Page 634 of 1463
1F1-64 M162 ENGINE CONTROLS
VACUUM SYSTEM
1 Purge Control Valve
2 Molded Hose
3 Insulator
4 Fuel Tube
5 Molded Hose
6 Idle Regulator
7 Resonance Flap
8 Intake Manifold
9 Fuel Pressure Regulator10 Vacuum Line Rubber Hose
11 Vacuum Tube(Gray, 270mm)
12 Molded Hose
13 Rubber Cap
18 Rubber Hose
19 Vacuum Tube(Brown or Black, 770mm)
20 Rubber Hose
A To Canicter
Page 650 of 1463

SECTION 1F2
M161 ENGINE CONTROLS
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 . . . . . . . . . . . . . . . . . . . . . . . 1F2-2
Fastener Tightening Specifications . . . . . . . . 1F2-2
Special Tools . . . . . . . . . . . . . . . . . . . . . . . 1F2-3
Special Tools Table . . . . . . . . . . . . . . . . . . . . 1F2-3
Schematic and Routing Diagrams . . . . . . . 1F2-4
E23 ECU (MSE) . . . . . . . . . . . . . . . . . . . . . . 1F2-4
E23 ECU (HFM) . . . . . . . . . . . . . . . . . . . . . . 1F2-5
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . 1F2-6
Self Diagnosis Socket Pin Numbers and
Descriptions . . . . . . . . . . . . . . . . . . . . . . . . 1F2-6
Self Diagnosis Failure Code (for E23 ENG) . 1F2-7
Test Box Connection . . . . . . . . . . . . . . . . . . 1F2-10
Fuel Injection System Test . . . . . . . . . . . . . 1F2-11
Ignition System Test . . . . . . . . . . . . . . . . . . 1F2-20
Idling Control and Electronic Pedal
System Test . . . . . . . . . . . . . . . . . . . . . . . 1F2-25
Air Conditioner Control System Test . . . . . . 1F2-27
Fuel Pressure and Internal Leakage Test . . 1F2-28
Fuel Pump Test . . . . . . . . . . . . . . . . . . . . . . 1F2-30Injector Test . . . . . . . . . . . . . . . . . . . . . . . . 1F2-32
Maintenance and Repair . . . . . . . . . . . . . 1F2-34
On-Vehicle Service . . . . . . . . . . . . . . . . . . . . 1F2-34
ECU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1F2-34
Fuel Pressure Regulator . . . . . . . . . . . . . . 1F2-45
Fuel Distributor . . . . . . . . . . . . . . . . . . . . . . 1F2-49
Injector . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1F2-54
Fuel Filter . . . . . . . . . . . . . . . . . . . . . . . . . . 1F2-57
Fuel Pump . . . . . . . . . . . . . . . . . . . . . . . . . 1F2-58
Purge Switchover Valve . . . . . . . . . . . . . . . 1F2-62
Vacuum System . . . . . . . . . . . . . . . . . . . . . 1F2-64
Crankshaft Position Sensor . . . . . . . . . . . . 1F2-66
Camshaft Position Sensor . . . . . . . . . . . . . 1F2-68
Hot Film Air Mass (HFM) Sensor . . . . . . . . . 1F2-70
Oxygen Sensor . . . . . . . . . . . . . . . . . . . . . . 1F2-73
Knock Sensor . . . . . . . . . . . . . . . . . . . . . . . 1F2-75
Coolant Temperature Sensor . . . . . . . . . . . 1F2-76
Accelerator Pedal Module . . . . . . . . . . . . . . 1F2-79
Page 666 of 1463

M161 ENGINE CONTROLS 1F2-17
Failure
codeItem
Þ 15.1
Checking method Test
stepRequirement
Specified
valuePossible cause
73 28 - 12 W
· ·· ·
· Camshaft
actuator:
Solenoid
resistance
(E23 only)
Þ 18.0· ·· ·
· Purge
control
valve:
- Vacuum
control· Engine:in idling/
normal operating
temperature· Power supply cable
· OVPR
· Cable
· Camshaft actuatorDiagnosis
socket
Þ 16.0
73 69Engine is
unstable or
stopped.· ·· ·
· Camshaft
actuator:
Mechanical
actuation
(E23 only)· Mechanical failure
of camshaft
actuator
Þ 17.0
· Engine:in idling
34 11The purge
control valve
should be
operated after
approx.
1minute.
(refer to figure
5)· ·· ·
· Purge
control
valve:
- Operating
226,
227,
· ECU
· Cable
· Purge control valve
· Ignition:ON0.2 - 0.4 A - Current
consumption
10 34
Creating above
50mbar of
vacuum after
approx.
1 minute
Þ 19.0
· Ignition:OFF
38 37· Data bus
· Þ 19.1
· Þ 19.2 55 - 65 W
· ·· ·
· CAN data
bus
· Ignition:OFF
· Engine:in idling
40,
41,
54,
40,
41,
54,Connect the vacuum
gauge between the
control valve and
canister
22,23,
24,26,
27,29,
30,31,
59,60,
Page 678 of 1463

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
Page 694 of 1463
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
Page 695 of 1463
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.
Page 696 of 1463

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.
Page 698 of 1463
M161 ENGINE CONTROLS 1F2-49
FUEL DISTRIBUTOR
Preceding Work : Removal of intake air duct
1 Fuel Distributor
2 Circlip
3 Fuel Pressure Regulator
4 O-ring
5 Fuel Pressure Test Connector
6 Seal Ring
7 Vacuum Hose
8 Combination Bolt (M8 X 120).........22.5-27.5 Nm9 Fuel Return Line
10 Seal Ring
11 Hollow Bolt.....................................22.5-27.5 Nm
1 2 Clamp
13 Bolt (M8 X 22)........................................ 9-11 Nm
14 Injector Bracket
15 Injector
16 O-ring