Scirocco Gross polluter

[jdbubb at verizon.net (Dan Bubb)]

To add a couple thoughts to Cathy's input.
Since you're on the high end for HC and CO and out of range on NOx I suspect your car is either badly out of tune or your cat/O2 sensor is dead.

NOx is a function of high pressures and temperatures. Advancing ignition from the stock setting (6?) causes peak cylinder pressure to increase a significant amount, so make sure your timing isn't advanced.
Also, you should check and make sure your mixture is set correctly following the procedure in the Bentley.
As Cathy points out it's easy to check the O2 sensor so do that also.
It goes without saying that new gas and oil are a good idea before a test.

If that doesn't get it to pass then your cat is next.

If you can afford it install it with V-band clamps. Pretty expensive, but makes swapping out the cat a 5 minute job instead of screwing around trying to get to the bolts on a three bolt flange.

The Autotech module shouldn't do anything in the range the engine is in during the test, so it won't help you any.


From: "C Boyko" <roccit53@xxxxxxxxx>
To: "Michael Laughlin" <michaelnl@xxxxxxxxxxx>
Cc: "scirocco list mailing list" <scirocco-l@xxxxxxxxxxxx>
Sent: Thursday, November 29, 2007 7:55 AM
Subject: Re: Scirocco Gross polluter


> 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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