So as the title states, I failed emissions today. I acquired this car in May, passing emissions with flying colors then, why the sudden change now?

Background info: the car is running non-sequential turbos with your typical, omnipresent minor oil leaks here and there.

25/25 test____________ 50/15 test
______reading, allowed___ reading, allowed
HC ppm___ 74, 132_______ 90, 136
CO%_____ 3.03 , 0.73___ 0.30, 0.76
NOx ppm__ 64, 945_______ 343, 1045


Emissions tech claims that due to his experience, a high carbon monoxide reading like that in the first test and not the second would indicate that I either needed to "change or replace the egr valve".

From my understanding, the egr valve was blocked off when the previous owner went non-sequential. To reiterate, I passed the car with flying colors a few months ago. Any help would be GREATLY appreciated!

 

Air pump working?

 

Air pump is working.

I'm trying to think of everything I've done to the car since May and it doesn't seem like much. I've been reading all day and I hear not adding idemitsu on the next fill up might help? Maybe an oil change?

 

After air pump, I would suggest oxygen sensor and spark plugs. Oil change would not hurt.

 

Iono, EGR valve failure or not working probably you will have a high NOx Reading not CO.

As Moconnor suggested, I believe the replacing your O2 and spark plugs might help.

Remove your spark plugs to see if they are soaked or carbon build up.

-AzEKnightz

 

failing EGR wouldn't cause high CO, inadequate air to the cat or even a failing cat would. but the fact that the HC levels are decent points to lack of airflow through the ACV from the pump, or the pump isn't engaging during the test.

 

Thanks for the advice so far guys.

After going through everything, I remembered that I adjusted my bov a month back because I thought I was experiencing compressor surge. If anything, I think I might have made it too soft, causing a boost leak, which would in turn cause me to run rich...

It may be a stretch but at this point I'm not willing to overlook anything. I'm adding boost leak/vacuum leak test to the list.

 

Update:

Turns out it was a boost leak due to my bov as well as a cracked coupler! After getting that fixed, CO% decrease from 3.03% to an astonishing 0.06%

 

Could you explain the boost leak die to BOV? Was the BOV not holding pressure? Doesn't seem like it should be seeing much during an emissions test.

FWIW, I had a similar issue recently where the car wasn't passing at 25 mph, and wiring the airpump on at all times seemed to fix it.

 

hi there

I too failed my emissions test last week , purchased the FD a week prior and it came with a passed emissions over a year ago .

i passed the curb idle but failed the drive section, failed HC ppm , limit was 60 and i was 107 . failed NO ppm limit was 450 and i was 497. i did pass the CO% tho .

i barely failed so i wasn't too happy, so i put new spark plus in, new air filter , did an oil change , got rid of the old gas , fuel filter was changed ... even purchased that guaranteed to pass stuff , mostly ethanal in there.

would there be anything else i would need to be doing here??? any ideas would be awesome. thanks