Here's how to safely wire-up an electric fuel pump using a common 40-amp ISO NO/NC (normally open/normally closed) relay (for minimal voltage drop) and an oil pressure safety switch (for maximum ...

If engine oil is the lifeline of your engine, then fuel is its source of food. In applications such as gas- or diesel-powered on-road vehicles, a fuel pump is tasked with delivering fuel in liquid ...

At that point the switch will close, allowing the fuel pump to run. An abnormally long crank time or a no-start could indicate a faulty oil-pressure switch ( Image C ).