From: Valur Svansson [vsvansson@mediaone.net]
Sent: Tuesday, January 09, 2001 8:23 PM
To: 928
Subject: [928] Failed Emmissions-Running to Rich!

Hey folks,

I thought I would post a neutral and insightful response to my issue for
other cat free folks.
Thanks Mike for your (non-political laced) perspective.
I will keep everyone updated on the Mike's recommendations and my results.
Valur
-----Original Message-----
From:	mlschmidt@sprintmail.com [mailto:mlschmidt@sprintmail.com]
Sent:	Monday, January 08, 2001 3:37 AM
To:	vsvansson@mediaone.net
Subject:	Re: Catbypass - Failed Emmissions- Duh!

I'm sure you're probably going to get all kinds of responses on this, with
some differing opinions and suggestions.
>So Team 928, my questions are:

>1. Am I running to rich?
You could be. If you adjusted your fuel pressure regulator for maximum power
you've almost certainly increased the fuel pressure. This richens the
mixture. Not too rich for maximum power, but too rich to pass an emissions
test.
>2. Is there an adverse affect the car in running rich? Does it affect
power?
Running richer will lower your gas mileage. If you're way to rich you'll
foul your spark plugs faster. Running too rich will also cost you some
power, but from a strictly power point of view, you're better off a little
too rich than too lean. If you adjusted the fuel pressure regulator on a
dyno, you should be at the best mixture for power, but richer than the car
was stock.
>3. I thought that a Chip makes the car run lean?
Chips will make the car run richer and advance the timing. Some chips will
also raise the limit at which the rev limiter kicks in.
>4. How can I fix it without going to the Dyno again ($100)
Measure the fuel pressure with the car as it is now, the way you adjusted it
to on the dyno. You can then change the fuel pressure back to what the stock
pressure was, and then return it to the setting you got from the dyno tuning
when you want to. Many guys lower their fuel pressure to the stock setting
for an emissions test, and then set it back to the higher pressure from
their tuning after the test. On the 928 Specialists web page that has the
adjustable fuel pressure regulators for sale, it even says: "Note:
Adjustable Fuel Pressure Regulators are intended to be used off road *only*
when set at a higher than stock fuel pressure but can be adjusted quickly
from a track setting back to one for street emissions regulations."
>5. Can I lean out the car and will I then pass?
You could very well pass then. There are some other things that might affect
your ability to pass, but I'd guess that the higher fuel pressure would be
the main issue. You even said that the emissions test guy mentioned a
possibly broken fuel pressure regulator. Yours isn't broken, but it is set
to a higher than stock pressure. If you compared it to the pressure that a
stock fuel pressure regulator is supposed to provide, then technically it
would appear broken.
>6. Should I just put the Cats on to pass or should I just address this Rich
>thing?
I'd definitely set the fuel pressure regulator so that the pressure is back
to the stock same as it was with the stock regulator. Check what the
pressure is set at now first though. That way you can return it to the tuned
pressure without another trip to the dyno. If you want to be sure, put the
cats on for the test too.
>The only reason I bothered  to ask was due to the "urban legend "  that the
>928 has a tendency to pass emissions without cats and that if that was true
>then my running rich could have caused me to fail.

That's definitely NOT an urban legend. Your running rich could definitely be
what caused you to fail. I also have a 1988 928S4 with an automatic
transmission. I have passed an emissions test with no cats and a set of
Autothority chips in the car. The car's emissions weren't even anywhere near
the levels that would have been required to fail. At that time the test
being done was one of the tail pipe sniffer tests, with the car standing
still but the engine speed being increased. Many places are now using a
treadmill type of setup, so that may affect things to some degree.  In any
case, I'd guess that the majority of your problem is that the fuel pressure
is set higher than stock.
Good luck.
Mike Schmidt
'88 928S4 Black/Black "PORSCHE" cloth
928 Owners Club Charter Member
PCA Chicago Region