1989 FORD FIESTA fuel pressure

14Prise free and remove the tamperproof
seal, then unscrew and remove the idle
mixture adjustment screw.
15 Undo the retaining screws, and remove
the throttle housing from the carburettor main
body.
Cleaning and inspection
16 Wash the carburettor components,
drillings and passages with clean petrol, then
blow them dry using a low-pressure air line. A
high-pressure air line must not be applied to
the accelerator pump discharge assembly or
the pump supply valve, as they each contain a
rubber Vernay valve, and these can easily be
damaged under high pressure. Never use a
piece of wire for cleaning purposes.
17 Examine all of the carburettor
components for signs of damage or wear,
paying particular attention to the diaphragms,
throttle spindle and plates, needle valve and
mixture screw; the power valve jet is adjacent
to the primary main jet. Renew all
diaphragms, sealing washers and gaskets as
a matter of course.
Reassembly
18 Refit the throttle housing to the
carburettor main body (fitting a new gasket),
and secure with its retaining screws.
19 Refit the idle mixture adjustment screw.
Make an initial adjustment by screwing it fully
in (but do not overtighten or screw it onto its
seat), then unscrew it two full turns.
20 Where fitted, reassemble the throttle
kicker, ensuring that its diaphragm lies flat,
and that the relative position of the operating
link to the kicker cover is correct.
21 Fit the power valve, ensuring that its
diaphragm lies flat and the vacuum
gallery aligns with the diaphragm and
housing.
22 Refit the accelerator pump. Take care not
damage the valve as it is inserted, and check
that the O-ring seal is correctly located on the
end of the valve. Check that the valve is not
trapped by the spring.
23 Refit the accelerator pump discharge jet.
Take care not to damage the valve and/or the
O-ring seal, and ensure that they are correctly
located.
24 Commence reassembly of the upper body
by inserting the emulsion tubes and the air
correction jets into their respective ports (as
noted during removal).
25 Screw the anti-dieseling solenoid into
position. Ensure that the aluminium washer is
fitted, and take care not to overtighten the
valve.
26 Refit the needle valve and the float, and
adjust the float setting as described in Sec-
tion 20.
27 Refit the choke control mechanism, and
secure with its three retaining screws.
28 Locate a new gasket onto the mating
face, then refit the carburettor upper body to
the main body. As they are reassembled, take
care not to snag the float on the carburettor main body. Fit and tighten the retaining
screws to secure.
29
On completion, refit the carburettor as
described in Section 23. Where applicable,
check and adjust the throttle kicker setting
(Section 21) after adjusting the idle speed and
mixture settings.
25 Carburettor (Weber DFTM) -
description
The carburettor operates in essentially the
same manner as TLDM instrument described
in Section 18, but the following features
should be noted. A throttle kicker is fitted to both manual
transmission, and CTX automatic trans-
mission models, the operation of the unit is
described in Section 18. The secondary venturi (barrel) is vacuum-
operated on manual transmission models. On
CTX automatic transmission equipped models
it is operated sequentially. A bleed back solenoid (if fitted) is used to
control the amount of fuel being delivered to
the venturi by the action of the accelerator
pump. Idle speed and mixture adjustment
procedures are described in Chapter 1, but it
is important to note that accurate adjustments
can only be made using the necessary
equipment.
26 Carburettor (Weber DFTM) -
fast-idle speed adjustment
4
Refer to the procedure contained in Sec-
tion 19, but note the following points:
a) When removing the air cleaner, do not disconnect the vacuum supply or
crankcase ventilation hoses; the air
cleaner should be positioned clear of the
carburettor assembly.
b) The fast-idle adjusting screw is located
on the side of the linkage (see
illustration) .
27 Throttle kicker unit (Weber
DFTM carburettor) - removal,
refitting and adjustment
4
Refer to the procedure contained in Sec-
tion 21.
28 Carburettor (Weber DFTM) -
removal and refitting
4
Note: Refer to the warning note in Section 1
before proceeding. New gaskets will be
required on refitting, and a tachometer and an
exhaust gas analyser will be required on
completion.
