I was reconstructing the vacuum hosing in my 1990 760 Turbo. By the time I got to this car, some of the vacuum tubes and fuel lines had already been removed. There is a tube, in the diagram, that comes out of the firewall (supposedly leading up to the pressure gauge on the other side) and is supposed to connect to the intake manifold. By the time I got to the car, there was indeed a tube coming out of the firewall, but it didn't lead all the way up to the intake manifold. It was hanging there loose with a T connector at the end. I see no good reason for the tubing to split at this point, but I wanted to double check with everyone. The best I can figure, whoever worked on this car in the past used the T connector as a joiner to connect the wider tube coming out of the firewall to a narrower tube leading up to the manifold. This seems a bit insane to me since having a leak out of the unused portion of the T would completely mess up the pressure reading, but I can't think of any other reason it would be there other than as a joiner for pipes of different sizes, like I said. Any insights?

Thanks!
Rosa