For carburetted engine, there is an ECU, Emission Control Unit, which controls the various solenoids and valves but is not related to the fuel pump relay.
If you do not have any power from the ignition terminal, that is the problem you need to address. Ignition terminal receives its pulse from the ignition coil and would only work while engine is being cranked or is running.
Oil pressure switch is not related to the fuel pump relay operations.
Check the continuity of the Blue wire from ignition coil. If the tachimeter is not working, the ignition coil could be faulty.
Using a toggle switch works but is not safe as the fuel pump would not cut off when engine stalls and that is a safety hazard.
Friday, November 23rd, 2018 AT 6:51 PM