Opel Frontera UBS. Manual - part 2192

 

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Opel Frontera UBS. Manual - part 2192

 

 

6E–341

ENGINE DRIVEABILITY AND EMISSIONS

this is done, if the problem still exists, it may be diagnosed
in the normal manner.

Electrostatic Discharge Damage

Electronic components used in the PCM are often
designed to carry very low voltage.  Electronic
components are susceptible to damage caused by
electrostatic discharge.  Less than 100 volts of static
electricity can cause damage to some electronic
components.  By comparison, it takes as much as 4000
volts for a person to feel even the zap of a static
discharge.

TS23793

There are several ways for a person to become statically
charged.  The most common methods of charging are by
friction and induction.

D

An example of charging by friction is a person sliding
across a vehicle seat.

D

Charge by induction occurs when a person with well
insulated shoes stands near a highly charged object
and momentary touches ground.  Charges of the
same polarity are drained off leaving the person
highly charged with the opposite polarity.  Static
charges can cause damage, therefore it is important
to use care when handling and testing electronic
components.

NOTE: To prevent possible electrostatic discharge
damage, follow these guidelines:

D

Do not touch the PCM connector pins or soldered
components on the PCM circuit board.

D

Do not touch the knock sensor module component
leads.

D

Do not open the replacement part package until the
part is ready to be installed.

D

Before removing the part from the package, ground
the package to a known good ground on the vehicle.

D

If the part has been handled while sliding across the
seat, while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.

Upshift Lamp

Refer to 

Manual Transmission.

General Description (Air Induction)

Air Induction System

The air induction system filters contaminants from the
outside air, and directs the progress of the air as it is
drawn into the engine.  A remote-mounted air cleaner
prevents dirt and debris in the air from entering the
engine.  The air duct assembly routes filtered air to the
throttle body.  Air enters the engine by to following steps:
1. Through the throttle body.
2. Into the common chamber.
3. Through the cylinder head intake ports.
4. Into the cylinders.

055RV010

General Description (Fuel Metering)

Acceleration Mode

The PCM provides extra fuel when it detects a rapid
increase in the throttle position and the air flow.

Accelerator Controls

The accelerator control system is a cable-type system
with specific linkage adjustments.
Refer to 

Cable Adjustment.

Battery Voltage Correction Mode

When battery voltage is low, the PCM will compensate for
the weak spark by increasing the following:

D

The amount of fuel delivered.

D

The idle RPM.

D

Ignition dwell time.

CMP Signal

The PCM uses this signal to determine the position of the
number 1 piston during its power stroke, allowing the

6E–342

ENGINE DRIVEABILITY AND EMISSIONS

PCM to calculate true sequential multiport fuel injection
(SFI).  Loss of this signal will set a DTC P0341.  If the CMP
signal is lost while the engine is running, the fuel injection
system will shift to a calculated sequential fuel injection
based on the last fuel injection pulse, and the engine will
continue to run.  The engine can be restarted and will run
in the calculated sequential mode as long as the fault is
present, with a 1-in-6 chance of being correct.

Clear Flood Mode

Clear a flooded engine by pushing the accelerator pedal
down all the way.  The PCM then de-energizes the fuel
injectors.  The PCM holds the fuel injectors de-energized
as long as the throttle remains above 80% and the engine
speed is below 800 RPM.  If the throttle position becomes
less than 80%, the PCM again begins to pulse the
injectors “ON” and “OFF,” allowing fuel into the cylinders.

Deceleration Mode

The PCM reduces the amount of fuel injected when it
detects a decrease in the throttle position and the air flow.
When deceleration is very fast, the PCM may cut off fuel
completely for short periods.

Engine Speed/Vehicle Speed/Fuel Disable
Mode

The PCM monitors engine speed.  It turns off the fuel
injectors when the engine speed increase above 6400
RPM. The fuel injectors are turned back on when engine
speed decreases below 6150 RPM.

Fuel Cutoff Mode

No fuel is delivered by the fuel injectors when the ignition
is “OFF.”  This prevents engine run-on.  In addition, the
PCM suspends fuel delivery if no reference pulses are
detected (engine not running) to prevent engine flooding.

