Hook both the brown lines up to the valve at the ignition, in the manner which you think is "correct".

Disconnect the supply line from the three/four-way connector. Make sure the line that goes to the shutoff solenoid on the pump is properly connected. Now, start the car. Hook the hand-held pump up to the supply line (the one you disconnected). Turn the key to off. Pump hell out of the mightyvac. If the car doesn't turn off, try switching the lines at the ignition and repeat.

This assuming your shutoff solenoid is 100%.

If the car doesn't turn off with the lines in either configuration (your shutoff solenoid is definitely good, ya?) then I'd feel pretty comfortable saying the shutoff valve is defective.

Also, NEVER, EVER, EVER, EVER (EVER!!) try to run the car with the line to the oil-pressure gauge disconnected. It'll fill your car with oil. Believe me.

Jay.

__________________
On the road, currently:
'83 300D (German spec.) 168k mi. - - Wolfgang (tucked snugly away for the winter!)
'87 300D 375k mi. - finally went over to "The Dark Side"
'87 300TD 225k mi.
Cannondale 66cm CAAD5 w/Campy/Jamis Aurora
Hujsak Custom Fixie/Landshark Track Shark Custom/Ahearne Custom 29'er