Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Fuel pump wiring

Hi my 4/4 Zetec failed to start. Checked pump no feed bridged out relay pump runs.
The yellow black wire which needs to be earthed to operate the relay is linked to the inertia switch then disappears in to the loom under dash.
I can’t find any yellow and back wires.
Any one know where it goes befor it earths out
I have cut wire and grounded at relay runs fine.

I assume you refer to the fuel pump relay, the black/yellow wire from the relay should go to the engine harness, here I expect that is then routed to the ECU which 'grounds' one side of the relay coil to turn the fuel pump on. When the ignition is turned on the ECU turns the fuel pump on for a few seconds to fill the injector header rail, then the pump is turned off. Not too sure but assume the ECU then needs to see a signal from the crankshaft position sensor in order to know the engine is turning over and to know it can turn the pump on. If the engine isn't turning over / running there will be no power to the pump following the initial few seconds following ignition on.