| Low-pressure electric pump | Carbureted gasoline engines | Approximately 4–7 psi | Inline or near the fuel tank | Match the carburetor’s pressure requirement; check fuel compatibility, voltage, mounting orientation, and required flow. | Excess pressure can overwhelm a carburetor needle and seat. Use a pressure regulator if the pump and carburetor specifications require one. |
| In-tank EFI pump | Many gasoline engines with port fuel injection | Often approximately 40–60 psi | Inside the fuel tank, usually as part of a pump module | Check vehicle-specific fit, electrical connector, module design, pressure, flow at operating pressure, and fuel-level sender compatibility. | EFI pressure varies by vehicle. Confirm the required specification in the service information rather than relying on a general range. |
| External high-pressure EFI pump | Port-injected vehicles where an external pump is specified or properly engineered | Commonly within the port-injection range of approximately 40–60 psi | Inline, generally close to the tank and mounted as specified by the pump maker | Verify pressure and flow under load, inlet supply, wiring capacity, fuel-line rating, filtration, and mounting requirements. | Many external pumps are designed to receive a reliable fuel supply at the inlet; installation details affect performance and service life. |
| Gasoline direct-injection low-pressure supply pump | Vehicles with gasoline direct injection (GDI), as the supply stage | Vehicle-specific; some systems operate at higher low-side pressure than port-injection systems | Usually in the tank or within a vehicle-specific fuel module | Match the exact vehicle, control strategy, pressure specification, module, and electrical connections. | This is not the engine-driven high-pressure pump that supplies a GDI fuel rail. Do not substitute a generic port-injection pump without verified compatibility. |
| Electric diesel lift or transfer pump | Diesel engines requiring low-pressure fuel delivery to the injection system | System-specific; follow the vehicle or engine manufacturer’s specification | Tank-mounted or inline, depending on the original system | Check diesel-fuel compatibility, required flow, pressure, filtration, priming method, and whether the system uses a lift pump. | Diesel fuel systems differ widely. A transfer pump is not a replacement for a high-pressure injection pump. |