Additional fuel pump (Freelander 2)

Pos.	Spare part number	Name
1	-	Fuel line nipple
2	-	Check valve
3	-	Electromagnet winding
4	-	Plunger
5	-	Filter element
6	-	Fuel line nipple
7	-	Sealing ring
8	-	Spring
9	-	Piston
10	-	Sleeve

The additional fuel pump is mounted on the right side of the fuel tank and regulates the fuel supply to the fuel-fired auxiliary heater. The self-priming pump with electromagnetic drive is controlled by pulse-width modulated signals from the control module in the FFBH. When de-energized, the pump forcibly stops the fuel supply to the auxiliary heater module.

The winding of the additional fuel pump electromagnet is installed on the housing, in which the plunger and piston are located. The piston is located in the bushing, which is acted upon by a spring, resting its other end against the plunger. At the entrance to the housing there is a nipple for connecting the fuel line and a replaceable fuel filter. At the exit from the housing there is a nipple for connecting the fuel line and a check valve.

When the solenoid winding is de-energized, the spring holds the piston and plunger in a position that closes the fuel supply to the pump housing. The sealing ring ensures the plunger is tight and prevents fuel from entering from the filter through the pump. When the winding is energized, the piston and plunger move forward, towards the outlet end of the pump housing, until the piston contacts the bushing. In this case, fuel enters the pump through the inlet connection nipple and the filter. The initial displacement of the piston also closes the transverse holes in the bushing, and isolates the discharge cavity at the outlet end of the pump housing. Further advancement of the piston forces fuel out of the discharge chamber through the check valve into the pipeline leading to the additional fuel-fired heater. After the solenoid winding is de-energized, the spring returns the piston and plunger back to the position that closes the pump. As the piston and plunger are retracted to the closed position, the fuel bypasses the plunger through the annular gaps and transverse holes in the sleeve and again fills the discharge cavity.