Arena993

I passed my emissions today. SAI pump removed. I always wondered what these numbers mean. I think they just tested CO2 or maybe all three criteria. Here they are measuring PPM.

HC - 0 (limit 220) - PASS
CO - 0.00 (limit 1.20) - PASS
CO2 - 14.20 (no limit listed) - PASS

Are these numbers good, bad etc...? Car runs like a champ, 100,865 miles. When I sold it 4 months ago I did an oil change and measured to 1/2 way up the dipstick. 1300 + miles later I added almost a 1/2 quart to get it back to 1/2 way. Any insight is appreciated.

Mike

Kika

you passed.... that is good.

Arena993

Kika,

I agree and happy for that. Just thought it may tell me something about the heath of the motor. Believe me the guy didn't even check the gas cap seal as he didn't know where it was. Just a way to get another $10.00 out of us.

Mike

e3photo

You seem a little doubtful. You might plan on a top end in the near future...... then you can sleep easily


Emerald

Kika

I am not an expert, but with low numbers, I would guess that means everything is being burned off and/or absorbed by the catalytic converter which is probably a sign of good health at least for the exhaust system.

I would think overall it is a great thing.

Arena993

You just want to build another motor. Hey I am glad it passed I just never knew what these numbers meant. I know it means I passed whatever standard the state set, but all I get is a piece of paper that says PASS and I give them $10.00. Car is strong and by my post above really doesn't use oil. Maybe I'll just won't stir the pot. Probably wouldn't understand what it meant anyway.

Mike

jhummel68

Absolutely! That piece of junk needs a top end. Man you are running on borrowed time!

Arena993

Always one in the crowd. That pile you call a car needs it worse than mine does. Rabbit Hash is calling my name.

Mike

Ed Burdell

Zero HC and CO? Sounds too good to be true. I think we're violating the 2nd Law of Thermodynamics here somehow. I wonder if their testing machine is wacked. Has anyone else received numbers this good?

Regardless - you passed. No takebacks if they change their mind!

Also regardless - your engine is probably just fine.

Arena993

I did look at the back of the test receipt and it states:

TEST PROCEDURES

For 1995 and Older Gasoline Engines:

1. Basic Idle Tail-pipe Test measures Hydrocarbon and Carbon Monoxide emissions

2. A visual inspection for Catalytic Convertor and Gas Cap

Again, I am happy with the test and the numbers the car produced. I know the car runs very strong and uses little oil. Does the 14.20 CO2 PPM measure anything going on in the motor like burning oil etc... What would a high or bad number be? More curious than concerned.

Mike

porschemikeandnancy

I passed my state of Washington emissions test earlier this month. My numbers (and the state limit) were as follows:
HC: cruise emissions 14, idle emissions 8, idle limit 220 (Pass)
CO: cruise emissions .03, Cruise limit: 1 (Pass), Idle emissions .01 idle limit 1.2 (Pass)
CO + CO2 (%) Cruise Limit 6, Cruise Result N/A (so why have a standard?), Idle Emissions 15.51, Idle Limit 6 Result (N/A) (again, why have a limit - my car appears to not be under the max limit)

The tester told me my car was amongst the lowest they tested that day.

But it cost $20, not $10. And they did remove my gas cap and test it.
Car is a '95 (OBD1) with 79k miles.

vincer77

Yes, the zeros for HC and CO looked pretty suspect, especially with the SAI out. My guess is that the analyzers were either not hooked up or not working. CO2 seems to be in line.

I just looked at my reports from TN and none of them ever reported emission readings. Wonder if that is a new requirement.

2Many Cars

My last 2 CA inspections (which are pretty tough) were zero HC and zero CO so I don't think your result is a fluke. The fact that the SAI has been removed shouldn't matter as IIRC it only runs at startup so with a hot engine it's not a factor in emissions, only to the OBD II in the later cars which periodically checks to see if it's working.

To answer the OP's question, in a perfect world the only combustion products your engine would produce is H2O and CO2. That never happens as you get some incomplete combustion which produces CO and HC (partially burned and unburned fuel) as well as a few other byproducts (like NO2). The FI system should keep the CO and HC numbers pretty low if it's working right as it meters in the correct air fuel mix quite efficently. The cat is just a catalyst (duh!) that completes the combustion of whatever HC and CO comes out of the combustion chambers. The main function of the SAI is to provide extra O2 to help complete combustion in the exhaust port and help get the cats hot enough to start working. If all is working right, and up to operating temp, the cats should clean up most of what's left. However, add a little oil blowby from bad valve guides or a bad fuel air mix due to a faulty MAF or the like and the numbers go to hell. Cats can also wear out but generally last a very long time unless they are stressed from too rich a mixture (which can make them overheat) or fuel additives that kill the catalyst. When all is right your emission numbers should be at or close to zero.

2Many Cars

Interesting data points using Arena's info above and my recent Smog Cert.:

HC allowable Max.

TN = 220
CA = 130 (at 2500 rpm, only 100 at idle)

CO allowable Max.

TN = 1.20
CA = 1.00

No surprise, CA is a lot tougher.

Leander

My CA smog cert from a year ago shows:

HC allowable max:
15 mph: 52 ppm (mine = 6 ppm)
25 mph: 36 ppm (mine = 6 ppm)

CO% allowable max:
0.49 (mine = 0.01)

They did check the fuel cap. Cost $80.