84 BMW 318i ECU or computer problems

I'm going to have to figure exactly what item 5 is on the diagram it's kind of confusing, I do see that it's wired to the ECU. But what is it called, if I knew that I could see a pic on Ebay of what the part looks like and I may know already what it is. I know what the cold start valve is and how that works. Maybe that's the sensor the tells the cold start valve what to do. I could disconnect the cold start valve plug after it's warmed up and that might be not sealing shut after the cold start. That could make it run way too rich and that could be a fault in the valve or the ECU. I do know if the ECU is flaky it can cause all kinds of really weird problems that are hard to diagnose. Thanks for the post.

But also the ECU sparking when put to ground is still not normal, I don't think maybe I need to mount it and see from cold start, what happens. It never did it before. Also I had a 325 and the guy I got it from hooked the battery charger to it backwards and let it charge he said. Later I got it running and it was fine but the ABS light was on and I found there is a module under the steering post inside the car that had a little wire that acted like a fuse and so I took that apart and sure enough the wire was melted like a fuse. replaced it with a little wire the same gauge and it fixed the ABS problem.