I need help from the A1 wizards. I just took in my '84 GTI to the
reinstated emissions testing (in Connecticut) and it failed on the NOx test.

The limits for my car are:
HC(PPM) 278
CO (%) 1.11
NOx (PPM) 1944

My car read:
HC(PPM) 83 (Pass)
CO (%) 0.85 (Pass)
NOx (PPM) 2345 (Fail)


Will adjusting the CO to spec (0.21%) for the car have any affect on the
NOx? The guy who performed the test suggested that failing the NOx portion
of the test indicates some problem with the EGR system.

Any suggestions on how to lower the NOx emissions?

Thanks,
VJS

Did you replace plugs/cap/rotor/air filter? It's close enough that a
little tweak might do it.

On Wed, 19 Nov 2003 18:16:22 GMT, "Victor Silva"
<news (AT) NOSPAM (DOT) victorjsilva.com> wrote:

The car is always maintained and all the things you mentioned are fairly
new.
I think those components would affect mostly the HC.

I did a search on the web for the cause of Nitrous Oxides and it's mostly
from running the timing too advanced. It was running slightly advanced, so
I set it the timing to spec and put in a couple of bottles of Isopropyl
alcohol. It passed now.

Thanks for the response.

--VJS

"Darryl" <umpolung (AT) REMOVEhotmail (DOT) com> wrote

Hi Victor,
I have the same problem in my '91 passat (failing the NOx limit 0-15mph). In your case, when you say adjusted the timing, what exactly did you do? Please bear with me, I am a auto novice...can you explain what exactly you did to get it to pass?
Thanks,
M.Bell

Hi,

Adjust the timing means: loosen the distributor clamp, attach a timing light
and point it into the hole on the transmission bell housing after removing
the screw on plastic cap. Turn the body of the distributor to align the
timing mark per spec.

If you don't know what this means I suggest you pick up a service manual.
You could wing it if you don't have the proper equipment by marking the
present position of the distributor and turn it clockwise so that the marks
are about 1/8 to 1/4 inch apart (This retards the timing a small but unknown
amount). Then retighten the clamp bolt. Throw in a couple of bottles of
isopropyl (or ethanol) and go take the test. When you get back home loosen
the distributor clamp and realign the marks you made previously and
retighten and your good to go. This is not for the faint of heart and I
don't suggest you go this route if you are inexperienced.
I take no responsibility for any damage incurred if you perform these
procedures (it's sad that we live in a world where I have to make this
statement).

Regards,

My original post ====================VVVVV
I did a search on the web for the cause of Nitrous Oxides and it's mostly
from running the timing too advanced. It was running slightly advanced, so
I set it the timing to spec and put in a couple of bottles of Isopropyl
alcohol. It passed now.

"mirabell" <anumani (AT) sbcglobal (DOT) net> wrote

Please bear with me, I am a auto novice...can you explain what exactly you
did to get it to pass?