Car: 92 Civic Vx

Motor: 95 B18C1, DC 4-1 header, ITR cat-back with muffler

New cap, rotor, plugs, magaflow cat., new but might be bad o2 NTK sensor

Well, see the results to further analysis.

 

.............

 

If you have a new cat, o2 sensor, tune up and no cel's you should pass.... Did you drive the car hard for about 30 mins. and go straight to the test center? Leave it running and don't let it cool after railing on it. Is it a factory replacement cat or a high flow?

 

Replacement. Yeah, I railed it. I keep my revs up. But they do a visual inspection. So the car will be off maybe 5+ minutes. Dumb ref. Thinking about getting a OEM CAT. People say to use denature and 87 octane?

 

I should explain that suggestion. If you're uncomfortable with 87, try 89 or even 91 octane gas. Keep in mind that the higher the octane gasoline-> higher levels of HC.

Denatured alcohol is an oxygenator when burned -- same as MTBE or any of the fuel additives. During combustion, it will introduce more oxygen to the chemical reaction. Now that there are more oxygen in the mix, left over HC in the combustion chamber will be ignited-> thus lowering your HC levels.

In a nut shell:

1. Gasoline burns first (lower octane)
2. Alcohol starts to burn
3. Chemical reaction of burning Denatured Alcohol introduces more oxygen
4. With more oxygen, left over HCs will start to burn.

As for mixture, you can do 1 quart denatured alcohol to 2 gallons of gasoline. Once you're done with the sniffer test, add in more gasoline. Denatured Alcohol doesn't play very nice with rubber. Good luck!

 

.......I will consider with that option but not right now. Should I change out the header for stock? Retard timing a bit 15, 14?

 

Dont retard the timing. That will richen up the mixture and raise HC. HC is basically unburnt fuel. Maybe advance it by 1 or 2. You have a leway of 3degrees. Also, are you using the correct spark plugs for this engine? Looks like the cat is doing its job and thats keeping the nox down as well as the co.

 

ngk bk6re

I was thinking about doing sea foam. The guy I got the motor from said it has around 115k miles. Should I replace the pcv? Bad ignition? Get a new dizzy perhaps? All I have changed since I got the motor is oil, plugs and wires. Everything else is untouched.

 

Im sure your dizzy is fine. Also, I have passed multiple times with a header no problem. I would never recommend sea foam. Some people like it but I personally have had very bad results with it and have seen others with the same problems from using it.

 

I'm not passing. I'm putting back the stock header. People at Honda uses it so it's fine.

 

Will PCV V lower HC?

 

I had the same problem with my swap, the HC was too high, even with my catalytic converter newly replaced, I replaced the O2 sensor and the HC dropped dramatically,,, smog passed! ***Note replace the O2 sensor with a good brand, dont just get the cheapest one available***

 

This o2 is just a little over 100 miles and it's the NTK/NGK brand. What's a "good" brand?

 

Switched out to my old dizzy with my friends' OBD2 LS O2 sensor. NO reads 376 and 43.

The very next day, same dizzy, friends' "good" Bosch O2 sensor.

 

....I need my tags........

 

Did you ever figure out how to lower your HC?

 

On your first test before you used your friends crappy o2 sensor and his dizzy you were running slightly rich. What ecu are you running? and bosch o2 sensors are junk. Dont use them.