Car is a bone stock 95 Acura Integra 4 door LS. This car passed smog 2 yrs ago with flying colors. Had readjusted the valves and re-shoot the timming couple months after the smog test, drove it like that without replacing anything ever since, only oil change every 3-4K miles. Now this car has bout 250+K miles and it eats quite a bit of oil, but does not smoke, pings a little on hard acceleration( might be too advanced when it had the timming re-shoot) but still runs very good.

So recently before this new smog test, I had change the old spark plugs and found out that the tip of the spark tip had kinda melted in a way, not extremely just a bit slanted. It was somewhat getting poor gas mileage on small streets, but if in highway it still gets decent mileage around 350+miles full tank. So I replace the old spark plugs with new ngk platinum ones,(I know I didn't really need to use platinum spark plugs but got it for a good price).

So everything seemed gravy and I took it in for a smog test today, it pass the 25mph test but failed the 15mph test because Nox was high.

here were the results for 15mph test

please note: MAX=Maximum Allowable Emissions / AVE= Average Emission for passing vehicles / MEAS= Amount measured

CO2 MEAS 14.07
--------------------
O2 MEAS 0.16
--------------------
HC (PPM)
MAX 90
AVE 41
MEAS 59
--------------------
CO
MAX 0.54
AVE 0.12
MEAS 0.28
---------------------
NO (PPM)
MAX 711
AVE 150
MEAS 0780
---------------------
Results FAIL


Results for 25mph test

CO2 MEAS 14.09
--------------------
O2 MEAS 0.11
--------------------
HC (PPM)
MAX 43
AVE 25
MEAS 43
--------------------
CO
MAX 0.53
AVE 0.10
MEAS 0.22
---------------------
NO (PPM)
MAX 754
AVE 112
MEAS 0521
---------------------
Results PASS

I did some search online and found that Nox was due to having too much heat in the combustion chamber, causing a lean mixture perhaps. Kinda makes sense to me cause remember my old spark plug tip was melted in a way.
Im kinda comming to the conclusion that it could simply just be that my timming is a little too advanced, but i wanted to post this here to get second opinions on what i could or should check/replace before taking it back in, cause it kinda hurts to give away 42 dollar each time you fail lol.......

 

retard timming

 

anyone else?

 

Move to another state.

 

Retard timing to 14 degrees BTDC and you should be fine. What was timing at when you tested it?

 

Retard timing, check o2 sensor and CAT. Look at your AVE.

 

it jumps around from 16-18* as far as i can see, i redid the timming and now its right at 16* the red line or middle line, this is with a wire jumping the CEL plug, if i take out the wire from the CEL plug then it sits at 14*. this is correct right?

 

If you just want to cheat the test a little.



or



Both lower combustion temps, which reduces NOx emissions.

Retarding the timing can change the HC emissions, but that shouldn't be much of an issue for this car.

 

lol, have seen many people still fail with those stuff, but maybe because they are way over the limit on the smog test, it seems like my car just barely failed the nox by about 70 more, do you think your formulas you show me will work?

 

Retard your timing to 14 degrees, it will help bring down you NOX #'s, worked for me on 2 different cars.

 

I've had great success with the GTP stuff.

Brought HC down enough to get a foul running 88 Civic to just pass. Brought NOx down enough to pass on a Spitfire missing it's smog pump and EGR.

That's the extent of my personal experience though.

 

very close to doing that hhaahhah

 

do i just pour the whole bottle of g2p in my tank?

 

Seriously man, I feel your pain. Dealing with NY's emissions bullshit damn near drives me to violence, I can only imagine what you guys go though. If NY ever adopts SMOG testing (which wouldn't come as a surprise to anyone) I'm moving to Vermont.

Out of curiosity, why did you advance the timing in the first place?

 

i think im going to run only side exit headers for daily drivers once i leave cali, no cat or resinators just straight open headers lol........

anyhow, i was trying to set the timming at 16 but it jumps around alot so i think i set it advanced by acciendent.

 

I followed the directions on the bottle for my Civic. If my memory serves (and it's been a few years) you put the whole bottle into the tank, drive enough to burn half the tank, fill the tank back up, and go test.

It's mostly alcohol, which doesn't produce as much HC when it burns, which is what helps clean up the exhaust readings.

For the Spitfire, since the NOx was absurdly high (lacking the necessary smog equipment, raised compression, and a performance cam), I dumped one bottle in, drove for half a tank, dumped another bottle in, filled the tank, then had it tested. I should have done the correct thing and put a modern 3 stage cat on it, since the older 2 way ones don't break down NOx.

Alcohol burns cooler, so it reduces NOx.

That's why ISO Heet can be used, as it's a bottle of alcohol intended to help keep gas from freezing in super cold climates.

The car will run leaner with these additives in the gas. Don't push the car until you clear the tank (run to near empty, refill without additive).

 

okay fill tank up to full, pour the formula in, drive to half tank, refill tank without the formual and go test right? what would be the best gasoline to use (brand/octane) when testing for smog?

 

Brand shouldn't matter.

Don't use a higher octane than what the car is deigned for though.

Does the LS engine have an EGR? If so, cleaning out the carbon that builds up inside of it could help reduce NOx, if it's chocking flow now.

 

no egr, what about seafoam? can i use that to clean the carbon build up in the chamber? would that be ideal?

 

What makes you think you have carbon in the cylinders?

I don't trust seafoam and similar products. It just screams "snake oil" to me. Changing what is burning during the test itself seems like a more productive way to change emissions readings, to me at least.

 

Tagged for emissions info to be used in 2 weeks.

Thanks everyone! I'm definitely gonna pass.

Dm of mD