Opel Frontera UE. Manual - part 253

 

  Index      Opel     Opel Frontera UE - service repair manual 1999-2001 year

 

Search            

 

 

 

 

 

 

 

 

 

Content   ..  251  252  253  254   ..

 

 

Opel Frontera UE. Manual - part 253

 

 

6E1–310

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

028RX002

GENERAL DESCRIPTION — FUEL
METERING

Acceleration Mode

The ECM 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 ECM will compensate for
the weak spark by increasing the following:

D

The amount of fuel delivered.

D

The idle RPM.

CMP Signal

The ECM uses the camshaft position (CMP) sensor
signal to determine the position of the number 1 piston
during its power stroke, allowing the ECM to calculate
true sequential multiport fuel injection (SFI). Loss of this
signal will set a DTC P0341 or DTC P0342. 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 with the fault is present,
with a 1–in–4 chance of being correct.

Clear Flood Mode

Clear a flooded engine by pushing the accelerator pedal
down all the way. The ECM then de–energizes the fuel
injectors. The ECM 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 ECM again begins to pulse the
injectors ON and OFF, allowing fuel into the cylinders.

Deceleration Fuel Cutoff (DFCO) Mode

The ECM 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 ECM may cut off fuel
completely for short periods.

Engine Speed/Vehicle Speed/ Fuel Disable
Mode

The ECM monitors engine speed. It turns off the fuel
injectors when the engine speed increases above 6000
RPM. The fuel injectors are turned back on when engine
speed decreases below 5750 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
ECM 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 ECM. The
ECM 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 ECM.

D

The crankshaft position (CKP) sensor.

6E1–311

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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 ECM how much oxygen is in the exhaust gas. The
ECM changes the air/fuel ratio to the engine by controlling
the amount of time that the 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
constant measuring and adjusting of the air/fuel ratio, the
fuel injection system is called a ”Closed Loop” system.
The ECM 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 ECM.

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 separately.
If the pressure is too low, poor performance and a DTC
P0171, or DTC P1171 will be the result. If the pressure is
too high, a DTC  P0172  will be the result. For information
on diagnosing fuel pressure conditions, refer to Fuel
System Diagnosis.

014RX038

Fuel Pump Electrical Circuit

When the key is first turned ON, the ECM 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 ECM shuts the fuel pump off and waits until
the engine is cranked. When the engine is cranked and
the 58X crankshaft position signal has been detected by
the ECM, the ECM 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.

014RX036

6E1–312

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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
ECM 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 ECM 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 ECM 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 ECM senses a near–stall condition. The ECM
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  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 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.

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 ECM ignores the
signal from the heated oxygen sensor (HO2S). It
calculates the air/fuel ratio based on inputs from the TP,
ECT, and MAP 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 ECM 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 ECM energizes
the fuel pump relay for two seconds to allow the fuel pump
to build up pressure. The ECM then checks the engine
coolant temperature (ECT) sensor and the throttle
position (TP) sensor to determine the proper air/fuel ratio
for starting.
The ECM 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.

014RX040

6E1–313

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

GENERAL DESCRIPTION —
ELECTRONIC IGNITION SYSTEM

Camshaft Position (CMP)  Sensor

The camshaft position (CMP) sensor sends a  signal to
the ECM. The ECM uses this signal as a ”sync pulse” to
trigger the injectors in the proper sequence. The ECM
uses the CMP signal to indicate the position of the #1
piston during its power stroke. The CMP allows the ECM
to calculate true sequential fuel injection (SFI) mode of
operation. If the ECM detects an incorrect CMP signal
while the engine is running, DTC P0341 will set.
If the CMP signal is lost while the engine is running, the
fuel injection system will shift to a calculated sequential
fuel injection mode based on the last fuel injection pulse,
and the engine will continue to run. It will run in the
calculated sequential mode with a 1–in–4 chance of the
injector being correct.
For additional information, refer to DTC P0342.

014RX007

Crankshaft Position (CKP)  Sensor

The crankshaft position (CKP) sensor provides a signal
used by the engine control module (ECM) to calculate the
ignition sequence. The sensor initiates the 58X reference
pulses which the ECM uses to calculate RPM and
crankshaft position. For additional information, refer to
Electronic Ignition System.

Electronic Ignition

The electronic ignition system controls fuel combustion
by providing a spark to ignite the compressed air/fuel
mixture at the correct time. To provide optimum engine
performance, fuel economy, and control of exhaust
emissions, the ECM controls the spark advance of the
ignition system. Electronic ignition has the following
advantages over a mechanical distributor system:

D

No moving parts.

D

Less maintenance.

D

Remote mounting capability.

D

No mechanical load on the engine.

D

More coil cooldown time between firing events.

D

Elimination of mechanical timing adjustments.

D

Increased available ignition coil saturation time.

0013

Ignition Coils

The 2.2L engine uses 2 ignition coils, 1 per 2 cylinders. A
two–wire connector provides a 12–volt primary supply
through the 15–amp ignition coil fuse, and the ground wire
is connected to a ground–switching ignition module.
Radio frequency interference produced by the coil is
controlled by a condenser which is mounted near the
ignition coil.

014RX044

Ignition Control

The ignition control (IC) spark timing is the ECM’s method
of controlling the spark advance and the ignition dwell.
The IC spark advance and the ignition dwell are
calculated by the ECM using the following inputs:

D

Engine speed.

D

Crankshaft position (58X reference).

D

Camshaft position (CMP) sensor.

 

 

 

 

 

 

 

Content   ..  251  252  253  254   ..