I have a 1990 240 dl that starts then stalls after about 4 seconds. The fuel pump in the tank and on the rail have been changed along with the fuel filter.
We've tried changing the ecm and the fuel pump relay from a running car with no luck.
Any thoughts on where to go next?

 

Un plug the mass air flow sensor.
Start the car.
Any change?

 

Why were the fuel pumps replaced? Was the car running before the changes? Helps to provide some history in order to get some idea where we are coming from...

 

No change after unplugging the mass air sensor.

 

Lack of power on hills was the first indication something was going wrong.
The car died the following day when accelerating and had to be towed home. When inspecting the wires to the fuel pump in the tank it was noticed they were damaged. The fuel gage didn't work so both were replaced.
The car starts and will run about 5 seconds then stalls. The second pump was replaced as well at the advice on another posting. The filter on the rail was changed too.