Question for an 84 TA.

Engine is 350, CC Qjet, Headers, 3" catback, Cacto 4116 cat.

Emissions reading limits for Utah--
1981 and newer:

Carbon Monoxide: 1.2
Hydrocarbon: 220


My readings:
Carbon Monoxide:10
Hydrocarbons: 208
Nox - no reading, not required.

What would cause such a high CO2 reading?

 

From doing a little research it sounds like a combination of running rich and poor combustion. Or just an extreme of either of the two. Do you have an O2 sensor on the car? it being gunked up could cause that.

 

It's possible my tune is out, I moved from Sea Level up to Utah (4400ft elevation where I'm at). My O2 sensor is only 3 years old, I bought a heated one since this is my daily driver and I drive it year round. I wouldn't expect it to be bad however...it's a mechanical item so it's possible.

 

The more complete the combustion process, the higher the levels of CO2. CO2 is produced by the converter. Your instincts may be correct in that your mixture might be on the rich side. Lots of other factors play into this.

Is the engine stock? Emissions equipment still present and functioning?

Has the chip been tweeked?

Does your test report give an O2 measurement? Gives an indication of the combustion process/mixture (meaningless if the engine is equipped with an AIR pump).

Can you hook up a scan tool and read what the mixture is doing under the test conditions which the car failed?

What's weird is that your state fails for CO2 readings. Not even EPA **** CA fails for high CO2 readings (although it is measured).

 

1. Engine is not stock. 305 replaced with mild build 355. Only emissions still on the vehicle is the cat. I bought it in 2003 and it had no emissions equipment on it then save the cat. I would have to buy/find all of it. No emissions laws for my area of the state until this year (Jan 1) and now they've changed the laws and I need to get it checked so I can tag it.
2. Chip is factory (Computer controled Carb, not much to control really)
3. The shop didn't perform an o2 check or AF mixture reading.
4. As far as I know, the computer on these old CC Qjet cars doesn't give that reading and I don't have the $500+ for a good code reader tool that could make that reading anyway. I normally just use the paperclip method to pull codes if I need to (car isn't throwing any codes now). I'd need a wide-band AF meter to read the exhaust I think.

 

Fortunately you found a place that isn't a stickler on having all the emissions equipment in place. I have known quite a few people that failed a visual because of a lack of A.I.R pump and/or missing EGR.

At any rate, You are going to need to get the carb tuned(probably including re-jetting) for the altitude change.