SeaDweller

Good morning everyone!!!!!!

For those of you who have been following my saga, and kind enough to chime in, I have another update on my progress with my CIS system.

Yesterday, I did my best to adjust the sensor plate height, but I found it very difficult to determine the proper adjustment. Peering down into the venturi with the boot partially removed, finding the optimal height is pretty much a "guestimate." I gave it my best shot, and then moved on. By the way, the venturi and sensor plate were squeaky clean.

Next, I let the engine come up to operating temperature, and proceeded to "set" the mixuture and idle settings. I spent nearly an hour, going back and forth between the idle and mixture adjustments before arriving at what I believe is the best adjustment I could obtain by ear/feel.

Through all of these adjustments, and even with my final one, there is a roughness in the engine performance in the 2,000rpm to 3,000rpm range. Despite all of my adjustments, I was never able to get this rectified.

This morning, I started the engine from dead cold, monitoring the control pressure, and here are the results:

1. The car started on the first try, struggled a little, then settled into an idle at around 1,000rpm's (where I set the idle last night). I did not get a fast idle for any period of time. The control pressure at start-up was around 2.5 Bar (35psi).
2. The engine ran for around 1 minute, at which time the control pressure had risen to just under 3.5 Bar (50psi), and then started struggling and surging. After a couple of rpm surges, it stalled.
3. I re-started the engine, and while it was struggling, quickly inserted my 3mm allen wrench in the mixture adjustment hole, and richened the mixture slightly, which got the engine idling fine. Control pressure maitained itself at just under 3.5 Bar (50psi).

I've spent hours upon hours of gathering and reading information (both from this BBS and other sources) to learn about this system, and based on this, I have the following comments and questions (remembering of course that I'm certainly not a Porsche mechanic, so correct me at any time!!):

1. It seems to me that I have a minor issue with either the Warm-Up Regulator (WUR), the Auxiliary Air Valve (AAV), or both. I feel the WUR may be coming up to warm operating control pressure to quickly, leaning out the mixuture to soon. It may also have an initial cold start pressure that is too high, again leaning out the mixuture too quickly.
2. Regarding the AAV, I'm not getting a fast idle at all. Doesn't the AAV function to allow a short period of fast idle? Can the AAV be tested? How? Can it be adjusted (it's certainly not easy to access)?
3. Without a gas analyzer and other tools, I could easily be way off on the timing and mixture adjustments. I could also be off on the sensor plate adjustment. Regardless, I believe I'm on the right track, however would it be wise to take the car in to have these things adjusted to spec before I make any changes to the WUR or AAV?

While I have your interest, I have a comment and question on a side item. With the car idling for some time while I was making the mixture adjusments, it started smoking quite a bit. It has smoked slightly at start-up in the past, but now is smoking quite badly when warm. The oil is not overfilled, and I seem to notice that this may have occured after the last oil change. When I bought the car, it did not smoke, and I've only put around 4,000 miles on it. Input?

Thanks everyone!!!!!!!!!!!!!!!!!