Fuel System Outline; Fuel System Testing And Diagnosis - Subaru EH72 FI Service Information

6-2-4 WIRE HARNESS
The wire harness for the FI system connects key system components to the ECU .
The FI wire harness contains a temperature sensor that measures engine temperature, and
connects fuel injectors, ignition coils, electric fuel pump, pressure switch, and warning lamp .
The ECU uses this input to adjust to engine various conditions and monitors for failure diagnosis .
6-2-5 CHOKE SYSTEM
The throttle body monitors air pressure and engine temperature at start up and performs the
choke function automatically .
The choke system automatically adjusts for easier start of the engine in all weather conditions .

6-3 FUEL SYSTEM OUTLINE

Muffler
TANK

6-4 FUEL SYSTEM TESTING AND DIAGNOSIS

Most fuel system malfunctions occur when the fuel/air ratio of the mixture is not correct .
This is usually caused by clogged fuel filters, air passages, fuel passages, or by variations in
the fuel level .
To get the best possible performance from the throttle body, make sure that the fuel feed and
air feed passages are free so air and fuel can flow freely through them .
The procedure for inspecting the fuel system is described below .
Run all system tests with a full tank of fresh, clean fuel .
Fuel Pressure Regulator
M.A.P. Sensor
Magneto
Ignition
Unit
Ignition Pulse
FILTER PIPE
FUEL RETURN PIPE
Throttle Body Assy
Fuel Injector
ECU
PULSATION
DAMPER
Engine
Temperature
sensor
FUEL PULSATION
PUMP DAMPER
- 17 -
Air
Cleaner
Fuel
Filter
Fuel Tank
Fuel
Pump
FUEL
COMBUSION
INJECTION