SsangYong Musso. Manual - part 322

1F1-46  M162 ENGINE CONTROLS

1 Vacuum Hose
2 Circlip
3 Fuel Pressure Regulator

FUEL PRESSURE REGULATOR

4 O-ring ..................................................... replace
5 O-ring ..................................................... replace

M162 ENGINE CONTROLS  1F1-47

3. Disconnect the vacuum hose.

4. Disconnect the circlip and remove the fuel pressure

regulator.

5. Apply the oil to O-ring lightly and then replace it.

6. Installation should follow the removal procedure in the

reverse order.

7. Check for fuel pressure and internal leaks by operating the

engine.

2. Discharge the pressure in fuel supply system by pressing

the service valve.

Removal & Installation Procedure

1. Remove the fuel pressure test connector.

1F1-48  M162 ENGINE CONTROLS

A. Valves  Closed
B. Valves Opened

The pressure difference between the fuel pressure and the
intake manifold is about 3.8 bars during the full load.

<Operating at Idle and partial load>

The spring chamber(9) is connected to the intake manifold
with the vacuum hose at the intake pipe connection(7).  The
negative pressure generated in the intake manifold activates
the diaphragm, and thus the fuel pressure gets reduced to the
rate of the operating extent of the diaphragm by the intake
manifold's negative pressure.

Consequently, the fuel pressure in the fuel distributor changes
by the intake manifold's negative pressure, and the injector's
fuel pressure gets reduced independently to the throttle valve's
position. Thus, the fuel injection volume can only be determined
according to the injector's injecting duration.

2. Fuel return line
3. Valve
5. Diaphragm
6. Compression Spring
8. Fuel Chamber
9. Spring Chamber

1. Fuel Pressure Regulator
2. Intake Manifold
3. Fuel Return(to fuel tank)
4. Fuel Supply(form fuel pump)
5. Fuel Pressure(approx. 3.8 bars)
6. Intake Manifold Negative Pressure(0 bar)

Function of the Fuel Pressure Regulator

The fuel pressure regulator maintains the fuel pressure in the
fuel line with the pressure of 3.2 bars to 3.8 bars according to
the intake manifold pressure.  This operating pressure cannot
be changed, and the fuel injection volume will be only
determined by the injection time. Over supplied fuel returns to
the fuel tank through the return line.

<Operating at full load>

There is no negative pressure applied to the spring chamber(9)
during the full load, and it is separated from the fuel chamber(8)
by the diaphragm(5).

When the fuel pressure goes up, the diaphragm forces the
compression spring(6) in the direction of compression .  At this
moment, the valve(3) sticks to the diaphragm by the fuel
pressure, and the fuel return line(2) opens. The fuel over
supplied returns to the fuel tank through the return line.

M162 ENGINE CONTROLS  1F1-49

The pressure difference between the fuel pressure and
the intake manifold is approx. 3.2 bars during idling.

<Fuel Pressure Diagram>

1. Fuel Pressure Regulator
2. Intake Manifold
3. Fuel Return(to fuel tank)
4. Fuel Supply(from fuel pump)
7. Fuel Pressure(approx. 3.2 bars)
8. Intake Manifold Negative Pressure(0.6 bars)

A. Fuel pressure
B. Intake Manifold Negative Pressure
LL. Idling
TL. Partial load
VL. Full load