I have an '89 Integra LS. At low speeds (rpm 747) it emits 208 ppm of HC. At high speeds it is only 73 ppm. Other than a basic tuneup (new plugs, wires, cap, rotor, and air filter), what else will reduce the low speed emissions of HC? I must keep it below 220 for passing emission tests - too close for comfort - test coming up!

Thanks in advance.

 

I guess that there is not much expertise in this area. All have been quiet.

 

take away some fuel?

 

1) Is this a burning oil problem?

2) How do I burn more fuel??

 

1) I don't know the spark advance.

2) Is this a oil burning problem or does it simply need a fuel mixture adjustment?

3) How do I take away some fuel?

 

Do you have the measurements of the NOx and CO? It would help to see what's going on...

 

take away some octane by buying octane lowering fluid stuff at ur local auto store. just plug it in ur gas tank. make sure u have ur cat warmed up cuz the cat won't work unless it's hot. do a search. it's up.

 

In response to roadrunner:

Low Speed, rpm=0749

HC=211 (220 limit)
CO=.27 (1.20 limit)
CO2=13.6

High Speed, rpm=2269

HC=73 (220 limit)
CO=.50 (1.20 limit)
CO2=14.1

So, what does it look like the problem is? Physical burning oil or needs adjustment to some fuel/air regulation?

 

Any good advice or expertise out there?

 

Oh well.......

 

HC=211 (220 limit) ?
What is the problem?
A valve adjustment may lower your emissions somewhat. Your emissions don't look that bad. CO2 levels indicate that your engine is running fairly efficiently. A secondary ignition system tune-up (plug wires, distributor cap, rotor, spark plugs) should lower your HC as well. Your cat may be getting a little tired, they tend to do that when they get over 100k miles and over 10 years old.

 

The problem is comfort level. I am very close to the limit (above that limit - car cannot be driven here) and thus I would like to lower the level.

The car does have 140k miles on it and perhaps it is the cat getting tired.

So oil burning doesn't cause this problem?

 

HC's are raw fuel. High HC's are caused by a misfire. Misfire can be caused by several things: low compression, too rich or lean of a mixture, ignition misfire (fouled spark plug, bad wire, etc.), or an EGR valve that is diluting the mixture too much at lower rpm. In your case, your HC's are not that high. Your CO2 readings indicate that your engine is running efficiently, so I would guess that you have no major problems. If I was working on your car, I would adjust the valves and perform a secondary ignition system tune-up (spark plugs, distributor cap, and rotor, possibly ignition wires depending on the condition/age of the wires), and run a test to see where the emissions were. If the readings were still borderline, I would take a hard look at the catalytic converter. All of this is assuming that you don't have a check engine light.

 

Thank you very much for such a great informative response!!!!