each fuel injector one at a time (this means pull one then put it back before pulling the next) each cyl should cause a noticible drop in RPM and sound/vibration to the motor. Just go though each cyl and compare the results. If you find that one or more of your cyl don't drop the RPM or for that matter change the motor sound/vibration you have a possible miss fire in those.

Another thing that raises HC is burning oil - does your car burn oil? more than a quart every 500miles? These cars often suck oil through the valve guides and at idle you have lots of vacuum to suck oil in the intake valve. Exhaust valves, no matter how bad ussually don't bring oil into the burn cycle, but they do bring exhaust into the engine case.

So did you get only 1 HC number? Did they test the car on a dyno or static test? static tests are ussually at idle and at 2500RPM.

[bonaturtle]

wow, you're looking way to into this. I have a bad O2 sensor, and also not putting out the right mix.

I think you might have described the most expensive way to combat a hydrocarbon level.

What state are you in?

Nothing wrong with valves, injectors, and my car burns absolutely no oil. I can't wait to get this over with, seeing that IL will no longer require cars pre-96 to pass emissions any longer.

[Steve 82SC]

If you know someone with an exhaust gas analyzer, you could probably pass with a new O2 sensor. I was talking to someone a couple of years ago with a similar problem. He put in the new O2 sensor and leaned out the mixture (with the aid of an analyzer....he worked at a Chevy dealer). Then he took it for a 30 minute ride to heat everything up. Took it in, passed, and then reset the mixture.

Steve

[john walker's workshop]

unplug one injector.

[bonaturtle]

not sure how to do that, and does that really work? the shop that's fixing the O2 sensor has an analyzer, so I'll know beforehand whether I'll pass or not.

Steve82C, you downtown?

[scarceller]

Originally posted by bonaturtle
wow, you're looking way to into this. I have a bad O2 sensor, and also not putting out the right mix.

I think you might have described the most expensive way to combat a hydrocarbon level.

What state are you in?

Nothing wrong with valves, injectors, and my car burns absolutely no oil. I can't wait to get this over with, seeing that IL will no longer require cars pre-96 to pass emissions any longer.

I'm glad it was only an O2 sensor for you.

I am currently working on trying to get a 84 3.2L to pass HC at idle - levels here in RI are <200PPM at idle. RI only testes CO and HC at idle and 2500RPM (non loaded - no dyno). My car has NO cat. and I know that it may be near imposible to get this to pass, right now the CO is at .6% at idle and 2500RPM. HC is at 600PPM at idle and 150PPM at 2500RPM the limit is 200PPM at idle and 2500RPM.

So here goes, has anyone tried to pass a 3.2L with NO cat? I don't have the stock exhaust and the car is 22yrs old and insured as a classic, this turns out to be good news as I can qualify for emmisions exemption here in RI as long as I apply for the exemption (just paperwork and special visit to the states head emissions garage). I plan to do this route, but was just wondering if anyone has actual HC numbers on another 3.2 without a cat. Also, does a cat lower HC that much? (600PPM down below 200PPM)

Any comments on this would be helpfull.

Thanks

[JTL]

I went in with the bypass pipe in place and got a similar HC reading. Reinstalled the cat and she passed ok.

jt
-84 targa

[Tyson Schmidt]

Originally posted by scarceller
I'm glad it was only an O2 sensor for you.

I am currently working on trying to get a 84 3.2L to pass HC at idle - levels here in RI are <200PPM at idle. RI only testes CO and HC at idle and 2500RPM (non loaded - no dyno). My car has NO cat. and I know that it may be near imposible to get this to pass, right now the CO is at .6% at idle and 2500RPM. HC is at 600PPM at idle and 150PPM at 2500RPM the limit is 200PPM at idle and 2500RPM.

So here goes, has anyone tried to pass a 3.2L with NO cat? I don't have the stock exhaust and the car is 22yrs old and insured as a classic, this turns out to be good news as I can qualify for emmisions exemption here in RI as long as I apply for the exemption (just paperwork and special visit to the states head emissions garage). I plan to do this route, but was just wondering if anyone has actual HC numbers on another 3.2 without a cat. Also, does a cat lower HC that much? (600PPM down below 200PPM)

Any comments on this would be helpfull.

Thanks

Check the valve adjustment. A slightly tight valve can give the high HC reading at idle, that clears up at higher rpm, as yours does.

600ppm is too high even without a cat. That means something is wrong. Start with a valve adjustment, then an ignition system tune up. New cap/rotor/plugs, then start looking at injectors.

I assume you've already replaced the 02 sensor.

[scarceller]

Originally posted by JTL
I went in with the bypass pipe in place and got a similar HC reading. Reinstalled the cat and she passed ok.

jt
-84 targa

Do you recall your HC number at idle?