oil type FORD SIERRA 1993 2.G Fuel And Exhaust Systems Fuel Injection Workshop Manual

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

working on the exhaust system, ensure
that the converter is well clear of any
jacks or other lifting gear used to raise the
car and do not drive the car over rough
ground, road humps, etc., in such a way
as to “ground” the exhaust system.
j)In some cases, particularly when the car is
new and/or is used for stop/start driving, a
sulphurous smell (like that of rotten eggs)
may be noticed from the exhaust. This is
common to many catalytic converter-
equipped cars and seems to be due to the
small amount of sulphur found in some
petrols reacting with hydrogen in the
exhaust to produce hydrogen sulphide
(H2S) gas; while this gas is toxic, it is not
produced in sufficient amounts to be a
problem. Once the car has covered a few
thousand miles the problem should
disappear - in the meanwhile a change of
driving style or of the brand of petrol used
may effect a solution.
k)The catalytic converter, used on a well-
maintained and well-driven car, should
last for between 50 000 and 100 000
miles - from this point on, careful checks
should be made at all specified service
intervals of the CO level to ensure that the
converter is still operating efficiently - if
the converter is no longer effective it must
be renewed.
EEC IV module - warning
Following disconnection of the battery, the
information stored in the EEC IV module
memory will be erased. After reconnecting the
battery, the engine should be allowed to idle for
three minutes. Once the engine has reached
normal operating temperature, the idle speed
should be increased to 1200 rpm and
maintained for approximately 2 minutes, which
will allow the module to “re-learn” the optimum
idle values. It may be necessary to drive the
vehicle in order for the module to “re-learn” the
values under load. The module should complete
its learning process after approximately 5 miles
(8 kilometres) of varied driving.
Refer to Chapter 1, Section 38.
2.0 litre SOHC models
1Disconnect the battery negative lead.
2Depress the locking clip on the airflow
meter wiring plug and disconnect the plug.
Pull on the plug, not the wiring.
3Loosen the securing clip and disconnect
the air inlet hose from the airflow meter.
4Release the four securing clips and lift off
the air cleaner lid with the airflow meter.
5Remove the left-hand front wheel arch liner.
6Working under the wheel arch, unscrew the
three air cleaner securing nuts and washers.
7Disconnect the air inlet tube, and withdrawthe air cleaner from the engine compartment.
8Refitting is a reversal of removal.
2.0 litre DOHC models
9Disconnect the battery negative lead.
10Disconnect the wiring plug from the idle
speed control valve at the front of the plenum
chamber.
11Loosen the clamp, and detach the air inlet
hose from the air inlet tubing.
12Unscrew the securing nut, and release the
air inlet tube from the bracket on the engine
compartment front panel.
13Release the air cleaner lid securing clips,
then lift away the air inlet tube, plenum
chamber and air cleaner lid as an assembly,
disconnecting the breather hose from the air
inlet tube.
14Lift out the air cleaner element then wipe
the inside of the air cleaner lid and casing clean.
15Remove the left-hand front wheel arch liner.
16Working under the wheel arch, unscrew the
three air cleaner securing nuts and washers.
17Disconnect the air inlet tube, and
withdraw the air cleaner from the engine
compartment.
18Refitting is a reversal of removal.
1.6 and 1.8 litre (R6A type) CVH
models
1.6 litre
19Remove the screws from the top of the air
cleaner cover.
20Disconnect the cold air inlet hose from the
air cleaner spout or the inlet on the front body
panel. The hose is secured by toggle clips.
21Disconnect the hot air inlet hose from the
air cleaner spout or the hot air shroud on the
exhaust manifold.
22Where applicable, remove the screw
securing the air cleaner body to the camshaft
cover.
23Withdraw the air cleaner and disconnect
the breather hose from the camshaft cover.
24Refitting is a reversal of removal, ensure
the disturbed hoses are securely connected.
