Scirocco Gross polluter

[roccit53 at gmail.com (C Boyko)]

Well, that HC and CO isn't awful, is it, I mean, they may just pass on
another run. But those could easly end up near zero, so they're not perect
for sure.My understanding of how the three are produced:
NOx is hard to produce under normal conditions because atmospheric nitrogen
is pretty stable. But if you subject it to a very hot/squished cylinder
event, it will be created. Hot (lean) we can do something about by richening
some, "squished" is likely a factor of the engine  design(and 16Vs are
pretty high compression) though timing of the ignition event impacts that.
HC and CO often go hand in hand, they are indicative of incomplete
combustion for whatever reason. First, they always advise fresh oil ( as it
can get pretty stinky), and fresh plugs. Neither is a bad thing for the car
anyway. High test also is generally advised too. But as far as what it
indicates about your engine tune is:
a) there is too much gas to burn properly (too rich)
b) there is way too little gas to burn (this seems odd, but overly lean
mixes don't burn as well as they should and send HCs down the tailpipe)
c) spark is coming in at a time when the piston is at a poor spot to allow
for a complete burn ( ignition timing) Go on the Innnovate site and look up
the Notes from Klaus for a good article on ignition timing. Not my Klaus
BTW.
Other things: If your O2 sensor is dead, the -E part of CIS-E can't fine
tune your mixture, so it runs on limp home mode. I'm pretty sure this is a
too rich situation, but if it had run like that for a while, it may have
killed the catalytic converter. And finally, how is you cat? If it's dead,
it can't eat up that excess stuff. I was very frustrated etesting my 16V,
because I just couldn't tune it to get it to pass. But a new cat solved it
beautifully. I got mine put on 3 bolt flanges, so I could put it in for the
test every time, that way I knew it was in good shape. Then I bolted a
similar looking hollow one in for the rest of the year, if the car was
running rich, I knew I wasn't killing the cat (I was killing the air I
guess) Maybe tonight I'll dig up my before and after cat ETest numbers. I
bet a fresh cat would fix yours up, they're pretty good at eating NOx, and
tht little bit of HC that needs to go away for a pass would go away too.

On Nov 28, 2007 9:37 PM, Michael Laughlin <michaelnl@xxxxxxxxxxx> wrote:

> My HC was 115/46 (max 130/105) and CO was .60/.38 (max .80/.69) ...  would
> getting an autotech fuel module help it not run lean?  It would add a little
> more power too but, it might cause other issues and I don't really have the
> cash right now (although, I would like to add it eventually).
>
>  ------------------------------
> Date: Wed, 28 Nov 2007 21:24:37 -0500
> From: roccit53@xxxxxxxxx
> To: michaelnl@xxxxxxxxxxx
> Subject: Re: Scirocco Gross polluter
> CC: scirocco-l@xxxxxxxxxxxx
>
>
> How was HC and CO? High NOx is usually a problem if you're running lean
> (and have high compression, as in a 16V) or at least that's my
> understanding. My 2L 16V often had both high HC and NOx, and a newer cat
> solved it nicely.
>
> On Nov 28, 2007 9:00 PM, Michael Laughlin <michaelnl@xxxxxxxxxxx> wrote:
>
>
> Sorry to return to the list after so long and be more of a lurker not
> poster but, my 88 16v arrived Friday from my home state of Pennsylvania and
> I finally got the paperwork today that would allow me to register it in
> California.   I was very excited and took it to get smogged after work and
> then.....
>
> FAIL
>
> It says that NO was measured at 2380/1048 and max was supposed to be
> 835/774. They also claimed that the vaccum lines to some unnamed sensors
> were disconnected (possible) and the fuel evaporative control was modified
> (don't think I ever touched that).
>
> I do have a 1.8l to 2.0l conversion, cams and intake but, the car passed
> in Cali in 2000 with this set up.    Does it sound like I can fix a few
> simple things or will this require me to sell the car out of state?
>
>
> -Mike
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