[Supras] Emissions failure

[Bob]

Dang... What don't you know?

Does NJ have an exception in the law that allows older cars with expensive
repairs to be exempted?

I know that California has some sort of an exemption.  I don't know the
exact amount but I was told if the car needs much more than a set of spark
plugs you would be most likely over the exemption amount.  

I've smogged 4 cars in California and even a 190K Acura Vigor passed easily.


Is NJ that much harsher?  It's not like the state has a reputation for the
wonderful clean air there...

Bob

-----Original Message-----
From: supras-bounces at supras.com [mailto:supras-bounces at supras.com] On Behalf
Of berniek at technicaldevelop.com
Sent: Friday, August 04, 2006 9:45 PM
To: Mike Scharf; wwt3198 at yahoo.com
Cc: Supras at supras.com
Subject: Re: [Supras] Emissions failure

I live in NJ too, and have found that if you happen to be a little careless
in setting the spark timing to late by 10-15 degrees, the HC and CO content
decrease.  I have read but not observed that the NOx emissions will increase
with too much retard, however.  Are you certain the EGR is working
correctly?  Are the valve passages plugged?  The NJ dyno test is conducted
at 15 MPH which may or may not open the EGR valve (it is vacuum operated
from a port in the throttle body).  If the spark is retarded, more throttle
will be required to reach 15 MPH with the load applied, possibly opening the
EGR valve to reduce NOx.  EGR reduces the high temperature spike in
combusion, which causes fixation of nitrogen to nitrogen oxides.  Years ago,
a GM engineer characterized it as "throwing an ice cube into a bowl of hot
soup".  

I have gotten through inspection with a '92 V6 maxima (mule car for us) with
fuel injectors partially clogged to the point where the idle was rough by
being "careless".  Recently changed all of the injectors on that car (bitch
of a job with the upper intake manifold) and the HC dropped only slightly
although the idle and purr of the engine under load are much better.  HC was
84 PPM, CO was very low as was NOx, just a week ago at the Randolph
inspection station.  HC is primarily caused by a misfire, while CO is caused
by incomplete (rich) combustion.  I changed spark plugs in that car a couple
of weeks ago, a very important consideration for HC.  

The Supra always passed, and is essentially stock except for mild boost
increase and a large but quiet HKS exhaust.  It is out of commission now due
to a BHG, and I'm still rebuilding a JDM engine for it.  

    Sun used to make a "do it yourself" HC and CO analyzer which I bought
from JC Penny maybe 25 years ago.  It works by exhaust gas thermal thermal
conductivity using two measuring cells:  One for the raw exhaust gas and a
second after an activated charcoal filter to remove HC but not CO (they do
not tell you this, but the charcoal needs to be outgassed periodically by
removing it and oven heating it at 400-500F).  They use simple analog
electronic circuitry to do the subtraction to differentiate CO+HC to
separate readings.  One of these might be available on ebay.  It was a
couple of hundred dollars, as opposed to $2000-$3000 for infra-red
absorption types on the market at the time.  But prices of those on ebay
might be low as well.  It pays to experiment in your garage before going to
inspection.  

    Good luck.

        BernieK
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