1.8 litre
25Undo the two nuts, lift off the air cleaner
cover, and remove the element.26Disconnect the engine breather hose and
the oil separator hose, then undo the three
nuts and lift up the air cleaner casing (see
illustrations).
27Disconnect the yellow striped vacuum
hose from the underside of the casing, detach
the air inlet hose, and remove the air cleaner
assembly.
28Refitting is a reversal of removal, ensuring
all hoses are correctly attached.
1Disconnect the battery negative lead.
2Remove the air cleaner assembly.
3Position a suitable container (or a sufficient
quantity of absorbent cloth) beneath the fuel
inlet connection on the CFI unit.
4Use an open-ended spanner on the flats of
the inlet union screwed into the CFI unit, to
prevent it from turning while the inlet pipe
union is loosened (see illustration). Allow all
pressure/fuel seepage to dissipate before fully
unscrewing the union if it is to be
disconnected, or tightened if another part of
the system is to be worked on.
4Fuel system (1.6 and 1.8 litre
(R6A type) CVH) - depressurisation
3Air cleaner - removal and
refitting
2Air cleaner element - renewal
4B•4Fuel and exhaust systems - fuel injection
3.26b Air cleaner casing attachments - 1.8
litre (R6A) CVH
A Casing retaining nuts (arrowed)
B Vacuum hose (arrowed)
3.26a Air cleaner cover and hose
attachments - 1.8 litre (R6A) CVH
A Cover retaining nuts
B Engine breather hose
C Oil separator hose
Remember to depressurise the
fuel system before loosening any
connections.
Refer to the precautions in
Section 1 before proceeding. The fuel
system will remain pressurised after the
engine is switched off.
4.4 CFI unit fuel inlet union (arrowed)

5The system will remain depressurised until
the fuel pump is primed prior to starting the
engine. Remove the container or cloth, as
applicable, on completion.
Refer to Chapter 1, Section 41.
2.0 litre SOHC models
1Disconnect the battery negative lead.
2Slowly loosen the fuel feed union to relieve
the pressure in the fuel lines.
3Disconnect the fuel feed and return lines.
Be prepared for petrol spillage.
4Disconnect the vacuum pipe from the top
of the pressure regulator.
5Unscrew the securing nut from the base of
the pressure regulator and withdraw the unit
(see illustration).
6Refitting is a reversal of removal, but if the
fuel return line was originally secured with a
crimped type clip, discard this and use a new
worm drive clip.
7On completion check the fuel line
connections for leaks. Pressurise the system by
switching the ignition on and off several times.
2.0 litre DOHC models
Note: A new pressure regulator seal will be
required on refitting.
8Disconnect the battery negative lead.
9Slowly loosen the fuel rail fuel feed union to
relieve the pressure in the system (see
illustration). Be prepared for fuel spillage,
and take adequate fire precautions.
10Disconnect the fuel return hose from the
pressure regulator (see illustration). Again,
be prepared for fuel spillage.
11Disconnect the vacuum pipe from the top
of the pressure regulator.
12Unscrew the two securing bolts, and
withdraw the regulator from the fuel rail.
Recover the seal.13Fit a new seal to the regulator, and
lubricate with clean engine oil.
14Fit both the securing bolts to the
regulator, then position the regulator on the
fuel rail, and tighten the securing bolts.
15Further refitting is a reversal of removal. If
the fuel return line was originally secured with
a crimped-type clip, discard this, and use a
new worm-drive clip.
16On completion, pressurise the system by
switching the ignition on and off several times,
and check the fuel line connections for leaks.
1.6 and 1.8 litre (R6A type) CVH
models
Note:On completion of refitting, the fuel
system pressure should be checked by a Ford
dealer at the earliest opportunity.
1.6 litre
17Remove the CFI unit.
18Remove the four screws securing the
regulator housing to the CFI unit, then
carefully lift off the housing and recover the
ball, cup, large spring, diaphragm, valve, and
small spring, noting the position and
orientation of all components (see
illustration). Do not attempt to prise the plug
from the regulator housing, or adjust the Allen
screw (if no plug is fitted); this will alter the fuel
system pressure.
