The black line that goes into the cabin is a vent. It's not supposed to be connected to anything in the cabin. There should be two brown vac lines in the engine bay. One solid brown one, which is the vac supply to the ignition. The other is brown with a blue line, which comes from the ignition and goes to the shut-off valve. You can see this line in the photo it goes in between the oil filter housing and in IP. Make sure that line is connected to the shut off valve on the IP and to the ignition.

To test the shut-off valve itself you can remove the brown line comming out of it and plug in a mity vac. Start the car and then give the mity vac a couple of pumps. It should shut the car of quickly and still hold vac. If it does then it's working properly, if not then the shut-off valve is bad.

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