Wideband O2 devices

[donau]

I now have a Western Motor Sports (WMS) wideband O2 sensor and monitor in my car for displaying the air to fuel ratio real time all the time.

I also have a question in case anyone here knows the answer. I have posed the same question on Rennlist but so far no replies. The question is: In a Porsche 930 lambda system, where does one connect the orange wire for the tach signal? Connecting it to the negative of the ignition coil makes the display go blank so that obviously is not the correct connecting point in this car . I need this before I can do any data logging with RPMs included.

I chose this product for the following reasons:

1. With a little help, it fits in the spot of my choice
2. the price advantage over Motec PLM (that would also fit in the same slot) is considerable
3. This device shows me everything I need to know regarding AFRs

As for pictures, I tried taking a few but either my camera is bad or I don't know how to set up the lighting exposure properly yet. Most likely the camera is bad (Kodak P850).
Here's two pictures, from one you can just barely see where it is located and in the second picture one can tell that it actually shows numbers. In real life the numbers are actually easy to see. The good news is that the numbers I see are pretty good. Cold Idle ~14.5, warm idle ~13.5, boost ~12.0, cruising ~15.5 (this last one I'd like to have a little lower, looks a bit too lean to my liking, 14.5 - 15.0 would feel comfortable).