Aeon 350cc, Service Manual

Page: 111 / 192

ELECTRONIC FUEL INJECTION
5-111
2. Connect the pressure hose of the fuel pressure gauge to the
fuel pump discharge cock.
Connect the clear hose into fuel pump inlet and another side to
a portable gasoline container or the equipment fuel tank.
3. Turn on the key switch to activate the pump and check the
system pressure on the gauge. If system pressure of 3 bar/ 43.5
psi is observed, the ignition switch, ECU, fuel pump, and
pressure regulator are working properly. Turn the key switch
off and depress the valve button on the tester to relieve the
system pressure.
Normal Fuel Pressure: 3 Bar (300kpa)/ 43.5 psi.
4. If the pump did not activate, disconnect the harness
connector from the fuel pump. Connect a DC voltmeter across
terminals “A” and “B” in the plug on the vehicle harness side.
Turn on the key switch and observe voltage to ensure a
minimum of 10 volts is present.
NOTE: If the voltage was below 10 VDC, test the
battery, ignition switch, relay(s), wiring harness and
ECU.
FUEL PRESSURE REGULATOR OPERATION
OVERVIEW
The fuel pressure regulator maintains the required operating
system pressure of 3.0 bar. A rubber-fiber diaphragm divides
the regulator into two separate sections; the fuel chamber and
the pressure regulating chamber. The pressure regulating
spring presses against the valve holder (part of the diaphragm),
pressing the valve against the valve seat. The combination of
atmospheric pressure and regulating spring tension equals the
desired operating pressure. Any time the fuel pressure against
the bottom of the diaphragm exceeds the desired (top)
pressure; the valve opens, relieving the excess pressure,
returning the excess fuel back to the tank.
FUEL PRESSURE REGULATOR TEST
Refer to the “Fuel Pump Test” procedure.
FUEL PRESSURE REGULATOR
REPLACEMENT
The pressure regulator is a sealed, non-serviceable assembly. If
it is faulty, the fuel pressure regulator must be replaced.
TPS OPERATION OVERVIEW
The throttle position sensor (TPS) is used to indicate throttle
plate angle to the ECU.
Mounted on the throttle body and operated directly off the end
of the throttle shaft, the TPS works like a rheostat, varying the
voltage signal to the ECU in direct correlation to the angle of
the throttle plate. This signal is processed by the ECU and
compared to the internal pre-programmed maps to determine
the required fuel and ignition settings for the amount of engine
load.
TPS TEST PROCEDURE
The throttle position sensor (TPS) is a non-serviceable item. If
it is faulty, it must be replaced. It can be tested using the
following method:
NOTE: Before proceeding with any of the following
measurements or tests, it’s extremely important to
verify the throttle body bore is clean of any carbon
build-up. Remove the intake boot and inspect the
throttle body bore. If required, remove the throttle
body and clean the bore-using carburetor cleaner.
ENGINE COOLANT TEMPERATURE SENSOR