air condition FORD SIERRA 1988 2.G Fuel And Exhaust Systems Fuel Injection Workshop Manual

Torque wrench settingsNmlbf ft
2.0 litre SOHC models
Refer to Chapter 4
, PartA Specifications for items not listed here
Fuel pressure regulator fuel feed union nut . . . . . . . . . . . . . . . . . . . . . .15 to 2011 to 15
Fuel pressure regulator securing nut . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Fuel rail securing bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 106 to 7
Idle speed control valve nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 106 to 7
2.0 litre DOHC models
Inlet manifold nuts and bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2415 to 18
Exhaust manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2515 to 18
Exhaust gas oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 to 7037 to 52
Throttle body bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 to 117 to 8
Fuel rail bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2615 to 19
Idle speed control valve bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 to 117 to 8
Fuel pressure regulator bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 to 127 to 9
Fuel filter unions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 to 2010 to 15
1.6 and 1.8 litre (R6A type) CVH models
Inlet manifold nuts and bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 to 2012 to 15
Exhaust manifold nuts:
1.6 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 to 1710 to 13
1.8 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2715 to 20
Exhaust downpipe-to-manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . .35 to 4026 to 30
CFI unit bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 to 117 to 8
Exhaust gas oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 to 7037 to 52
EGR valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 3015 to 22
Fuel filter unions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 to 2010 to 15
Pulse-air tube unions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 to 3521 to 26
General information
2.0 litre SOHC models
The fuel injection system fitted to these
models is of the Bosch L-Jetronic type. The
system is under the overall control of an EEC
IV engine management system which also
controls the ignition timing.
Fuel is supplied from the rear-mounted fuel
tank by an electric fuel pump mounted next to
the tank, via a pressure regulator, to the fuel
rail. The fuel rail acts as a reservoir for the four
fuel injectors, which inject fuel into the cylinder
inlet tracts, upstream of the inlet valves. The
fuel injectors receive an electrical pulse once
per crankshaft revolution, which operates all
four injectors simultaneously. The duration of
the electrical pulse determines the quantity of
fuel injected, and pulse duration is computed
by the EEC IV module on the basis of
information received from the various sensors.
Inducted air passes from the air cleaner
through a vane type airflow meter before
passing to the cylinder inlet tracts via the
throttle valve. A flap in the vane airflow meter
is deflected in proportion to the airflow; this
deflection is converted into an electrical signal
and passed to the EEC IV module. An
adjustable air bypass channel provides the
means of idle mixture adjustment.
A throttle position sensor enables the EEC IV
module to compute not only throttle position,
but also its rate of change. Extra fuel can thus
be provided for acceleration when the throttle
is opened suddenly. Information from the
throttle position sensor is also used to cut off
fuel on the overrun, thus improving fueleconomy and reducing exhaust gas emissions.
Idle speed is controlled by a variable orifice
solenoid valve which regulates the amount of
air bypassing the throttle valve. The valve is
controlled by the EEC IV module; there is no
provision for adjustment of the idle speed.
Additional sensors inform the EEC IV
module of engine coolant and air temperature.
On models fitted with automatic transmission,
a sensor registers the change from “P” or “N”
to a drive position, and causes the idle speed
to be adjusted accordingly to compensate for
the additional load. Similarly on models fitted
with air conditioning, a sensor registers when
the compressor clutch is in operation.
A “limited operation strategy” (LOS) means
that the vehicle is still driveable, albeit at
reduced power and efficiency, in the event of
a failure in the EEC IV module or its sensors.
A fuel filter is incorporated in the fuel supply
line to ensure that the fuel supplied to the
injectors is clean.
On models produced from mid-1986
onwards, a fuel pump inertia cut-off switch is
fitted. This switch breaks the electrical circuit
to the fuel pump in the event of an accident or
similar impact, cutting off the fuel supply to
the engine.
2.0 litre DOHC models
The fuel injection system fitted to these
models is under the overall control of an EEC
IV engine management system which also
controls the ignition timing.
Fuel is supplied from the rear-mounted fuel
tank by an electric fuel pump, which is integral
with the fuel level sender unit mounted inside
the fuel tank. Fuel passes via a fuel filter and a
pressure regulator to the fuel rail. The fuel rail
acts as a reservoir for the four fuel injectors,
which inject fuel into the cylinder inlet tracts,
upstream of the inlet valves. The fuel injectorsare operated in pairs by electrical pulses
supplied by the EEC IV module, and fuel is
injected by one pair of injectors every half-
revolution of the crankshaft. The duration of
each electrical pulse determines the quantity of
fuel injected, and pulse duration is computed
by the EEC IV module on the basis of
information received from the various sensors.