Removal
1 Disconnect the battery negative (earth) lead
(refer to Chapter 5A, Section 1).
2 Remove the air cleaner as described in
Section 2.
3 Disconnect the choke cable from the
carburettor (Section 6).
4 Carefully prise out the accelerator link
retaining clip, remove both securing bolts,
then detach the cable and bracket assembly.
Position the cable and bracket assembly clear
of the carburettor.
5 Disconnect the fuel feed hose at the
carburettor, and plug its end to avoid spillage
and prevent dirt ingress. If a crimped type
hose clip is fitted, cut this free taking care not
to damage the hose.
6 Disconnect all relevant vacuum pipes from
the carburettor, having labelled them for
subsequent refitting.
7 Disconnect the electrical lead from the anti-
dieseling (fuel cut-off) solenoid, and the bleed
back solenoid (if fitted).
8 Remove the four nuts securing the
carburettor to the inlet manifold, then
withdraw it from the vehicle.
Refitting
9 Clean the carburettor and manifold gasket
mating faces.
10 Refit in the reverse order of removal. Fit a
new gasket, and tighten the retaining screws
securely. Ensure that the fuel supply
hose connection to the carburettor is
securely fitted, using a new screw type
retaining clip.
11 Reconnect the choke cable, and adjust it
as described in Section 6.
12 Refer to Section 2 and refit the air
cleaner.
13 When the battery is reconnected, start
and warm up the engine then check the idle
speed and mixture settings as described in
Chapter 1.
Fuel system – carburettor engines 4A•13
26.1 Manual choke fast-idle adjustment. Inset shows fast-idle adjusting screw (Weber DFTM carburettor)
4A
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16Prise out the tamperproof seal covering
the fuel mixture screw, then undo and remove
the mixture screw.
Cleaning and inspection
17 Wash the carburettor components,
drillings and passages with clean petrol, then
blow them dry using a low-pressure air line. A
high-pressure air line must not be applied to
the accelerator pump discharge assembly or
the pump supply valve, as they each contain a
rubber Vernay valve, and these can easily be
damaged under high pressure. Never use a
piece of wire for cleaning purposes.
18 Examine all of the carburettor
components for signs of damage or wear,
paying particular attention to the diaphragms,
throttle spindle and plates, needle valve and
mixture screw; the power valve jet is adjacent
to the primary main jet. Renew all
diaphragms, sealing washers and gaskets as
a matter of course.
Reassembly
19 Refit the fuel mixture screw by fully
winding the screw in, then unwinding three
turns to give an approximate setting.
20 Refit the power valve assembly ensuring
that the diaphragm lies flat, and that the
vacuum gallery lines up correctly with the
diaphragm and housing.
21 Reassemble the secondary barrel
diaphragm into its housing, ensuring that
the diaphragm lies flat and that the vacuum
gallery lines up with the diaphragm and
housing. Also, to assist with installation, do
not reconnect its operating rod until the cover
has been secured.
22 Refit the throttle kicker mounting bracket.
23 Refit the anti-dieseling (fuel cut-off)
solenoid, using a new sealing washer.
24 Refit the accelerator pump assembly,
ensuring that the diaphragm lies flat and is not
kinked.
25 Reassemble the throttle kicker, ensuring
that the diaphragm lies flat and that the relative position of the diaphragm operating
link to the throttle kicker cover is correct. Fully
attach the throttle kicker assembly.
26
Refit the main and idle jets, making
reference to the notes taken during
dismantling to ensure correct fitted locations.
27 Reassemble the carburettor upper body
as described in the following paragraphs.
28 Refit the needle valve housing (using a
new washer if applicable).
29 Refit the needle valve and float assembly,
having ensured that the float tag locates
below the spring clip on the needle valve.
Insert the float retaining pin to secure.
30 Adjust the float level as follows. Ensuring
that a new gasket is fitted to the carburettor
upper body, hold the upper body in the
vertical position; the needle valve must be
shut off. Measure the distance shown (see
illustration) , and adjust by bending the float
tag if the measurement is outside the
specification. Recheck the float level
adjustment after bending the float tag, as
necessary.
