FAILED Smog Test Emissions, High HC and NO at 15mph

[AKaption]

Hey guys,
I had a smog test yesterday and Failed at 15 mph with high HC (MAX 61; MEASURED: 146) and high NO (MAX: 467; MEASURED: 1069).

I Passed at 25mph, but barely, my HC MAX: 45 and MEASURED: 45


I also had my oil changed before the test, what I'm trying to do now is change out the fuel filter and clean the air filter, and I just put on some STP fuel injector cleaners.

Any other inputs?
Car is a 96 GSR with an AEM intake, DC headers, and WS2 exhaust.

Thank you!!!

[Lespaul59]

High CO2 IS FROM BAD o2 SENSORS WHICH YOU DON'T HAVE. hIGH NOx is from a bad egr valve or whatever regulates the cylinder gas from being too hot. Do you have an egr valve? Also it would mean the timing is off. And last too high Hc or hydro carbons means your catalytic convertor isn't getting hot enough to burn off the hydrocarbons or unburned fumes. That is most likely cause your cat is old and worn out. My 97 integra doesn't have an egr valve I don't think but not sure about the 96's.

[nfg177]

Run your car at a quarter tank and toss in 3 bottles of ISOHEET from autozone and you wll pass

[AKaption]

I also like to add that my NO numbers at 25mph is pretty good, MEASURED: 171; MAX; 754

Any other ideas?? I needa get this smogged and sold before I go back to school!
Thanks for all the input so far!!

[Craig92DA9]

To clarify high co2 numbers are an indicator of efficient combustion and would not indicate anything is wrong. A perfect combustion event would yield no by product other than heat, h2o and co2. What were your CO numbers? High CO is your indicator of incomplete combustion. High NOx is from combustion chamber temps in excess of 2500 degF. Does your integra have an EGR? If it does test it, it's jobs to prevent the formation of NOx by diluting the intake charge with exhaust gas. High HC indicates a rich running condition ( or a false lean) and high o2 indicates a lean ( or false rich) running condition. Some possible causes of high HC: engine not reaching operating temp, running rich, ignition misfire, mixture misfire, or compression fault misfire, leaky injector. Some possible causes of high NOx: inoperative EGR, engine running too hot, excessively lean mixture, excessive carbon build up in the combustion chamber, over advanced ignition timing, incorrect valve timing, ect. So for example you may have a rich running condition, the excessive amount of unburnt fuel could have caused your cat to overheat eliminating its ability to either oxidize HCand CO into H2O and CO2 and or it's ability to reduce NOx to nitrogen and oxygen, or your car could've running fine and the cat is just done. Emission analysts is not completely cut and dry and there are some datastream items that could help narrow it down like what your fuel trims are doing if you have access to a obd2 scan tool. I hope added more clarity than confusion, let me know if I should clarify something I said, sometimes I ramble and lose my point along the way.

[DC4KiD]

Can you scan your test results sheet? It would help us greatly in assisting you.

[AKaption]

Yes, here is a photo of the test results

Also, thanks Craig92DA9, those are very helpful information.

But how did I passed at 25 mph?
Thanks in advance!

[Craig92DA9]

I think it looks like you have some type of lean misfire, That would give you high combustion temps and poor fuel burn leaving unburnt HC and generating NOx.

[AKaption]

Just got it smogged again after changing the fuel filter, cleaning the intake, and putting fuel injector cleaners. Same results, and it's even worse than before. Here is a picture of the results.

I'll be getting a new cat tmr and smogged it again.

[DC4KiD]

You're not failing too badly.

How are your spark plugs? If they're new, what type/brand are they? What's the gap on the plugs? Distributor cap & rotor?

Fuel system/fuel injector cleaners are meant to be used completely, until the tank is empty. You'll then refuel, and go get the car smog-tested.

How old/new are your O2 sensor(s)?


Oh, and FYI, the catalytic converter is the LAST thing you'd want to replace (for any car!).

[AKaption]

I have the NGK spark plugs/wires. I got them and just had it installed. IDK about gapping.
NGK SPARK PLUG WIRES HE64 94-01 INTEGRA GSR DOHC VTEC B18C1 | eBay

Haven't replaced dist. cap/rotors, and I don't how old my O2 sensor is.

From looking at the test results, alot of people are saying it's my cat because the CO is also high, with high HC and high NOx as well.

[welltal89]

Cat failed me, Then again, it was a Magnaflow...But it's supposed to be CARB legal, Oh well I passed and it's back on

[modflip]

OP, I'm going through the same situation as you do but my NO readings were 3x than normal. So far I had replaced 2 O2 sensors and waiting for my cat converter to come..I also found out that my header pipe has a crack which might also be the case...good luck..

[vtakker]

High NO on an integra usually always means the cat. There is no EGR valve. My last smog I had an NO of 2600ppm! Then I got a new cat and the numbers were single digit. Aftermarket cats only last 30-50k. My last one lasted 35k :-/ You should pass with the new cat no problem. Just pass the test, then put whatever you want on your exhaust