On an 83 240T, I think the vacuum line comes off the intake manifold and goes to the advance/retard cannister on the distributor. Somewhere in the line is a Tee fitting to which another line is connected that goes to the blue sensor mounted in the engine block. The blue sensor has two vacuum ports. The other port goes to the regulator. In this line a delay valve is fitted that is black on one side and gray on the other side. I forget which color goes in which direction. The Bentley manual explains all of this. If you do not have the blue switch/sensor, you need to get one. I forget what it is called, but it is the only sensor in the block with vacuum ports. I believe it does not affect normal running. It provides enrichment during cold starts and warm ups.

There are three control pressure regulators that can be used on a 240T. I think the Bentley manual explains the differences.

Philip Bradley