Cadillac: ECU, engine vacuum, vacuum line

Question
This ECU has a vacuum tube on it,is this for the barometer and is there a way to verify if the ECU is working properly
I have still black smoke coming out of the exhaust to much feul any coments
Thanks for your patience

Answer
That black tube is measuring engine vacuum and if you disconnect or have  fault in the line with the engine running it destroys the computer.

Therefore, install a new computer and replace this vacuum line and make sure it stays on the engine and the ECU or as soon as you start the engine you will destroy the new computer.