Fuel Injector

The sequential multiport fuel injection (SFI) fuel injector is
a solenoid-operated device controlled by the PCM. The
PCM energizes the solenoid, which opens a valve to allow
fuel delivery.
The fuel is injected under pressure in a conical spray
pattern at the opening of the intake valve. Excess fuel not
used by the injectors passes through the fuel pressure
regulator before being returned to the fuel tank.
A fuel injector which is stuck partly open will cause a loss
of fuel pressure after engine shut down, causing long
crank times.

0003

Fuel Metering System Components

The fuel metering system is made up of the following
parts:

D

The fuel injectors.

D

The throttle body.

D

The fuel rail.

D

The fuel pressure regulator.

D

The PCM.

D

The crankshaft position (CKP) sensor.

D

The camshaft position (CMP) sensor.

D

The idle air control (IAC) valve.

D

The fuel pump.

D

The fuel pump relay.

Basic System Operation
The fuel metering system starts with the fuel in the fuel
tank.  An electric fuel pump, located in the fuel tank,
pumps fuel to the fuel rail through an in-line fuel filter.  The
pump is designed to provide fuel at a pressure above the
pressure needed by the injectors.  A fuel pressure
regulator in the fuel rail keeps fuel available to the fuel
injectors at a constant pressure.  A return line delivers
unused fuel back to the fuel tank.  Refer to 

Section 6C for

further information on the fuel tank, line filter, and fuel
pipes.

Fuel Metering System Purpose

The basic function of the air/fuel metering system is to
control the air/fuel delivery to the engine.  Fuel is delivered
to the engine by individual fuel injectors mounted in the
intake manifold near each intake valve.
The main control sensor is the heated oxygen sensor
(HO2S) located in the exhaust system.  The HO2S tells
the PCM how much oxygen is in the exhaust gas.  The
PCM changes the air/fuel ratio to the engine by controlling
the amount of time that fuel injector is “ON.”  The best
mixture to minimize exhaust emissions is 14.7 parts of air
to 1 part of gasoline by weight, which allows the catalytic
converter to operate most efficiently.  Because of the

6E–343

ENGINE DRIVEABILITY AND EMISSIONS

constant measuring and adjusting of the air/fuel ratio, the
fuel injection system is called a “closed loop” system.
The PCM monitors signals from several sensors in order
to determine the fuel needs of the engine. Fuel is
delivered under one of several conditions called “modes.”
All modes are controlled by the PCM.

Fuel Pressure Regulator

The fuel pressure regulator is a diaphragm-operated
relief valve mounted on the fuel rail with fuel pump
pressure on one side and manifold pressure on the other
side.  The fuel pressure regulator maintains the fuel
pressure available to the injector at three times
barometric pressure adjusted for engine load.  It may be
serviced separate.
If the pressure is too low, poor performance and a DTC
P0131, DTC P0151,DTC P0171 or DTC P1171 will be the
result.  If the pressure is too high, excessive odor and/or a
DTC P0132, DTC P0152,DTC P0172 or DTC P0175 will
be the result.  Refer to 

Fuel System Diagnosis for

information on diagnosing fuel pressure conditions.

0011

Fuel Pump Electrical Circuit

When the key is first turned “ON,” the PCM energizes the
fuel pump relay for two seconds to build up the fuel
pressure quickly.  If the engine is not started within two
seconds, the PCM shuts the fuel pump off and waits until
the engine is cranked.  When the engine is cranked and
the 58 X crankshaft position signal has been detected by
the PCM, the PCM supplies 12 volts to the fuel pump relay
to energize the electric in-tank fuel pump.
An inoperative fuel pump will cause a “no-start” condition.
A fuel pump which does not provide enough pressure will
result in poor performance.

Fuel Rail

The fuel rail is mounted to the top of the engine and
distributes fuel to the individual injectors.  Fuel is
delivered to the fuel inlet tube of the fuel rail by the fuel
lines.  The fuel goes through the fuel rail to the fuel
pressure regulator.  The fuel pressure regulator maintains

a constant fuel pressure at the injectors.  Remaining fuel
is then returned to the fuel tank.