31 Refit the choke pull-down diaphragm,
ensuring that the diaphragm lies flat and that
the vacuum gallery lines up correctly with the
diaphragm and housing (see illustration).
32 Adjust the choke pull-down as follows.
Fully close the choke, then manually push the
diaphragm operating rod up to its stop;
measure the distance between the
downdraught side of the choke plate and the
venturi, using a gauge rod or the shank of a
twist drill bit (of known size). If the
measurement is outside specification, remove
the tamperproof seal from the housing, and
adjust the now revealed adjustment screw
accordingly. Fit a new tamperproof seal after
successful adjustment.
33 Refit the fuel feed filter, and secure with
its brass nut and sealing washer.
34 Refit the carburettor upper body to the
carburettor main body, ensuring that its new
gasket seats correctly and that the float does
not foul during assembly. Insert and tighten
the securing screws. 35
Reconnect any vacuum pipes removed
during dismantling (where applicable).
36 On completion, refit the carburettor as
described in Section 28. Where applicable,
check and adjust the throttle kicker setting
(Section 27) after adjusting the idle speed and
mixture settings.
30 Carburettor (Weber TLD) -
description
This carburettor incorporates many of the
features of the TLDM type described in
Section 18. The main differences are that a
throttle kicker is not used, the secondary
venturi (barrel) is vacuum-operated, and that a
coolant-heated automatic choke control
system is fitted. The choke system is fully automatic. When
the engine is cold, the bi-metal spring which
controls the position of the choke plate is fully
wound up, and holds the plate closed. As the
engine warms up, the bi-metal spring is
heated by the coolant and begins to unwind,
thereby progressively opening the choke
plate. A vacuum-operated pull-down
mechanism controls the choke plate under
certain operating conditions, and an internal
fast-idle system is incorporated. Idle speed and mixture adjustment
procedures are described in Chapter 1, but it
is important to note that accurate adjustments
can only be made using the necessary
equipment.
31 Carburettor (Weber TLD) -
fast-idle speed adjustment
4
Note: Before carrying out any carburettor
adjustments, ensure that the spark plug gaps
are set as specified, and that all electrical and
vacuum connections are secure. To carry out
checks and adjustments, an accurate
Fuel system – carburettor engines 4A•15
29.31 Exploded view of the choke pull-down assembly (Weber DFTM carbur\
ettor)
A Housing B Diaphragm
29.30 Float level adjustment (Weber DFTMcarburettor)
A Float level setting dimension
B Adjusting tag
4A
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tachometer and an exhaust gas analyser (CO
meter) will be required.
1Check that the idle speed and mixture
settings are as specified (as described in
Chapter 1). These must be correct before
checking/adjusting the fast-idle speed.
2 Switch the engine off, then remove the air
cleaner as described in Section 2.
3 With the engine at its normal operating
temperature and a tachometer connected in
accordance with its manufacturer’s
instructions, hold the throttle linkage partly
open, then close the choke plate until the fast-
idle adjusting screw aligns with the third
(middle) step on the fast-idle cam (see
illustration) . Release the throttle linkage so
that the fast-idle speed adjusting screw rests
on the cam. Release the choke plate. The
linkage will hold it in the fast-idle speed
setting position, as long as the accelerator
pedal is not depressed.
4 Without touching the accelerator pedal,
start the engine and record the fast-idle speed
achieved. If adjustment is required, turn the
fast-idle speed adjusting screw until the
specified fast-idle speed is obtained.
5 When the throttle linkage is opened, the
choke plate should return to its fully-open
position. If this does not happen, either the engine is not at its normal operating
temperature, or the automatic choke
mechanism is faulty.
6
Switch off the engine and disconnect the
tachometer. Refit the air cleaner.
32 Needle valve and float (Weber
TLD carburettor) - removal,
refitting and adjustment
4
1 Refer to Section 20 and proceed as
described, noting the following difference.
