Help me bring down the CO Levels in my exhaust...

[Mark B]

Hey guys,
I failed the sniffer a couple weeks ago. Its probably because I pulled off the AIR equipment on my car. Anyway, I was hoping you guys know some tricks to bring it down so that I can pass. I didnt fail by much. In addition to my mods below, I have:

-The timing advanced 8*
-The fuel pressure raised above the factory level
-A BRAND NEW High Flow Magnaflow cat.
-127,000miles
-I know my valve seals are going bad. On startup, I see a puff of white smoke come out the tail pipes. I am not getting in trouble for the smoke, cause its not visible, but mabey the small amount of oil that is getting into the engine while its running is hurting my emissions.

I was planning on droping the timing & fuel pressure back down to stock. Using a thicker engine oil for the test to stop any oil from getting into the combustion chamber. And maybe getting a new O2 Sensor. (I have to show a reciept for something when I bring it back to get tested) Any other tricks to help in passing?

I can bring it to a private testing center and "Pay a Fee" to get it to pass, but I would like to save a few $$ if possible.

[Joe 1320]

There is a product called "emissions test passer" or something to the like. You add the stuff to your fuel and run the car. It helps clean the cat and I have seen it work....... well enough to get you through the test. It has a money back guarantee as well. If it doesn't work well enough, at least you will get your dough back in the mail.

[ryan34]

There is a product called "emissions test passer" or something to the like. You add the stuff to your fuel and run the car. It helps clean the cat and I have seen it work....... well enough to get you through the test. It has a money back guarantee as well. If it doesn't work well enough, at least you will get your dough back in the mail.

Usually the guarantee is only valid if you have ALL the emissions equipment in working order. Kind of defies the point of using the stuff though, but i don't know how they can prove you don't have the emissions equipment.

[Jeff_in_Atl]

Hey guys,
I failed the sniffer a couple weeks ago. Its probably because I pulled off the AIR equipment on my car. Anyway, I was hoping you guys know some tricks to bring it down so that I can pass. I didnt fail by much. In addition to my mods below, I have:

-The timing advanced 8*
-The fuel pressure raised above the factory level
-A BRAND NEW High Flow Magnaflow cat.
-127,000miles
-I know my valve seals are going bad. On startup, I see a puff of white smoke come out the tail pipes. I am not getting in trouble for the smoke, cause its not visible, but mabey the small amount of oil that is getting into the engine while its running is hurting my emissions.

I was planning on droping the timing & fuel pressure back down to stock. Using a thicker engine oil for the test to stop any oil from getting into the combustion chamber. And maybe getting a new O2 Sensor. (I have to show a reciept for something when I bring it back to get tested) Any other tricks to help in passing?

I can bring it to a private testing center and "Pay a Fee" to get it to pass, but I would like to save a few $$ if possible.

The air pump system is only for cold start. It pumps air into the converter to heat it up faster.

How long did you drive the car before you took it to be tested. Most cars fail because the owner does not get it hot enough for the converter to convert. Just because the water temp is at operating temperture, doesn't meant the converter is hot.

White smoke is water. If the valve seals were bad, the smoke would be blue tinted.

[Benm109]

I would do what you suggested. Take the timing back down to the stock 0* and lower the fuel pressure. How long has it been since you've had a tune-up? And you said you may change your oxygen sensor, but how old is the one in your car?

[Injuneer]

The air pump system is only for cold start. It pumps air into the converter to heat it up faster.

He has a 3rd Gen. Its not the same as your 4th Gen.

The AIR pump runs all the time on the 3rd Gens. It has a "split bed" catalyst. The second bed needs the extra air (there is an AIR pipe on the cat, between the beds) to oxidze the CO to CO2 and the unburned HC to CO2 and H2O.

Try dropping the fuel pressure. High CO is a sign of runing rich. What did your HC's look like? Were they possibly also high, maybe just a little under the limit? That would indicate both running rich, and/or the absence of the AIR system.

[Mark B]

The car was warmed up plenty to get everything working right. I had just driven it about an hour (mostly highway.) I bought a Non-AIR cat hoping it wouldnt need the extra clean air because it doesnt have the "Split Bed." But I guess I was wrong. Here is what the entire readout sheet looked like.

Type______Standard__________Reading

NOx________879_______________78
HC_________117_______________75
CO%_______0.65______________0.89
CO2%________-_______________13.6

[Injuneer]

If you got a single-bed cat, you should be OK. You could try leaning it out. Leaning will elevate NOx, but you've got room to spare there. Leaning it will reduce CO and reduce HC's. Using fuel with methanol, ethanol, or "oxygenated" (MTBE, etc.) fuel will also provide extra O2 to combine with the CO and HC's.

[N20LT4Bird]

If you got a single-bed cat, you should be OK. You could try leaning it out. Leaning will elevate NOx, but you've got room to spare there. Leaning it will reduce CO and reduce HC's. Using fuel with methanol, ethanol, or "oxygenated" (MTBE, etc.) fuel will also provide extra O2 to combine with the CO and HC's.

I would be willing to bet your trouble is the elevated fuel pressure. Your NOx is only 78 PPM out of a possible 879 PPM......this is a sign that you've got a lot of fuel running through, keeping the combustion temps down. Like Injuneer said, you've got room to play with in the NOx dept., so lean it out to reduce the CO and Hyrdocarbons.......then crank it back up to where you like it after you get your sticker.