Removed door on my 1985 300d and then the car wouldnt turn off.....Im guessing its just cause I havnt reattached the vaccuum lines going to the door...Its just funny that the door mechanism somehow affects the ignition!!! lol

 

You are correct. The Vacuum Shutoff Valve on the Fuel Injection Pump has to have enough Vacuum available to shut down the Engine. When you turn the Key to shutoff there is yet another Vacuum Valve attached to the Steering Colum Lock that sends the Vacuum to the Vacuum Shutoff on the Fuel Injection Pump.