SsangYong Musso. Manual - part 105

1F-4 ENGINE CONTROLS

SSANGYONG  Y158

IGNITION SYSTEM OPERATION

This ignition system does not use a conventional distrib-
utor and coil. It uses a crankshaft position sensor input
to the Engine Control Module (ECM). The ECM then de-
termines Electronic Spark Timing (EST) and triggers the
electronic ignition system ignition coil.

This type of distributorless ignition system uses a “waste
spark” method of spark distribution. Each cylinder is
paired with the cylinder that is opposite it (2.3L DOHC:
2 - 3 or 1 - 4, 3.2L DOHC: 1 - 6 or 2 - 5 or 3 - 4). The
spark occurs simultaneously in the cylinder coming up
on the compression stroke and in the cylinder coming
up on the exhaust stroke. The cylinder on the exhaust
stroke requires very little of the available energy to fire
the spark plug. The remaining energy is available to the
spark plug in the cylinder on the compression stroke.

These systems use the EST signal from the ECM to
control the EST. The ECM uses the following informa-
tion:

Engine load (mass air flow sensor, manifold air pressure
sensor).

Engine coolant temperature.

Intake air temperature.

Crankshaft position.

Engine speed (rpm).

ELECTRONIC IGNITION SYSTEM
IGNITION COIL

The Electronic Ignition (EI) system ignition coil is located
on the cylinder head cover. The double ended coils re
ceive the signal for the ECM which controls the spark
advance.

Each EI system ignition coil provides the high voltage
to two spark plugs simultaneously;

2.3L DOHC

T1/1: cylinder 1 and 4

T1/2: cylinder 2 and 3

3.2L DOHC

T1/1: cylinder 2 and 5

T1/2: cylinder 3 and 4

T1/3: cylinder 1 and 6

The EI system ignition coil is not serviceable and must
be replaced as an assembly.

DESCRIPTION AND OPERATION

CRANKSHAFT POSITION SENSOR

This Electronic Ignition (EI) system uses inductive or
pick up type magnetic Crankshaft Position (CKP) sen-
sor.

The CKP sensor is located in the opposite side of the
crankshaft pulley and triggers the pick-up wheel teeth
which is equipped 60 - 2 teeth with a gab of 2 teeth at
360-degree spacing. This sensor protrudes through its
mount to within 1.1 ± 0.14 mm.

The output of the sensor is a sinusoidal signal. Each
tooth of the pick-up 60 - 2 wheel generates a positive
half wave. The ECM uses this sensor signal to generate
timed ignition and injection pulses that it sends to the
ignition coils and to the fuel injectors.

CAMSHAFT ACTUATOR

When the engine is running, the camshaft actuator ro-
tates the intake camshaft hydraulically and mechanically
relative to the camshaft sprocket by 32 ° crank angle to
the “advanced” position and back to the “retard” posi-
tion.

The camshaft actuator is actuated electro-mechanically
by the ECM. The positioning time of apporx. 1 second
is dependent on the engine oil pressure at the camshaft
actuator and on the oil viscosity and oil temperature,
respectively.

The camshaft indicator on the camshaft sprocket pro-
vides the camshaft rotational speed to the position sen-
sor as  an  input parameter for the engine ignition control
unit.

Operation Condition of Camshaft Actuator

Engine

RPM

Camshaft

position

Idle speed is

 improved

Blow-by gas is

decreased

Valve overlap is

decreased

Torque is increased

Fuel loss is decreased

NOx is decreased

Engine overrun is

prohibited

Effect

-

Retard

Retard

Advanced

Retard

Engine

stop

0 - 1,500

rpm

1,500 - 4,300

rpm

Above

4,300 rpm

ENGINE CONTROLS 1F-5

SSANGYONG  Y158

CAMSHAFT POSITION SENSOR

The Camshaft Position (CMP) sensor sends a CMP sig-
nal to the Engine Control Module (ECM). The ECM uses
this signal as a “synchronized pulse” to trigger the injec-
ors in the proper sequence. The ECM uses the CMP
signal to indicate the position of the #1 piston during its
power stroke. This allows the ECM to calculate true se-
quential fuel injection mode of operation. If the ECM de-
tects an incorrect CMP signal while the engine is running,
Diagnostic Trouble Code (DTC) P0341 will set.

