[Shotimes] Re: Shotimes] High NOX

[Alan Fanning]

High Nox is usually a result of a malfunctioning EGR system for those of us
with Calif cars or ATX's. Without EGR, I would look at the cat's as a
possible issue, or ay engine mod's that would result in non-optimal air/fuel
ratio.

For smog testing purposes you can pull the shorting plug located adjacent to
the plug used to pull the codes. This will reduce the timing which then
reduces Nox. The car drives like a "pig" tho', so don't try to go far this
way.

    Alan



> From: TBailSHO@aol.com
> Date: Thu, 20 Oct 2005 22:55:01 EDT
> To: shotimes@autox.team.net
> Subject: [Shotimes] High NOX
> 
> I recently ran my 91' through the state of Ohio version of the semiannual
> required emission test.  All test results were well within limits with the
> exeption of the Nox which had a reading of 865 PPM against a bogey of 878.  In
> other 
> words I made it by the skin of my teeth.  The good news is that my county
> will no longer be a tested area after the first of the year.  My concerns are
> if 
> I am doing damage to my car, or if the ozone layer over southern Ohio will
> have a big hole in it because of me.
> 
> My research of this problem has indicated high combustion chamber
> temperatures can be a cause of this.  Some information about my car which
> probably isn't 
> pertinent is; 88K, 60K done in two steps, top of engine at 70 thou. and front
> at 80 K.  All generally recommended parts replaced at those services except
> plug wires which are original.  I've been running regular gas for about 3
> years, 
> mods are very early version SHO Shop Y pipe, stock cat back with Dynamax
> super turbos, Pro-M 77 MAF.  Thats about it I guess.  The car runs like a top,
> 21-22 MPG on my local commute which is a mix of freeway and city surface
> streets 
> and high 20's on the highway.
> 
> Anyone else had to deal with this problem,  or have some ideas as to what I
> might look at? Thanks for any input.  I have been on the list for many years,
> mainly a lurker but enjoy reading over the many topics that are covered and
> have learned a lot about maintaining  my 'old friend.'
> 
> Tom Bailey
> Dayton, OH