1998 SSANGYONG MUSSO fuel pressure

1F2-2 M161 ENGINE CONTROLS
SPECIFICATIONS
FASTENER TIGHTENING SPECIFICATIONS
Application
Fuel Return and Supply Line
Fuel Distributor Assembly Bolt
Pressure Test Connector
Fuel Inlet and Outlet Line
Fuel Filter Mounting Bracket Bolt
Crankshaft Position Sensor Bolt
Camkshaft Position Sensor Bolt
Knock Sensor Mounting Bolt
Coolant Temperature BoltN·m
25 - 30
22.5 - 27.5
21.6 - 26.4
25 - 30
4 - 8
9 - 11
9 - 11
22.5 - 27.5
18 - 22

1F2-28 M161 ENGINE CONTROLS
FUEL PRESSURE AND INTERNAL LEAKAGE TEST
01 Pressure Tester
02 Pressure Hose
03 Measuring Beaker
Preparation
Connection of the Equipment
1. Turn the ignition switch to "OFF" position.
2. Remove the air cleaner cross pipe.
3. Remove the cap on fuel pressure test plug and connect the
pressure hose and pressure tester.
4. Prepare the beaker for measuring the amount of fuel.
Tools Required
103 589 00 21 00 Pressure Tester
119 589 04 63 00 Pressure Hose

M161 ENGINE CONTROLS 1F2-29
Failure
codeItemChecking method Te s t
stepRequirementSpecified
valuePossible cause
3.2 - 3.6 bar· ·· ·
· Fuel
pressure:in
idling speed
- When the
vacuum is
applied· Engine:in idling
- Colse the valve
screw on pressure
testerÞ 1.0 Connect the fuel
pressure test plug to
the pressure tester
(refer to the flgure on
previous page).· Þ Fuel pump test
· Fuel pressure
regulator
3.7 - 4.2 bar
· ·· ·
· Fuel
pressure:in
idling speed
- When the
vacuum is
not applied· Engine:in idling
- Colse the valve
screw on pressure
tester Þ 2.0 Connect the fuel
pressure test plug to
the pressure tester
(refer to the flgure on
previous page).· Þ Fuel pump test
· Fuel pressure
regulator
> 3.0 bar
· ·· ·
· Fuel system
internal
leakage:· Engine:stop Þ 3.0 Connect the fuel
pressure test plug to
the pressure tester
(refer to the flgure on
previous page).· The pressure drops
rapidly:non-return
valve in fuel pump
> 2.5 bar· After 30 minutes
from engine stop· The pressure
drops slowly:
- Injector test
- Fuel pressure
regulator
- O-ring

1F2-30 M161 ENGINE CONTROLS
FUEL PUMP TEST
Preparation
1 ECU
2 Test Coupling(No.1-60)
3 Test Coupling(No.61-120)
4 Stop Watch
5 Measuring Beaker
Connection of the Equipment
1. Turn the ignition switch to "OFF" position.
2. Connect the test box to the ECU.0 3 Test Box
04 ECU Test Cable
Tools Required
103 589 00 21 00 Pressure Tester
210 589 00 99 00 Adaptor Line
129 589 00 21 00 Test Box
210 589 08 63 00 Ecu Test Cable

M161 ENGINE CONTROLS 1F2-45
1 Vacuum Hose
2 Circlip
3 Fuel Pressure Regulator
FUEL PRESSURE REGULATOR
4 O-ring ..................................................... replace
5 O-ring ..................................................... replace

1F2-46 M161 ENGINE CONTROLS
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.

M161 ENGINE CONTROLS 1F2-47
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.

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.

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.

1F2-48 M161 ENGINE CONTROLS
The pressure difference between the fuel pressure and
the intake manifold is approx. 3.2 bars during idling.

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