The electric fuel pump is central to the fuel management system. It must precisely deliver pressurized fuel in exacting quantities at every level of performance. Failure of this critical component will result in poor performance, stalling, and a no start condition.
Fuel Pump Designs
ROLLER – CELL
The ROLLER-CELL type was originally developed for externally mounted fuel pumps. In this design a star wheel is rotated which contains rollers. As the rollers glide along the pump race, vacuum is created drawing in fuel from the tank and pressure is created propelling the fuel out of the pump. The reason it is so popular is this design will support high volume fuel delivery.
INTERNAL GEAR
The INTERNAL-GEAR is another push/pull design similar to the roller except with limited pressure sustainability and flow volume. In this design an inner gear turns within a stationary outer gear creating the pulling/pushing of fuel. This design is most often used in “in-tank” fuel pumps.
PERIPHERAL
The PERIPHERAL design is a plastic impeller which turns between two opposing aluminum facings. Where the fuel is pulled in and then pushed out at points directly next to one another. This is the standard type of pump used on almost all vehicles today. Unlike prior types of pumps, these units are virtually pulse free where by the fuel delivery is continuous instead of pulsing like with the roller or gear. These pumps are much quieter than the other two types, but again have limited pressure and flow characteristics as compared to the roller type.
The Python Plus Electric Fuel Pump
The armature is surge tested for air /layered shorts or opens. Failed units are discarded.
Commutators are surge tested for shorts/opens. Good units are sanded and undercut. Failed commutators are replaced.
All brushing surfaces failing to meet surface and diameter standards are discarded.
The roller race plate is renewed with a highly chemically resistant and low wearing material.
The roller plate and rollers must meet diameter and surface standards or they are discarded.
The pressure limiter is tested for proper seal and pressure engagement. Failed units are replaced.
All internal O-rings are replaced.
All final assembled pumps are tested for the following:
