Emissions Test results: What exactly do they mean?

[R22tech]

Just had my car inspected, here are the results:

--------- reading -------- Allowable ----- result
HC-ppm ------5 ----------- 174 ------------ pass
CO-% --------0.00 -------- 1.12 ------------pass
NO-ppm -----214 ----------1258 ---------- pass
RPM ----------1710 --------1250-2500 -----pass
CO+CO2% ---14.9 --------6.0 min. -------pass

Besides passing, what do these figures tell me about my car? Just interested ...thanks

[pwd72s]

A 1985 car is over 15 years old. I suggest you call US Senator Tom Daschle and volunteer to have your car crushed. He, after all, knows best...

[Tyson Schmidt]

HC PPM= Hydrocarbons Parts Per million. These are unburned fuel particulates. Indicates misfire.
CO%= Carbon Monoxide Partially burned fuel. Result of overly rich mixture
NOx= Nitrides of Oxygen. Nitrogen linked to various number of Oxygen NO3,NO5, NO8 etc. hence the x. This is the result of extremely HOT combustion. High compression engines and Turbo chargers are the culprit. This is the biggest smog villain. This is what makes your eyes and nose burn.
RPM=Revolutions per Minute. This is how fast the engine is turning. Duh
CO+CO2= Carbon Monoxide plus Carbon Dioxide. This tells the tester whether or not the exhaust system has a hole in it big enough to give a false reading. (Drawing in clean outside air) Too low a number, and you fail, since the other readings would be falsely low.

The numbers you posted indicate that your car is well tuned and your emissions control systems are working. Good Boy!

[Superman]

Why, that's almost fresh air. Your car nearly makes fresh air, Reefer Man.

[ToyCollector]

That RPM reading isn't your idle speed I hope??

[Early_S_Man]

Funny story ... well, 'snipet,' from Autoweek back in the '70s about some of the airheads occupying Congress, and NTSA/DOT back in the days of Joan Claybrook ...

It seems that at the time of some hearings [about future HC & NOx standards] ... the ambient air NOx levels in downtown Washington, DC were at some figure 'X' ppm ... BUT, the proposal from Ms. Claybrook's staffers for future (circa 1985) tailpipe emissions was to be 0.33X ppm! They wanted to have the future 'fleet' cars be rolling air scrubbers for the Washington air! When chidded about the fact that the inlet air for those cars was dirtier than the proposed tailpipe emissions level ... all they could offer was that it 'seems like a reasonable proposal' ...

[R22tech]

Are you guys trying to tell me that my old car couldn't kill me if I stuck a hose in the tail pipe and started taking "bong hits" all day long from said hose?

I know it's a clean report, the test was done on a dyno in 2nd gear at approx. 1710 rpm. Interested to know if anything can be construed from the data. Also, now I can take off the cat. and see what she sounds like with 1) no cat or muffler 2) straight pipe and muffler 3) straight (by-pass) pipe and a set of ansa tips with resonators built in. Just stuff I have to mess around with and see the level of loudness I'm into on this car so I can choose the right muffler for me. Sometimes the info in this board is a little overwhelming, especially when preferrence comes into play.

[Tyson Schmidt]

You'd still eventually die, it would just take a few days for all the oxygen to be consumed. So you'd die of asphyxiation, not carbon monoxide poisoning.

Nothing can be accurately diagnosed after the Cat. You need to take the sample before the Cat. to really tell what the engine is doing. From those numbers though, you've got nothing to worry about. You'd need an O2 reading as well.