Air/Fuel Delivery System

COMPONENTS
The main components of this system are the fuel tank, fuel pump, fuel filter, Throttle Body Fuel Injection (TBI) unit (including the fuel injector, fuel pressure regulator and Idle Speed Control [ISC] motor), fuel feed pipe, fuel return pipe and Air Cleaner.

OPERATION
The fuel in the fuel tank is pumped by the fuel pump, filtered by the fuel filter and fed under pressure to the fuel injector installed in the TBI unit. Fuel pressure applied to the fuel injector (the fuel pressure in the fuel feed pipe) is always kept higher than the fuel pressure in the intake manifold by the fuel pressure regulator. The fuel is injected into the TBI unit in conic dispersion when the injector opens according to the injection signal from the Powertrain Control Module (PCM). The fuel pressure that is regulated by the pressure regulator is returned to the fuel tank through the fuel return pipe. The injected fuel is mixed with the air which has been filtered through the air cleaner in the TBI unit. The air/fuel mixture is drawn through a clearance between the throttle valve and bore into the intake manifold. The intake manifold distributes the air/fuel mixture to each combustion chamber.