The relay board has an onboard fuel pump relay that will work for smaller fuel pumps. The Walbro GSL392, for example, will work fine at normal fuel pressures. We used one like this on our Chevy Nova project. But if you’re running a bigger fuel pump like an A1000, we recommend avoiding running the current through the relay board’s printed circuit board and screw terminals. This drawing shows how to add an extra relay. We recommend this if your fuel pump current draw is over 10 amps.