19Check all components, and renew any
faulty items as necessary.
20Commence reassembly by supporting the
CFI unit on its side, so that the regulator
components can be fitted from above.
6Fuel pressure regulator -
removal and refitting
5Fuel filter - renewal
Fuel and exhaust systems - fuel injection 4B•5
4B
6.9 Fuel rail fuel feed union (arrowed)
6.10 Disconnecting the fuel return hose
(arrowed) from the pressure regulator
6.5 Withdrawing the fuel pressure
regulator
6.18 Exploded view of Central Fuel Injection (CFI) unit
1.6 litre CVH engine application shown - 1.8 litre similar
1 Fuel injector assembly
2 Fuel pressure regulator
components
3 Fuel inlet connector
4 Air charge temperature
(ACT) sensor
5 Throttle valve control
motor
6 Throttle position sensor
7 Fuel injector wiring
Caution: Refer to the
precautions in Section 1 before
proceeding.

Note: A tachometer and an exhaust gas
analyser will be required to check the idle
mixture on completion.
1Disconnect the battery negative lead.
2Depress the locking clip on the airflow
meter wiring plug and disconnect the plug.
Pull on the plug, not the wiring.
3Loosen the securing clip and disconnect
the air inlet hose from the airflow meter.
4Release the four securing clips and lift off
the air cleaner lid with the airflow meter.
5Remove the four securing bolts and
separate the airflow meter from the air cleaner
lid (see illustration). Recover the seal.
6Refitting is a reversal of removal, ensuring
that the seal is correctly located on the air
cleaner lid, and that the air inlet hose clip is
correctly aligned (see illustration).7On completion, check and if necessary
adjust the idle mixture.
1.6 litre
Note: New fuel injector seals must be used on
refitting.
1Disconnect the battery negative lead.
2Remove the air cleaner.
3Depressurise the fuel system.
4Release the securing lugs, and disconnect
the fuel injector wiring plug (see illustration).
5Bend back the injector retaining collar
securing bolt locktabs, then unscrew the
bolts. Remove the injector retaining collar
(see illustrations).
6Withdraw the injector from the CFI unit (see
illustration), noting its orientation, then
withdraw the injector seals.
7Remove the seal from the injector retaining
collar (see illustration).
8Refitting is a reversal of removal, noting the
following points.
9Use new injector seals, and lubricate them
with clean engine oil before fitting.
10Ensure that the locating peg on the
injector is correctly positioned (see
illustration).
1.8 litre
11On these engines, the fuel pressure
regulator and injector are one assembly.
Proceed as described for the fuel pressure
regulator.
1The ballast resistor is located on the right-
hand side of the engine compartment, and is
only fitted to 1.6 litre engines (see
illustration).
2Disconnect the battery negative lead.
3Disconnect the ballast resistor wiring
connector, then remove the securing screw,
and withdraw the ballast resistor from the
body panel.
4Refitting is a reversal of removal.
17Fuel injector ballast resistor
(1.6 litre CVH) - removal and
refitting
16Fuel injector (1.6 and 1.8 litre
(R6A type) CVH) - removal and
refitting
15Airflow meter - removal and
refitting
4B•8Fuel and exhaust systems - fuel injection
15.5 Airflow meter-to-air cleaner lid bolts
(arrowed)
16.4 Disconnecting the fuel injector wiring
plug
16.10 Align locating peg on injector with
slot in CFI unit on refitting - 1.6 litre CVH16.7 Removing the seal from the injector
retaining collar16.6 Withdrawing the fuel injector
16.5b Removing the injector retaining
collar16.5a Removing an injector retaining collar
securing bolt and locktab
15.6 Air intake hose clip correctly aligned
Caution: Refer to the
precautions in Section 1 before
proceeding.