FUEL CONTROL SYSTEM
OPERATION (2.3L DOHC)

The function of the fuel metering system is to deliver
the correct amount of fuel to the engine under all operating
conditions. The fuel is delivered to the engine by the in-
dividual fuel injectors mounted into the intake manifold
near each cylinder.

The main fuel control sensors are the Manifold Absolute
Pressure (MAP) sensor and the two heated oxygen
(O2S) sensors.

The MAP sensor measures or senses the intake manifold
vacuum. Under high fuel demands, the MAP sensor
reads a low vacuum condition, such as wide open
throttle. The Engine Control Module (ECM) uses this
information to enrich the mixture, thus increasing the
fuel injector on-time, to provide the correct amount of
fuel.  When decelerating, the vacuum increases. This
vacuum change is sensed by the MAP sensor and read
by the ECM, which then decreases the fuel injector on-
time due to the low fuel demand conditions.

The O2S 1 sensor is located in the exhaust manifold.
The other O2S 2 sensor is located in the exhaust pipe
after warm-up converter. The oxygen sensors indicate
to the ECM the amount of oxygen in the exhaust gas,
and the ECM changes the air/fuel ratio to the engine by
controlling the fuel injectors. The best air/ fuel ratio to
minimize exhaust emissions is 14.7 to 1, which allows
the catalytic converter to operate most efficiently.

Because of the constant measuring and adjusting of the
air/fuel ratio, the fuel injection system is called a “closed
loop” system.

The ECM uses voltage inputs from several sensors to
determine how much fuel to provide to the engine. The
fuel is delivered under one of several conditions, called
“modes.”

Starting Mode

When the ignition is turned ON, the ECM turns the fuel
pump relay on for 1 second. The fuel pump then builds
fuel pressure. The ECM also checks the Engine Coolant
Temperature (ECT) sensor and the Throttle Position (TP)
sensor and determines the proper air/fuel ratio for
starting the engine. This ranges from 1.5 to 1 at -36 ° C

(-33 ° F) coolant temperature to 14.7 to 1 at 94  ° C
 (201 ° F) coolant temperature. The ECM controls the
amount of fuel delivered in the starting mode by changing
how long the fuel injector is turned on and off. This is
done by “pulsing” the fuel injectors for very short times.

Run Mode

The run mode has two conditions called “open loop” and
“closed loop.”

Open Loop

When the engine is first started and it is above 690 rpm,
the system goes into “open loop” operation. In “open
loop,” the ECM ignores the signal from the O2S and
calculates the air/fuel ratio based on inputs from the
ECT sensor and the MAP sensor. The ECM stays in
“open loop” until the following conditions are met:

•••••

The O2S has a varying voltage output, showing that
it is hot enough to operate properly.

•••••

The ECT sensor is above a specified temperature
(22 °C).

•••••

A specific amount of time has elapsed after starting
the engine.

Closed Loop

The specific values for the above conditions vary with
different engines and are stored in the Electronically
Erasable Programmable Read-Only Memory (EE-
PROM). When these conditions are met, the system
goes into “closed loop” operation. In “closed loop,” the
ECM calculates the air/fuel ratio (fuel injector on-time)
based on the signals from the oxygen sensors. This
allows the air/fuel ratio to stay very close to 14.7 to 1.

Acceleration Mode

The ECM responds to rapid changes in throttle position
and airflow and provides extra fuel.

Deceleration Mode

The ECM responds to changes in throttle position and
airflow and reduces the amount of fuel. When decelera-
tion is  very fast, the ECM can cut off fuel completely for
short periods of time.

Battery Voltage Correction Mode

When battery voltage is low, the ECM can compensate
for a weak spark delivered by the ignition module by
using the following methods:

•••••

Increasing the fuel injector pulse width.

•••••

Increasing the idle speed rpm.

•••••

Increasing the ignition dwell time.

Fuel Cut-Off Mode

No fuel is delivered by the fuel injectors when the ignition
is off. This prevents dieseling or engine run-on. Also,
the fuel is not delivered if there are no reference pulses
received from the CKP sensor. This prevents flooding.