Inducted air passes through the air cleaner,
and through a plenum chamber, before
passing on to the cylinder inlet tracts via the
throttle valve and inlet manifold. The volume
of air entering the engine is calculated by the
EEC IV module from information supplied by
various sensors. These sensors include an air
charge temperature sensor mounted in the
inlet manifold, which measures the
temperature of the air entering the engine; a
manifold absolute pressure (MAP) sensor,
which measures the pressure of the air
entering the engine; a throttle position sensor;
and a crankshaft speed/position sensor,
which supplies information on engine speed
and provides a timing reference.
Additional sensors inform the EEC IV
module of fuel temperature, engine coolant
temperature, and vehicle speed (from a
gearbox-mounted sensor).
Idle speed is controlled by a variable-orifice
solenoid valve, which regulates the amount of
air bypassing the throttle valve. The valve is
controlled by the EEC IV module; there is no
provision for direct adjustment of the idle
speed.
On models without a catalytic converter,
idle mixture adjustment is by means of a
potentiometer connected directly to the EEC
IV module. On models with a catalytic
converter, an exhaust gas oxygen (HEGO)
sensor enables the EEC IV module to control
the fuel/air mixture to suit the operating
parameters of the catalytic converter; no
1General information and
precautions
4B•2Fuel and exhaust systems - fuel injection

manual mixture adjustment is possible.
On models with a catalytic converter, an
evaporative emission control (EVAP) system is
fitted. This prevents the release of fuel vapour
into the atmosphere. With the ignition
switched off, vapours from the fuel tank are
fed to a carbon canister, where they are
absorbed. When the engine is started, the
EEC IV module opens a purge solenoid valve,
and the fuel vapours are fed into the inlet
manifold and mixed with fresh air. This cleans
the carbon filter. A blow-back valve prevents
inlet air being forced back into the fuel tank.
A fuel pump inertia switch is fitted. This
switch breaks the electrical circuit to the fuel
pump in the event of an accident or similar
impact, cutting off the fuel supply to the engine.
A “limited operation strategy” (LOS) means
that the vehicle will still be driveable, albeit at
reduced power and efficiency, in the event of
a failure in the EEC IV module or its sensors.
1.6 and 1.8 litre (R6A type) CVH models
The fuel injection system fitted to these
models is under the overall control of an EEC
IV engine management system which also
controls the ignition timing.
Fuel is supplied from the rear-mounted fuel
tank by an electric fuel pump which is integral
with the fuel level sender unit mounted inside
the fuel tank. Fuel passes via a fuel filter to the
Central Fuel Injection (CFI) unit. A fuel
pressure regulator, mounted on the CFI unit,
maintains a constant fuel pressure to the fuel
injector. Excess fuel is returned from the
regulator to the tank.
The CFI unit, resembling a carburettor,
houses the throttle valve, throttle valve control
motor, throttle position sensor, air charge
temperature sensor, fuel injector, and
pressure regulator.
The duration of the electrical pulse supplied
to the fuel injector determines the quantity of
fuel injected, and pulse duration is computed
by the EEC IV module on the basis of
information received from the various sensors.
The fuel injector receives a pulse twice per
crankshaft revolution under normal operating
conditions, and once per crankshaft
revolution under engine idle conditions. A
ballast resistor is used in the fuel injector
control circuit on 1.6 litre engines.
Inlet air passes through the air cleaner into
the CFI unit. The volume of air entering the
engine is calculated by the EEC IV module from
information supplied by various sensors. These
sensors include the air charge temperature
sensor and throttle position sensor, mounted in
the CFI unit; a crankshaft speed/position
sensor which supplies information on engine
speed; and a manifold absolute pressure (MAP)
sensor which measures the pressure of the air
entering the engine.
Additional sensors inform the EEC IV module
of engine coolant temperature, and vehicle
speed (from a gearbox-mounted sensor).
An exhaust gas oxygen (HEGO) sensor
enables the EEC IV module to control the
fuel/air mixture to suit the operating
parameters of the catalytic converter. No
manual mixture adjustment is possible.
Idle speed is controlled by a throttle valvecontrol motor, which controls the position of
the throttle valve under conditions of idling,
deceleration/part-throttle, and engine start-up
and shut-down.
On 1.6 litre engines, a pulse-air system is
fitted to reduce the exhaust gas emissions
during engine warm-up. The system is con-
trolled by a vacuum-operated valve, which is
operated by the EEC IV module via a solenoid.
The system introduces air into the exhaust
manifold to increase the exhaust gas
temperature, which oxidises more of the
pollutants, and brings the catalyst up to
working temperature more quickly. The
system operates until the catalyst reaches
operating temperature, when the control
solenoid shuts off the system.
