Failed emissions test

[Silver86LX]

Well like the titles says, my car failed it's emissions test. It's an 89 Accord LX (carbed). Here are the numbers:

@1996 rpm
HC ppm Limit:79 Result: 9 (pass)
CO% Limit: 0.44 Result: 0.00 (pass)
NO ppm Limit: 908 Result: 1662 (fail)

Curb Idle (896 rpm)
HC ppm Limit:200 Result: 54 (pass)
CO% Limit: 1.00 Result: 0.00 (pass)
NO ppm N/A

So far I've chaged the PCV valve, air filter, plugs, and wires. The cap and rotor appear to be in good shape (that's why I haven't changed them yet). Any suggestions as to why my NO ppm is too high??

[XxDark_AccordxX]

that sucks when you fail emissions. then u hafta go thru the whole process all over again. what a pain

[Cyric_accord]

What condition is your EGR Canister/Valve in and your Cat Converter?

[Andrew]

Dump a litre of methol hydrate into your tank and then fill it up with the highest octane fuel you can get.

[Mike's89AccordLX]

Hey I just learned this in school today. B/c we're learning all of the emissions stuff and we learned tips on how to pass an emissions test.

First off Honda Cats. are designed to cool off rather fast.

So what you need to do is when you're waiting in line don't let it idle, keep the rpms up around 2k to 3k rpms so the cat has a chance to warm up b/c the cats cool down at idle and that can raise your numbers. I tested my 94 Prelude Si today with an OTC Gas Analiser and it failed. I was like this car is in great shape and runs good. My instructor told me to hold the gas at 2k rpms and the number just started dropping fast.

Did they give you any numbers on how much O2 was in your exhaust? This machine tested: CO2, CO, HC, NOX (Oxides of Nitrogen), and O2. And we had the live data feed in bar graph mode.

-Mike

[Silver86LX]

I just bought the car and had a good look at the exhaust system last week when I was doing an oil change. Everything from the cat back looks like it's in great shape. I was just talking to a friend of mine and he told me it might be my timing that's a little off. Would that cause the NO ppm to be so high?

[Mike's89AccordLX]

No it shouldn't have anything to do with that really. Maybe your cat is just not working properly. A quick way you can test a cat if you just have a Temp Gun is checking the inlet temp and outlet temp. The outlet temp should be 50-100 degrees hotter than the inlet on a properly working cat.

[Silver86LX]

Thanks I'll check my catalytic converter to see if it's working. But I did a search and found a thread where someone had the same problem I did (high NO ppm), and it turned out the timing was the reason why his car failed.

[unc25]

Yep yep...We adjusted the timing and it passed with flying colors!!!
Not sure how much but we did lower it..Thats about all I can tell you
From what I read, No-ppm is the fuel that doesnt get burned up..Too much is a bad thing..But then again I could be wrong....
Double check your timing though, its pretty cheap or free to do and it may just pass!!!

[Silver86LX]

I think it just might be my timing because my car idles a bit rough, and my fuel mileage hasn't been the greatest (about 260 mi/tank 75% city driving).

[Silver86LX]

Well this weekend I adjusted the timing (it was retarded), changed the cap and rotor (just to be safe) and swaped in my thermostatic air cleaner from my '86 (that one appeared to be in better shape). I'm going have my car re-tested on Monday and I'll see what happens.

[smufguy]

For high NO there is only two reasons, Bad egr or ur car running lean which means the NOx is not killed in full and the cat needs a little bit more of a rich exhaust gas to work in its full potential. So yeah, A tune up or timing adjustment would work. Damn i am late to this thread . but anyway good luck

[grsmnky33]

Like Mike said, get your car as hot as possible then take it to the smog shop FAST and have them run the test as soon as you get there......... Living here in CA, SMOG TESTS SUCK!!!!!!! My car still passes the test with the original cat in place (206k miles)....... from the looks of your NO readings, check your EGR valve, probably sticking open when it's hot...

Good luck,

Mark

[riced_roach]

from the looks of your NO readings, check your EGR valve, probably sticking open when it's hot...

Good luck,

Mark

IF that was the case he wouldn't have a NOX problem since the air/fuel mixture would be diluted with inert gas. To test the egr get a mightyvac or any vacuum gun and apply a vacuum to the egr and if the idle runs rough then you know its working and if it doesn't effect the idle then you either have a torn diaphragm or carbon plugged passage. I am not certain if the egr is the positive type or the negative but regarless it should effect the idle with vacuum applied.

The catalytic converter requires the presents of CO and HC to "reduce" the NOX. Rhodium in the catalytic converter is responsible for this. By looking at the readings your carbs are set too lean. Richen it up.

As far as using a raytek temp gun to see if the cat is working that is not a real good indicator if the cat is working. Efficiency is determined by doing a precat test and post cat (tailpipe which you already have) this test is bullshit because it only really shows the oxidation side of the cat (2 way). A TWC (three way cat) has the rhodium component that reduces nox. I've seen beautiful readings from a cat which passes a catalytic efficiency test but fail horribly in the nox department.

Just by putting a new cat wont help in some cases.

[Silver86LX]

Well, I took my car in for the second test and it failed again. My NO rading was even higher this time ay about 2700 ppm. I took it to a shop and had a diagnostic run and it turned out my carb was leaning out and my EGR valve wasn't functioning properly. So $311 later, my car finally passed the emissions test.

[Mike's89AccordLX]

Holy cow that sucks! Well at least you're legal unlike some of us