What is a likely cause of low fuel transfer pump pressure?

• A. Plugged fuel filter.
• B. Return line restriction.
• C. Regulating valve stuck closed.
• D. Leaking fuel tank vent.

Answer: (A)

Fuel transfer pump pressure depends on how freely fuel can move from the tank to the engine. When the fuel filter is plugged, it creates a significant restriction in the fuel path. The pump then has to push fuel through the blockage, which reduces the flow and causes the pressure on the discharge side to drop. Replacing the filter removes the bottleneck and allows the pump to deliver proper pressure again.

Other options don’t fit as well: a restricted return line tends to affect how fuel is cycled back to the tank and can raise more than lower pressure in the system, a regulating valve stuck closed would typically cause higher pressure upstream rather than a low discharge pressure, and a leaking tank vent can cause air ingress and starvation only under certain conditions rather than a consistent drop in pump pressure.