Hook a fuel pressure gauge up to the shrader valve on the fuel rail.
Fuel pump pressure test.
Failed injection pump, also test fuel flow from lift pump.
I believe that you can switch the Horn Relay with the Fuel Pump Relay and if the horn no longer works and the Fuel Pump does then that relay went bad... try that, its a sure fire way to know whats wrong... If it checks out good it might be a Defective Fuel Pump.
The fuel pump is located on the top of the fuel tank. The sending unit and fuel pump are one unit. Test access to wiring can be gained by an access cover under the lower back seat. Pump can only be changed by droping the tank. Hope this helps!
Fuel pressure test at the fuel rail.
Fuel Pump Pressure Test Look at the Related links below for help.
A fuel pump pressure test could determine the condition of the fuel pump and fuel system.
Start with a fuel pump pressure test.
Where is the fuel pump fuse and relay on 1994 BMW 525i and how can I test to see why my fuel pump won't work
Your Fuel filter is attached to the fuel pump, which is located in the fuel tank if its a gasoline burning vehicle. Diesels should be located inline.
Test for a broken wire between the fuel pump and power distribution box. Check for bad connectors also.
cant be serten but if u tryed to test the fuel pump before complet install with out disconecting the ecu its likely the ecu is dead