Do you have an aftermarket antenna also? I remeber on my 190E we replaced the power antenna with an aftermartket unit. After installation, the car would not start. I could not hear the fuel pump charging when the key was turned. I figured the fuel pump circuit had a short. When we checked the wiring to the fuel pump, the ground point was the same point for the antenna (in the trunk). I had not tightened the nut on the ground point properly. Once I tightenedd the nut, the car started. Like the above posts, the fuel pump relay might be the culprit, but if work was done to the antenna, the ground point might be worth looking at. Good luck.
'82 300D Turbo 215k miles