The electric fuel pump activates when the fuel feeder line pressure falls below how many psi?

• A. 2 psi
• B. 5 psi
• C. 8 psi
• D. 12 psi

Answer: (B)

A low-pressure switch in the fuel system energizes the electric pump when the feeder line pressure drops to a small, safe minimum. Setting that threshold around 5 psi ensures the pump will run to rebuild pressure quickly, helping the engine start reliably and keeping fuel delivery steady, without the pump cycling on too often. If pressure falls below this point, the pump turns on to restore fuel pressure; choices like 2 psi would risk poor prime reliability, while higher values (8 or 12 psi) would keep the pump running longer than necessary. So 5 psi is the practical triggering point.