Fuel delivery problem with '89 300SEL

[BrettS]

I’m having a fuel delivery problem with my ’89 300SEL. Every time I start the car, it runs for about 3 or 4 seconds and then dies. The fuel pump relay is known to be good. Jumping power directly to the fuel pump causes the fuel pump to run, allowing the car to start and stay running. Also, jumping between slots 7 (which feeds power to the pump) and 8 (which is always hot) of the socket in which the fuel pump relay is seated causes the fuel pump to run (just like jumping to the fuel pump directly).

With the fuel pump relay in place I checked voltage at each slot of the fuel pump relay receiving socket, in each key position. Here are the results:

slot 2 - 0 voltage with ig. switch in off position; 1.69v in all other positions. (This one seemed strange to me)
slot 4 - 0 voltage in all positions except on cranking/start, then 12v.
slot 6 - 0 voltage in all positions except on cranking/start, then 12v.
slot 7 – 0 voltage in off position, 12v for a second or so in run position prior to start, 12v on crank, 12v in run but only for 3 or 4 seconds then drops to 0v.
slot 8 - 12v in all positions.
slot 9 - 0v in off position, 12v in all others.
slot 10 - 0v in off, and 5v in all other positions.
slot 11 - no voltage in any position (believe this is the ground)
slot 12 - 0v in all positions except crank/start, then 12v.

I would certainly appreciate any advice.
Thanks.
-Brett