Fuel Injection System - Husqvarna TC 450 Workshop Manual

2
a
3
2
c
d
b
d

FUEL INJECTION SYSTEM

1
The fuel injection system consists of: fuel tank (1), electric pump (2), hose (3)
and injector (4). The fuel in the tank is pumped by the fuel pump and the pres-
surized fuel flows into the injector installed in the throttle body (6). The fuel is
injected into the throttle body with a conical dispersion when the injector opens
according to the injection signal coming from the Electronic power unit (5) located
b
under the fuel tank.
The items to be considered for the correct output of the fuel in every condition
of use of the vehicle are the followings:
- Air temperature in the intake manifold;
- Engine coolant temperature;
- Atmospheric pressure in the intake manifold (in the current position and alti-
tude);
- Throttle opening percentage;
- SMR: Vehicle rollover;
- Rich or lean combustion mixture (O2 sensor);
4
- Battery voltage;
- Sensors source;
6
- Current gear position;
- Pulse width of fuel injector;
- Ignition coil;
- O2 heater.
The diagnostic software "DIAGNOSIS SOFTWARE KIT" (see on pages S.3-S.4)
allows the check of the above mentioned parts in case of fuel injection system
malfunction.
The electric pump (2) is assembled in the bottom of the fuel tank (1) and consists
of rotor, magnet, impeller, brushes, control valve and relief valve. The ECU (5)
checks ON/OFF condition of the pump.
In order to remove the fuel pump, first it is necessary to remove the fuel tank
as shown on page E.23, then remove the six fastening screws (a); for the re-
assembly, reverse the above mentioned operations (for the fuel pump check,
please see page S.5).
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b
c
FUEL INJECTION SYSTEM
c
S.2
a- Fuel pump fastening screw
b- Delivery union
c- Pump filter
d- Fuel filter
Part. N. 8000 H1344 (10-2009)