Help ..190E 2.3 question

[graybenz190E]

I have an 86 190E 2.3 and looking for some help..

When you start the car it runs 3 seconds and then dies immediately..I figured out that the pump shuts off ??......I bypassed the fuel pump relay like I saw on a post to test the fuel pump and the car runs great..
So I replaced the fuel pump relay and the OVP but that has not worked and the car still dies..I have checked every fuse in the car and most of the electrical wires....Is there anything else that sends a signal to the fuel pump relay that I am missing....or any idea why my pump shuts off..
I have been trying to figure this out for some time with no success...plus I have no Benz dealer or technician in my area.....

Has anyone ever seen this type of problem...any suggestions ??...Please help me get my old girl back on the road ...I miss driving my Benz