055RW009

Idle Air Control (IAC) Valve

The purpose of the idle air control (IAC) valve is to control
engine idle speed, while preventing stalls due to changes
in engine load.  The IAC valve, mounted in the throttle
body, controls bypass air around the throttle plate.  By
moving the conical valve (pintle) in (to decrease air flow)
or out  (to increase air flow), a controlled amount of air can
move around the throttle plate.  If the RPM is too low, the
PCM will retract the IAC pintle, resulting in more air
moving past the throttle plate to increase the RPM.  If the
RPM is too high, the PCM will extend the IAC pintle,
allowing less air to move past the throttle plate,
decreasing the RPM.
The IAC pintle valve moves in small steps called counts.
During idle, the proper position of the IAC pintle is
calculated by the PCM based on battery voltage, coolant
temperature, engine load, and engine RPM.  If the RPM
drops below a specified value,  and the throttle plate is
closed, the PCM senses a near-stall condition. The PCM
will then calculate a new IAC pintle valve position to
prevent stalls.
If the IAC valve is disconnected and reconnected with the
engine running, the idle RPM will be wrong.  In this case,
the IAC must be reset.  The IAC resets when the key is
cycled “ON” then “OFF.”  When servicing the IAC, it
should only be disconnected or connected with the
ignition “OFF.”
The position of the IAC pintle valve affects engine start-up
and the idle characteristics of the vehicle.  If the IAC pintle
is fully open, too much air will be allowed into the manifold.
This results in high idle speed, along with possible hard
starting and a lean air/fuel ratio.  DTC P0507 or DTC
P1509 may set.  If the IAC pintle is stuck closed, too little
air will be allowed in the manifold.  This results in a low idle
speed, along with possible hard starting and a rich air/fuel
ratio.  DTC P0506 or DTC P1508 may set.  If the IAC
pintle is stuck part-way open, the idle may be high or low
and will not respond to changes in the engine load.

6E–344

ENGINE DRIVEABILITY AND EMISSIONS

0006

Run Mode

The run mode has the following two conditions:

D

Open loop

D

Closed loop

When the engine is first started the system is in “open
loop” operation.  In “open loop,” the PCM ignores the
signal from the heated oxygen sensor (HO2S).  It
calculates the air/fuel ratio based on inputs from the TP,
ECT, and MAF sensors.
The system remains in “open loop” until the following
conditions are met:

D

The HO2S has a varying voltage output showing that
it is hot enough to operate properly (this depends on
temperature).

D

The ECT has reached a specified temperature.

D

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

D

Engine speed has been greater than a specified RPM
since start-up.

The specific values for the above conditions vary with
different engines and are stored in the programmable
read only memory (PROM).  When these conditions are
met, the system enters “closed loop” operation.  In
“closed loop,” the PCM calculates the air/fuel ratio
(injector on-time) based on the signal from the HO2S.
This allows the air/fuel ratio to stay very close to 14.7:1.

Starting Mode

When the ignition is first turned “ON,” the PCM energizes
the fuel pump relay for two seconds to allow the fuel pump
to build up pressure.  The PCM then checks the engine
coolant temperature (ECT) sensor and the throttle
position (TP) sensor to determine the proper air/fuel ratio
for starting.
The PCM controls the amount of fuel delivered in the
starting mode by adjusting how long the fuel injectors are
energized by pulsing the injectors for very short times.

Throttle Body Unit

The throttle body has a throttle plate to control the amount
of air delivered to the engine.  The TP sensor and IAC
valve are also mounted on the throttle body.  Vacuum
ports located behind the throttle plate provide the vacuum
signals needed by various components.
Engine coolant is directed through a coolant cavity in the
throttle body to warm the throttle valve and to prevent
icing.

0019

General Description (Electronic
Ignition System)

Camshaft Position (CMP) Sensor

As the camshaft sprocket turns, a magnet in the sprocket
activates the Hall-effect switch in the CMP sensor.  When
the Hall-effect switch is activated, it grounds the signal
line to the PCM, pulling the camshaft position sensor
signal circuit’s applied voltage low. This is a CMP signal.
The CMP signals is created as piston #1 is approximately
25

°

 after top dead counter on the power stroke.  If the

correct CMP signal is not received by the PCM, DTC
P0341 will be set.

 

 

 

 

 

 

 

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