Fuel Injectors

Fuel injectors are supplied with battery (system) voltage through power supply relay, and are controlled (grounded) by the ECM. See Fig 1 . Injectors are opened sequentially in cylinder firing order. Fuel quantity is determined by injector on time (duty cycle).

Fig 1: Identifying Fuel Control System Components (VR6 Is Shown; 4-Cylinder Is Similar)

Courtesy of VOLKSWAGEN UNITED STATES, INC.