Hello Everyone,

I was reading a post on emissions and was hoping someone would have some input on what the issue might be. I own a 1985 Camaro with TPI and moved to Arizona and have been trying to pass the emissions tests for the Phoenix metro. I don't think they are squeezing too bad on the numbers, but the CO emissions have me baffled. Here are the last results from the tests yesterday...

HC 2.11 grams/mile - 2.40 allowable
CO 35.68 grams/mile - 20.00 allowable
NOx 2.81 grams/mile - 3.50 allowable

As you can see, I'm very high on the CO end. I'm running an almost stock engine, with the exception of 19lb Accel fuel injectors (as the General was asking way too much for Bosch injectors). All the stock emission equipment is still installed. I have yet to pull the spark plugs and look at them, but I know I need valve seals. I run synthetic oil too, which tends to find leaky seals easier than the 20W-50 oil I once used. I'm tempted to change the synthetic (10W-40) and go with standard 20W-50 and hope that it doesn't leak as much.

If anyone has any suggestion or ideas what might be the problem, that would be great.

Thank you!

 

Change your O2 sensor.

 

Replaced it after my second test, still the same result...

 

I am right outside your area,

I'm located in Central AZ more so than southern
also. Mesa/Tempe seems to have strict numbers
compared to Phoenix..

that surprises me quite a bit

As my CO allowable was 15.00grams/mile.

My car didn't have a CO problem, or else
I could be of more help. My CO numbers
were high my first pass at emissions, after
I changed the spark plugs they dropped by
a few grams.. (+ the cat was properly setup)

Usually the inspection guys give a sheet
of info, and on the back has categories of
where the car failed, and what could be the
cause..you could start there.

My HC problem was due to a overlap in cam,
resulting in unburnt fuel in the exhaust, But
the sheet also recommended a ignition tuneup
and new wires, ignition coil, and cap/rotor.

I'm no genius, what could cause a massive
amount of CO in the exhaust stream?? I was
told catalyct converters have almost nothing
to do with CO dilution, could it be a bad EGR
valve or component?

You look overly rich, way too rich..

 

It has me baffled too. At first, both NOx and CO were high. I knew that NOx was high so I finally installed a cooling fan setup from a forth gen Camaro and it keeps cool, not to mention the NOx is now WAY down.

I've looked at the info on the literature they gave me, some of the stuff is more of a shot in the dark. I'm not sure what to do with HC's being in check but yet CO high...most of the time it seems like the problems are a combination of HC and CO. I'll pull the plugs and see what they look like, all I can think of at the moment is either my fuel pressure regulator isn't working properly and I'm running rich or the slight burning of the synthetic is causing the CO to be high without impacting HC (since it's not petroleum based). I'm thinking that changing the oil to a petroleum based, heavy oil might tell a story on the next test. I supposed I should purchase a fuel pressure guage and eliminate that possible problem first.

 

I have a similiar CO problem. let me know what you find out...

 

pull your plugs,isn't high CO from lean run

 

CO is too rich.

 

I received my fuel pressure meter yesterday and I'm going to hook it up and watch the fuel pressure on the drive from work to home and see what's happening. If the fuel pressure regulator is working correctly, I'm really going to be confused!

 

your probably going to need to scan the ECM to see whats going on.
you know its running rich because of the high CO, but the ECM may think its lean & is adding fuel.
a few things that can cause the ECM to think its lean are, the AIR injection system may not be working properly, an exhaust leak before or near the the O2 sensor, temp sensor problems, & MAF problems.

 

My fuel pressure is good, plugs weren't great but I replaced them. AIR system is working properly, MAF seems to be working properly. Only part left that is questionable is the cataclismic converter, so I ordered one yesterday. If it passes, I'm putting the new one back in the box and using it once a year for emission testing. I'm going to use 20% alcohol to oxygenate the fuel a little more and that will help lower the CO a little bit.

Since I have a little oil consumption with this car, I read an article that oil emissions can reduce the effectiveness of the catalyst. Also, the AIR pump was disconnected for over three years on the original converter, so that's the only piece left that can be failing. I guess I'll have an answer by the end of this week when I have it tested.

 

Cataclysmic converter was gutted. Passed easily with a new one.

HC 0.87 (2.40 Max)
CO 12.14 (20.00 Max)
NOx 1.46 (3.50 Max)

So it goes, I never bothered to check it since everything else was connected. I have no clue why they didn't disconnect the AIR pump. Good for two years now!

Thanks everyone for the suggestions!