Page 722 of 1463
M161 ENGINE CONTROLS 1F2-73
OXYGEN SENSOR
1 Electricity Wire
2 Oxygen Sensor Housing
3 Sensor Ceramic
4 Electrode (Internal)
5 Electrode (External)
6 Heating Coil
7 Open Space
8 Protector Tube
Functions
The oxygen sensor optimizes the combustion (Air-Fuel Ratio
14.7:1) and resets the Air-fuel ratio in the ECU after sensing
the amount of oxygen from the exhaust gases to diminish the
exhaust gases.
- Rich(<1) above approx. 450mV
- Lean(>1) below approx. 450mV
Locatoin of Sensor
Oxygen sensor is located on the front exhaust pipe.
Page 730 of 1463

SECTION 1F3
OM600 ENGINE CONTROLS
Specifications . . . . . . . . . . . . . . . . . . . . . . . 1F3-1
Fastener Tightening Specifications . . . . . . . . 1F3-1
Maintenance and Repair . . . . . . . . . . . . . . 1F3-2
On-Vehicle Service . . . . . . . . . . . . . . . . . . . . 1F3-2
Fuel System . . . . . . . . . . . . . . . . . . . . . . . . . 1F3-2
Fuel Injection Pump Coding . . . . . . . . . . . . . 1F3-3
Fuel Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . 1F3-4
Vacuum Control System Test . . . . . . . . . . . . 1F3-5
Vacuum Pump(Sectional View) . . . . . . . . . . 1F3-10
Vacuum Pump Test . . . . . . . . . . . . . . . . . . . 1F3-11
Vacuum Pump . . . . . . . . . . . . . . . . . . . . . . 1F3-13
Vacuum Unit Replacement . . . . . . . . . . . . . 1F3-15Idle Speed Adjustment . . . . . . . . . . . . . . . . 1F3-16
Fuel Pump Test . . . . . . . . . . . . . . . . . . . . . . 1F3-18
Fuel Pump . . . . . . . . . . . . . . . . . . . . . . . . . 1F3-21
Injection Nozzle Test . . . . . . . . . . . . . . . . . . 1F3-22
Injection Nozzles . . . . . . . . . . . . . . . . . . . . . 1F3-25
Injection Nozzle Repair . . . . . . . . . . . . . . . . 1F3-27
Removal and Installation of
Injection Timing Device . . . . . . . . . . . . . . 1F3-30
Injection Timing Device . . . . . . . . . . . . . . . . 1F3-35
Start of Delivery Test
(Position Sensor, RIV Method) . . . . . . . . . 1F3-37
Fuel Injection Pump . . . . . . . . . . . . . . . . . . 1F3-46
TABLE OF CONTENTS
Caution: Disconnect the negative battery cable before removing or installing any electrical unit or when a
tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable
will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise
noted.
SPECIFICATIONS
FASTENER TIGHTENING SPECIFICATIONS
Application
Fuel Tank Mounting Nut
Fuel Pump Pressure Line
Fuel Injection Nozzle
Fuel Injection Pipe
Nozzle Tensioning Nut
Screw Plug
Left-Hand Thread BoltN·m
28 - 47
13
35 - 40
18
80
30
46
Page 731 of 1463
1F3-2 OM600 ENGINE CONTROLS
FUEL SYSTEM
1 Fuel Injection Pump
2 Fuel Feed Pump
3 Overflow Valve
4 Injection Nozzle
5 Pre-filter6 Fuel Return Hose
7 Injection Line
8 Fuel Tank
9 Fuel Filter
10 Choke Orifice
MAINTENANCE AND REPAIR
ON-VEHICLE SERVICE
Page 732 of 1463
OM600 ENGINE CONTROLS 1F3-3
FUEL INJECTION PUMP CODING
Model Code
PES 4M 55C 320 RS 167
PES 5M 55C 320 RS 168
Fuel Injection Pump Code
Example)PES 5M 55C 320 RS 168
P Pump
E Self-Driven
S End Flange Mounting
5 Number of Cylinders (5EA)
M Pump Size
55 Element Diameter
C Modification Letter
320 Assembly Number
R Direction of Rotation (clockwise)
S188 Special Version
RSF Governor
R Governor
S Coil Spring
F Drive Governor
Component Location
1. Fuel Injection Pump
2. Vacuum Unit (Stop Unit)
3. Control Lever
4. PLA Vacuum Unit (Idle Speed Adjustment)
5. Governor
6. Fuel Pump
OM661 LA Engine
OM662 LA Engine
Page 733 of 1463
1F3-4 OM600 ENGINE CONTROLS
FUEL TANK
1 Fuel Tank
2 The Sender of Fuel Tank
3 2-way Check Valve
4 Pre Filter
5 Front Fuel Filler Neck
6 Rear Fuel Filler Neck
7 Fuel Supply Tube8 Fuel Return Tube
9 Filter Hose
10 Fuel Tank Hose
11 Fuel Filler Cap
1 2 Clip
1 3 Clip
Page 734 of 1463
OM600 ENGINE CONTROLS 1F3-5
VACUUM CONTROL SYSTEM TEST
2 Engine Cut-Off Valve (Ignition Key Switch)
3 Auto-locking Hub Solenoid Valve
4 Engine Stop Valve Unit
5 PLA Vacuum Unit (Idle Speed Adjustment)
6 Engine
7 Vacuum Pump8 30° Thermovalve
9 Fuel Injection Pump
10 Filter with Restriction
11 Check Valve
12 Modulating Pressure Line (Automatic T/M)
Test Data
Idle Speed Increase
Permissible Pressure Drop of SystemAt least 100 rpm at approx. 500mbr
400 - 500mbar approx. 1 min.
Page 740 of 1463
OM600 ENGINE CONTROLS 1F3-11
VACUUM PUMP TEST
1 Fuel Filter
2 Vacuum Line3 Ancillaries Connection
4 Vacuum Tester
Tools Required
201 589 13 21 00 Vacuum Tester
Page 741 of 1463
1F3-12 OM600 ENGINE CONTROLS
Test Procedure
1. Remove the fuel filter (1) and keep the filter not to be
damaged from running engine.
2. Remove the vacuum line (2) from ancillaries connection (3).
3. Connect the vacuum tester (4) to the ancillaries connection
(3).
Vacuum Tester 201 589 13 21 00
4 Run the engine at idle and check vacuum pressure after 30
sec.
Notice
If out of standard, replace the vacuum pump.
5. Remove the vacuum tester.
6. Connect the vacuum line to the ancillaries connection.
7. Install the fuel filter.
Standard > 70 mbar