Hyundai Sonata 1991 Shop Manual page 240

MPI SYSTEM
MPI SYSTEM
GENERAL INFORMATION
Y310AOA
The airIfuel ratio is controlled by varying the driving time of each injector.
After passing through the in-tank filter, fuel is force-fed by the in-tank fuel pump delivery pipe through the fuel
filter, and is distributed to each injector by the delivery pipe. The fuel pressur" applied to the injector is maintained
at a fixed level by the fuel pressure regulator so that it may be higher that the internal pressure of the intake
manifold where fuel injection takes place. After pressure regulation, excess fuel is returned to the fuel tank through
the return hose. When the injector is energized, the valve inside the injector opens fully to inject the fuel.
The injectors inspect fuel to each manifold port, in the sequential firing order of each cylinder, according to ECU
signals.
31YQOl
~~--Fuel
injector
~====-
.l-''---''"'-l.Fuel pressure regulator
To fuel tank
-
ECU
Ignition switch-5T terminal
Motor position sensor (MPS)
Oxygen sensor
Atmospheric pressure sensor
Intake air temperature sensor
Coolant temperature sensor
Throttle position sensor (TPS)
Idle switch
No.1 cylinder TDC sensor
Air flow sensor (AFSI
Crank angle sensor:
Fuel tank
31YOO2
- -
:r-"'-='-'i
Delivery pipe
31-15