Sealey VSE212 - Manual (Page 3)

4. GENERAL INFORMATION
Because fuel systems and access points are so varied, it is impractical to list all of the applications. Always refer to a reliable workshop manual, or
the car manufacturer for the recommended test procedure and access points before commencing any work on fuel injection systems.
There are two basic types of fuel injection systems. Port Fuel Injection (PFI) (fig.1) uses separate injectors to supply the fuel to each cylinder.
Throttle Body Injection (TBI) (fig.2) injects fuel from a position above the throttle plate on the intake manifold. On both systems there is a supply
side, which brings fuel to the injectors, and a return side which brings unused fuel back to the tank.
5. bASIC PORT FUEL INjECTION (PFI) SYSTEM
6. bASIC THROTTLE bODY INjECTION (TbI) SYSTEM.
fig.1
fig.2
Original Language Version VSE212 Issue: 1 -06/05/11