On 1.8 litre engines, an exhaust gas
recirculation (EGR) system is used to
recirculate a small amount of exhaust gas into
the inlet manifold. This process lowers the
combustion temperature, resulting in a
reduction of NOx (oxides of nitrogen)
emissions. The EGR system is controlled by
the EEC IV module in conjunction with an
Electronic Pressure Transducer (EPT) and an
Electronic Vacuum Regulator (EVR).
On certain models, an evaporative emission
control system may be fitted. This prevents
the release of fuel vapour into the
atmosphere. With the ignition switched off,
vapours from the fuel tank are fed to a carbon
canister, where they are absorbed. When the
engine is started the EEC IV module opens a
purge solenoid valve, and the fuel vapours are
fed into the inlet manifold and mixed with
fresh air. This cleans the carbon filter. A blow-
back valve prevents inlet air being forced
back into the fuel tank.
A fuel pump inertia switch is fitted. This
switch breaks the electrical circuit to the fuel
pump in the event of an accident or similar
impact cutting off the fuel supply to the engine.
A “limited operation strategy” (LOS) means
that the vehicle will still be driveable, albeit at
reduced power and efficiency, in the event of
a failure in the EEC IV module or its sensors.
Precautions
Many of the procedures in this Chapter
require the removal of fuel lines and
connections which may result in some fuel
spillage. Before carrying out any operation on
the fuel system refer to the precautions given
in “Safety first!” at the beginning of this
Manual and follow them implicitly. Petrol is a
highly dangerous and volatile liquid and the
precautions necessary when handling it
cannot be overstressed.
Residual pressure will remain in the fuel
lines long after the vehicle was last used,
therefore extra care must be taken when
disconnecting a fuel line hose. Loosen any
fuel hose slowly to avoid a sudden release of
pressure which may cause fuel spray. As an
added precaution place a rag over each union
as it is disconnected to catch any fuel which is
forcibly expelled.
Certain adjustment points in the fuel system
(and elsewhere) are protected by
“tamperproof” caps, plugs or seals. The
purpose of such tamperproofing is todiscourage, and to detent, adjustment by
unqualified operators.
In some EEC countries (though not yet in
the UK) it is an offence to drive a vehicle with
missing or broken tamperproof seals. Before
disturbing a tamperproof seal, satisfy yourself
that you will not be breaking local or national
anti-pollution regulations by doing so. Fit a
new seal when adjustment is complete when
this is required by law.
Do not break tamperproof seals on a
vehicle which is still under warranty.
Catalytic converter - precautions
The catalytic converter is a reliable and simple
device which needs no maintenance in itself,
but there are some facts of which an owner
should be aware if the converter is to function
properly for the full service life.
a)DO NOT use leaded petrol in a car
equipped with a catalytic converter the
lead will coat the precious metals,
reducing their converting efficiency and
will eventually destroy the converter.
b)Always keep the ignition and fuel systems
well-maintained in accordance with the
manufacturers schedule, ensure that the
air cleaner filter element, the fuel filter
(where fitted) and the spark plugs are
renewed at the correct interval if the inlet
air/fuel mixture is allowed to become too
rich due to neglect, the unburned surplus
will enter and burn in thecatalytic
converter, overheating the element and
eventually destroying the converter.
c)If the engine develops a misfire, do not
drive the car at all (or at least as little as
possible) until the fault is cured - the
misfire will allow unburned fuel to enter
the converter, which will result in
overheating, as noted above.
d)DO NOT push- or tow-start the car - this
will soak the catalytic converter in
unburned fuel, causing it to overheat when
the engine does start - see b) above.
e)DO NOT switch off the ignition at high
engine speeds - if the ignition is switched
off at anything above idle speed,
unburned fuel will enter the (very hot)
catalytic converter, with the possible risk
of igniting on the element and damaging
the converter.
f)DO NOT use fuel or engine oil additives -
these may contain substances harmful to
the catalytic converter.
g)DO NOT continue to use the car if the
engine burns oil to the extent of leaving a
visible trail of blue smoke - the unburned
carbon deposits will clog the converter
passages and reduce the efficiency; in
severe cases the element will overheat.
h)Remember that the catalytic converter
operates at very high temperatures - hence
the heat shields on the car’s underbody
and the casing will become hot enough to
ignite combustible materials which brush
against it - DO NOT, therefore, park the car
in dry undergrowth, over long grass or
piles of dead leaves.
i)Remember that the catalytic converter is
FRAGILE, do not strike it with tools during
servicing work, take great care when
Fuel and exhaust systems - fuel injection 4B•3
4B