1F-6 ENGINE CONTROLS

SSANGYONG  Y158

FUEL CONTROL SYSTEM
OPERATION (3.2L DOHC)

The function of the fuel metering system is to deliver
the correct amount of fuel to the engine under all operating
conditions. The fuel is delivered to the engine by the in-
dividual fuel injectors mounted into the intake manifold
near each cylinder.

The main fuel control sensors are the Mass Air Flow
(MAF) sensor and the four heated oxygen (O2S)
sensors.

The MAF sensor monitors the mass flow of the air being
drawn into the engine. An electrically heated element is
mounted in the intake air stream, where it is cooled by
the flow of incoming air. Engine Control Module (ECM)
modulates the flow of heating current to maintain the
temperature differential between the heated film and the
intake air at a constant level. The amount of heating
current required to maintain the temperature thus
provides an index for the mass air flow. This concept
automatically compensates for variations in air density,
as this is one of the factors that determines the amount
of warmth  that the surrounding air absorbs from the
heated element.

MAF sensor is located between the air filter and  the
throttle valve. Under high fuel demands, the MAF sensor
reads a high mass flow condition, such as wide open
throttle. The Engine Control Module (ECM) uses this
information to enrich the mixture, thus increasing the
fuel injector ontime, to provide the correct amount of
fuel. When decelerating, the mass flow decreases. This
mass flow change is sensed by the MAF sensor and
read by the ECM, which then decreases the fuel injector
on-time due to the low fuel demand conditions.

The two O2S sensor are located in the exhaust man-
ifold. The other two O2S sensor are located in the
exhaust pipe after warm-up converter. The oxygen
sensors indicate to the ECM the amount of oxygen in
the exhaust gas, and the ECM changes the air/fuel ratio
to the engine by controlling the fuel injectors. The best
air/fuel ratio to minimize exhaust emissions is 14.7 to
1, which allows the catalytic converter to operate most
efficiently.

Because of the constant measuring and adjusting of the
air/fuel ratio, the fuel injection system is called a “closed
loop” system.

The ECM uses voltage inputs from several sensors to
determine how much fuel to provide to the engine. The
fuel is delivered under one of several conditions, called
“modes.”

Starting Mode

When the ignition is turned ON, the ECM turns the fuel
pump relay on for 1 second. The fuel pump then builds
fuel pressure. The ECM also checks the Engine Coolant
Temperature (ECT) sensor and the Throttle Position (TP)
sensor and determines the proper air/fuel ratio for

starting the engine. This ranges from 1.5 to 1 at -36 °C
(-33 °F) coolant temperature to 14.7 to 1 at 94 °C (201
°F) coolant temperature. The ECM controls the amount
of fuel delivered in the starting mode by changing how
long the fuel injector is turned on and off. This is done
by “pulsing” the fuel injectors for very short times.

Run Mode

The run mode has two conditions called “open loop” and
“closed loop.”

Open Loop

When the engine is first started and it is above 690 rpm,
the system goes into “open loop” operation. In “open
loop,” the ECM ignores the signal from the O2S and
calculates the air/fuel ratio based on inputs from the
ECT sensor and the MAF sensor. The ECM stays in
“open loop” until the following conditions are met:

•••••

The O2S has a varying voltage output, showing that
it is hot enough to operate properly.

•••••

The ECT sensor is above a specified temperature
(22 °C).

•••••

A specific amount of time has elapsed after starting
the engine.

Closed Loop

The specific values for the above conditions vary with
different engines and are stored in the Electronically
Erasable Programmable Read-Only Memory (EE-
PROM).

When these conditions are met, the system goes into
“closed loop” operation. In “closed loop,” the ECM
calculates the air/fuel ratio (fuel injector on-time) based
on the signals from the oxygen sensors. This allows
the air/fuel ratio to stay very close to 14.7 to 1.

Acceleration Mode

The ECM responds to rapid changes in throttle position
and airflow and provides extra fuel.

Deceleration Mode

The ECM responds to changes in throttle position and
airflow and reduces the amount of fuel. When decelera-
tion is very fast, the ECM can cut off fuel completely for
short periods of time.

Battery Voltage Correction Mode

When battery voltage is low, the ECM can compensate
for a weak spark delivered by the ignition module by us-
ing the following methods:

•••••

Increasing the fuel injector pulse width.

•••••

Increasing the idle speed rpm.

•••••

Increasing the ignition dwell time.