2 In paragraph 4, ignore the instruction to
detach the choke cable (an automatic choke
is fitted to the TLD type carburettor). Instead,
clamp the coolant supply and return hoses
which lead to the automatic choke unit to
minimise coolant loss, then ensure that the
cooling system is not pressurised (see
Chapter 1). Identify then detach both of the
coolant hoses at the automatic choke
housing. Catch any coolant spillage in a
suitable container .
Warning: DO NOT attempt to
remove the expansion tank filler
cap, or to disturb any part of the
cooling system, while it or the
engine is hot, as there is a very great risk
of scalding. If the expansion tank filler cap
must be removed before the engine and
radiator have fully cooled down (even
though this is not recommended) the
pressure in the cooling system must first
be released. Cover the cap with a thick
layer of cloth, to avoid scalding, and slowly
unscrew the filler cap until a hissing sound
can be heard. When the hissing has
stopped, showing that pressure is
released, slowly unscrew the filler cap
further until it can be removed; if more
hissing sounds are heard, wait until they
have stopped before unscrewing the cap
completely. At all times, keep well away
from the filler opening.
3 On completion, reconnect the hoses to the
automatic choke unit, and remove the clamps
from the hoses. Check and top-up the coolant
level on completion (see “Weekly Checks”and
Chapter 1).
33 Automatic choke (Weber TLD carburettor) - adjustment
3
1Disconnect the battery negative (earth) lead
(refer to Chapter 5A, Section 1).
2 Remove the air cleaner as described in
Section 2.
3 Disconnect the coolant hoses to the choke
unit as described in paragraph 2 of the
previous Section.
4 Note the position of the choke coil housing
alignment marks, then undo the three
retaining screws and withdraw the automatic
choke bi-metal coil housing (see illustration).
5 Remove the inner heat shield (see
illustration) . To check and adjust the choke
vacuum pull-down, secure the choke plate
lever in the closed position by fitting a rubber
band, open the throttle to allow the choke
plate to fully close, then release the throttle.
6 Using a screwdriver, push the operating
arm to the right against its spring, and
measure the clearance between the lower
edge of the choke plate and the venturi using
a twist drill or other suitable gauge rod (see
illustration) . Where the clearance is outside
that specified, remove the plug from the
diaphragm housing, and turn the adjusting
screw (now exposed) in the required direction.
7 Fit a new diaphragm housing plug and
remove the rubber band.
8 Refit the heat shield so that its slotted hole
engages over the choke housing peg.
9 Refit the bi-metal coil housing by first
connecting the bi-metal spring to the choke
lever (ensuring correct engagement), locate
the housing and hand-tighten the three
retaining screws. Rotate the housing to align
the index line on the housing with the dot
mark on the choke main body, then retighten
the retaining screws.
10 Reconnect the coolant hoses with
reference to paragraph 3 in the previous
Section.
11 Refit the air cleaner as described in
Section 2.
4A•16 Fuel system – carburettor engines
33.6 Choke plate pull-down adjustment (Weber TLD carburettor)
A Twist drill C Adjusting screw
B Diaphragm held fully open33.5 Automatic choke internal heatshield (Weber TLD carburettor)33.4 Automatic choke housing alignment(Weber TLD carburettor)
A Dot punch mark
B Choke housing alignment mark
1595Ford Fiesta Remake
31.3 Fast-idle speed adjustment
(Weber TLD carburettor) (Housing cut away for illustration clarity)
A Fast-idle cam
B Fast-idle speed adjusting screw on third step of cam
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34 Automatic choke (WeberTLD carburettor) - removal,
inspection and refitting
4
Note: Refer to the warning note in Section 1
before proceeding. A new carburettor upper
body gasket will be required when
reassembling. On completion, a tachometer
will be required to check the fast-idle speed
adjustment.
Removal
1 Disconnect the battery negative (earth) lead
(refer to Chapter 5A, Section 1).
2 Remove the air cleaner as described in
Section 2.
3 To prevent excess coolant loss, clamp the
coolant supply and return hoses to the
automatic choke unit, and ensure that the
cooling system is not pressurised (see
Chapter 1). Identify then detach both of the
coolant hoses at the automatic choke
housing. Catch any coolant spillage in a
suitable container.
