There is a round metalic "engine shut off valve" attached to the back of the fuel injection pump. this valve has one vacuum connection that should be attached to a black rubber connector.

A plastic vacuum line (brown or brown and blue) should go from the black connector to a grommet passing through the firewall (steel panel) to the rear of the ignition switch. If the line has come off, reconnect it.

Caution: if the line is intact, the rubber diaphram in the shutoff valve could be leaking which may cause engine oil to be sucked into the vacuum system causing further damage. I suggest you do not use the car until you find and repair the problem to avoid more damage. Check to make sure that the vacuum take offs on the large vacuum pipe from the vacuum pump to the brake booster, are clear and have vacuum present.

Good luck.

Acky