The HEUI injector consists of three important parts

The HEUI injector consists of three important parts

Upper part, or actuator (A)

Middle part, or pumping device (B)

Lower part, or nozzle assembly (C)

The upper part (A) includes the following parts:

Solenoid valve (1)

Armature spring (2)

Armature (3)

Seat pin (4)

Spool valve spring (5)

Spool valve (6)

Intensifier piston one-way ball (7)

The middle part of the injector (B) includes the following parts:

Intensifier Piston (8)

Return spring (9)

Plunger (10)

Plunger sleeve (11)

The lower part of the injector (C) includes the following parts:

Nozzle housing (12)

Oil inlet check valve (13)

Stop (14)

Nozzle Spring (15)

Check valve piston (16)

Bush (17)

Reverse flow check valve (18)

Nozzle check valve (19)

Nozzle tip (20)

These components work together to produce different levels of fuel injection. The fuel injection level is electronically controlled by the performance software in the ECM.