Cant Pass CA Smog. Runnin too rich/ too lean?? Help!!

[Cardinal_5.0]

I just got my 89 GT (automatic) about a month ago. The guy I bought from said it would pass smog, so I take it in about 3 weeks ago, and the tech guy said that my emission levels were so high that the computer didnt even wanna run the test. Guy mustve felt bad for me, he just voided the test and didnt even charge me.

So one of the mechanics told me after that Im either running way too lean or way too rich. Said I should start with a basic tune up. My friend from back home said I should check my MAP, EGR, and air charge sensors, fuel pressure regulator, and the guy I bought the car from said it might need new cats, or a new smog pump.

I changed my oil yesterday, my air filter is good, and just ordered a new fuel filter today, should go in this wknd. Changed my cap & rotor and plugs a few days ago, and a couple plugs on the right side came out blackened, but white on the electrodes. not exactly sure what that means. anyone???

This is my first car, and Im excited to learn how to work on things myself. Any help on what I should do next is greatly appreciated

Thanks!

PS- Im a new member, and looking through the forums has helped me up to now, so I decided to join. Thanks for all the previous help!!!

 

[mavmavv]

Well, the biggest part of passing emissions is having cats (in good working order), your smog pump doesnt even affect things that much.

Where is Northern CA are you?

 

[strtrcr50]

To determine what the problem is, it would help to know the readings. High hydrocarbons(HC) usually means rich unless it is so lean the cylinder is not firing. High carbon monoxide (CO) usually means it is lean. High oxides of nitrogen (No2) means excessive combustion chamber temps and is usually caused by a malfunctioning egr valve. As stated by mav, good cats are a real plus and the factory 4 cat setup is pretty good for getting through emissions. Off the top of my head, I also believe there is a way to play around with the vaccuum going to the thermactor air diverter valve to make the smog pump pump all its air to the converters continiously. If I recall correctly, that will dilute down your exhaust with enough fresh air to usually pass. It has been a long time since I failed for emissions so I'm not sure about that one anymore.

 

[Cardinal_5.0]

I couldnt get the readings, according to the techs, they couldnt figure out how to get the test to run. I showed my old spark plugs to my friend yesterday, said I might be running lean tho, and Im not misfiring.

the guy that sold the car to me had a BBK X-pipe W/ High flow cats on when I bought the it, but he gave me the stock pipe. I threw it on the day i ran the test. Maybe the cats are bad.

 

[Cardinal_5.0]

mav, im in the bay area.

 

[mavmavv]

Id imagine the cats are bad. 5.0s dont have too tough of emissions requirements.

 

[HISSIN50]

The computer didnt want to run the test? Unless this is your friend, this sounds a little wonky to me.

As noted, having concrete numbers to go from would be helpful.

Good luck.

 

[Cardinal_5.0]

So I ended up just gettin a simple tune up (plugs, cap & rotor, oil change) and retested this week at a different place. I passed but I noticed my HC levels were a little high, 120ppm@15mph, (max is 121ppm), and 84ppm@25mph (max is 96ppm). CO levels were avg., and NO was a bit above average but not too high. CO2 reading was 11.5%@15mph and 25mph, and O2 readins were 5.1%@15mph and 4.9%@25mph.

Ive read high HC emissions can be caused by fuel that isnt burning right. With new plugs tho, what is it that I should look at??