Fuel Cut-Off Mode

No fuel is delivered by the fuel injectors when the ignition
is off. This prevents dieseling or engine run-on. Also,
the fuel is not delivered if there are no reference pulses

ENGINE CONTROLS 1F-7

SSANGYONG  Y158

received from the CKP sensor. This prevents flooding.

EVAPORATIVE EMISSION
CONTROL  SYSTEM OPERATION

The basic Evaporative Emission (EVAP) control system
used is the charcoal canister storage method. This
method transfers fuel vapor from the fuel tank to an acti-
vated carbon (charcoal) storage canister which holds
the vapors when the vehicle is not operating. When the
engine is running, the fuel vapor is purged from the car-
bon element by intake airflow and consumed in the nor-
mal combustion process.

Gasoline vapors from the fuel tank flow into the tube la-
beled TANK. These vapors are absorbed into the car-
bon.

The canister is purged by Engine Control Module (ECM)
when the engine has been running for a specified amount
of time. Air is drawn into the canister and mixed with
the vapor. This mixture is then drawn into the intake
manifold.

The ECM supplies a ground to energize the EVAP emis-
sion canister purge solenoid valve. This valve is Pulse
Width Modulated (PWM) or turned ON and OFF several
times a second. The EVAP emission canister purge
PWM duty cycle varies according to operating condi-
tions determined by mass airflow, engine coolant tem-
perature, engine speed, vehicle speed, fuel trim, etc.

Poor idle, stalling, and poor driveability can be caused
by the following conditions:

•••••

An inoperative EVAP canister purge valve.

•••••

A damaged canister.

•••••

Hoses that are split, cracked, or not connected to
the proper tubes.

EVAPORATIVE EMISSION
CANISTER

The Evaporative Emission (EVAP) canister is an emis-
sion control device containing activated charcoal gran-
ules. The evaporative emission canister is used to store
fuel vapors from the fuel tank. Once certain conditions
are met, the Engine Control Module (ECM) activates
the  EVAP canister purge solenoid, allowing the fuel
vapors to  be  drawn into the engine cylinders and burned.

POSITIVE CRANKCASE
VENTILATION CONTROL SYSTEM
OPERATION

A Positive Crankcase Ventilation (PCV) control system
is used to provide complete use of the crankcase va-
pors. Fresh air from the air cleaner is supplied to the

crankcase. The fresh air is mixed with blow-by gases
which then pass through a vacuum hose into the intake
manifold.

Periodically inspect the hoses and the clamps. Replace
any crankcase ventilation components as required.

A restricted or plugged PCV hose may cause the follow-
ing conditions:

•••••

Rough idle

•••••

Stalling or low idle speed

•••••

Oil leaks

•••••

Oil in the air cleaner

•••••

Sludge in the engine

A leaking PCV hose may cause the following conditions:

•••••

Rough idle

•••••

Stalling

•••••

High idle speed

ENGINE COOLANT TEMPERATURE
SENSOR

The Engine Coolant Temperature (ECT) sensor is a
thermistor (a resistor which changes value based on
temperature) mounted in the engine coolant stream.

Low coolant temperature produces a high resistance
(2449.9 ± 159.1 at 20 ° C [68 ° F]) while high tempera-
ture causes low resistance (112.9 ± 7.2 at 120 ° C [248
°F]).

The Engine Control Module (ECM) supplies 5 volts to
the ECT sensor through a resistor in the ECM and mea-
sures the change in voltage. The voltage will be high
when the engine is cold and low when the engine is hot.

By measuring the change in voltage, the ECM can de-
termine the coolant temperature. The engine coolant
temperature affects most of the systems that the ECM
controls. A failure in the ECT sensor circuit should set
a Diagnostic Trouble Code (DTC) P0116, P0117 or
P0118. Remember, these DTCs indicate a failure in the
ECT circuit, so proper use of the chart will lead either to
repairing a wiring problem or to replacing the sensor to
repair a problem properly.

THROTTLE VALVE ACTUATOR

The throttle actuator is actuated by the ECM according
to the position of the accelerator pedal position.

It has two potentiometers which signal the position of
the throttle valve to the ECM to enable it to recognize
the various engine load states.

Ignition “Off”

In the de-energized states the throttle valve position is
determined to be spring capsule.