DJP

Hello people,

It's that time of year again, and emissions is calling my name. Unfortunately for me though, it's been my second try and i've failed on BOTH attempts. Since i got the car i have had to replace the following this summer:

Radiator
Fuel filter
water pump
timing belt
cat. converter
exhaust manifold
intermediate pipe
hand brake cables
oil pan

On each of the past tests, the NO ppms have been through the ROOF. the first test showed me a reading of 3050 while the second past gave me 3111

the only performance parts i have is a ractive short ram intake with some stainless steel headers...is there anythin that i need to check in order to get this thing back on the road?

slowcivic2k

Might want to start with what car, what engine you have, as well as what emissions equipment you are using, OEM Honda or some off brand.

DJP

sorry bout that, i have a 92 civic si hatch with a d16z6 engine in it. As for the emission question equipment...give me a little time so i can go and look that up...but all the replacement parts besides the exhaust manifold and short ram intake are all aftermarket OEM

thesmogman

O2 sensor. Your HC's must be low on both tests right.

Without proper A/f mixture the cat will not store O2 properly and not reduce the emissions effectively.

You could also have an vacuum leak or exhaust leak that would cause the same results. If no leaks then O2 sensor.

Is the motor stock? as in milled head or H-C pistons or anything like that?

Did you fail for anything else like timing or???

DJP

The motor itself is stock..and the only thing at this point that hasen't been changed in the exhaust system is the O2 sensor. As for a vacuum leak how would i be able to find that...from the gas pressure test that was performed during the test it passed with flying colours...futhermore, i had recently done a compression test on the motor as well, and things were runnning smooth. I've been under the car a tone of times this summer, and it doesn't look like there are any leaks in the exhaust from what i have seen.

As for HC's the 40km/h test has a limit of 75 and i' at 39. with the curbe idle the limit is 200 and i'm at 28


Modified by DJP at 10:37 AM 8/18/2007

thesmogman

With your nox that high are you sure about the cat. The Nox reading is at a level that you would see without a cat. How new is the cat?
If you ran it that way for a year then the cat might be gone again.

If it were my car I would check all the vacuum lines for cracks and do a decarbon treatment then an O2 sensor and give it a try.

Do they check your timing? I would set it either at spec or 2 degrees below it. So if your spec is at 16btdc set it to 14btdc. If 12 then 10. this will lower the nox a bit. say 250ppm's not 2000 though.

ddd4114

A high NOx count pretty much means that your combustion chamber temperatures are too high, which should not happen with a stock engine. I really doubt an intake and header are affecting emissions that much...

As stated, a failing cat can also cause high NOx readings, but you said you replaced yours.

Definitely check your timing. Since you replaced the timing belt, check both mechanical and ignition timing. I would take thesmogman's suggestion and retard your ignition timing a little for your next inspection.

I would also run some injector cleaner and/or Seafoam to try and clean out carbon deposits.

How do your spark plugs look?

Good luck.

DJP

Thanks for all the help you peopl have been giving me so far. As for my spark plugs, the last time i checked they looked normal...no oil was being burned by them. As for the 02 sensor, i checked that out during the time i replaced the exhaust manifold (January) during that time it still looked like it was in good shape. Is it stilll possible for it to start failing by now without out a check engine light coming on though?

DJP

bump