Warning: DO NOT attempt to
remove the expansion tank filler
cap, or to disturb any part of the
cooling system, while it or the
engine is hot, as there is a very great risk
of scalding. If the expansion tank filler cap
must be removed before the engine and
radiator have fully cooled down (even
though this is not recommended) the
pressure in the cooling system must first
be released. Cover the cap with a thick
layer of cloth, to avoid scalding, and slowly
unscrew the filler cap until a hissing sound
can be heard. When the hissing has
stopped, showing that pressure is
released, slowly unscrew the filler cap
further until it can be removed; if more
hissing sounds are heard, wait until they
have stopped before unscrewing the cap
completely. At all times, keep well away
from the filler opening.
4 Detach the fuel pipe and the anti-dieseling
solenoid wiring connector. Any crimped type
hose clips must be replaced with a screw
clamp type clips during reassembly.
5 Unscrew and remove the retaining screws (two conventional, and four Torx type), then lift
the carburettor upper body clear and remove it.
6
Note the position of the choke housing
alignment marks, then undo the three retaining
screws and remove the choke bi-metal coil
unit. Remove the internal heat shield.
7 To remove the automatic choke unit, undo
the three retaining screws and detach the
choke link from the operating lever (see
illustration) .
8 Undo the three retaining screws to remove
the vacuum diaphragm unit.
9 If dismantling the choke mechanism any
further, note the component fitment as an aid
to reassembly, but do not detach the choke
spindle.
Inspection
10 Clean and inspect all components for
wear, damage and/or distortion. Pay
particular attention to the condition of the
vacuum (pull-down) diaphragm and the choke
housing O-ring. Renew any items that are
defective (or suspect).
Refitting
11 Reassemble the automatic choke
mechanism, making references to the notes
taken during dismantling. Note that no
lubricants must be used (see illustration).
12 Refit the vacuum unit, making reference to
the notes taken during dismantling. Ensure
that the diaphragm is lying flat before
tightening the housing retaining screws.
13 Locate the O-ring (ensuring that it is
correctly seated), then reconnect the choke
link. Refit the automatic choke unit, and secure
with the retaining screws. Check and adjust
the choke vacuum pull-down as described
in the previous Section (paragraphs 5 and 6).
14 Refit the inner heat shield, ensuring that
the location peg is securely engaged in its
notch.
15 Refit the automatic choke housing and the
bi-metal spring unit as described in the
previous Section (paragraph 9).
16 Refit the carburettor upper body, ensuring
that a new gasket is used and that the mating
surfaces are clean. Fit the retaining screws to
secure.
17 Reconnect the fuel hose to the carburettor,
using new screw type hose clips to secure it.
18 Reconnect the anti-dieseling solenoid
wiring connector.
19 Reconnect the coolant hoses to the
automatic choke unit, then check and if necessary top-up the cooling system as
described in “
Weekly Checks ” and Chapter 1.
20 Reconnect the battery negative lead, then
check and adjust the fast-idle speed as
described in Section 31.
21 Refit the air cleaner (Section 2).
35 Carburettor (Weber TLD) -
removal and refitting
4
Note: Refer to the warning note in Section 1
before proceeding. New gaskets will be required
on refitting and a tachometer and an exhaust gas
analyser will be required on completion.
Removal
1 Disconnect the battery negative (earth) lead
(refer to Chapter 5A, Section 1).
2 Remove the air cleaner as described in
Section 2.
3 Release any pressure remaining in the
cooling system (see Chapter 1), and then
detach the two coolant hoses from the
automatic choke unit. Catch any coolant
spillage in a suitable container. Identify each
hose for subsequent refitting, then plug their
ends or position them as high as possible to
prevent coolant leakage. Warning: DO NOT attempt to
remove the expansion tank filler
cap, or to disturb any part of the
cooling system, while it or the
engine is hot, as there is a very great risk of
scalding. If the expansion tank filler cap
must be removed before the engine and
radiator have fully cooled down (even
though this is not recommended) the
pressure in the cooling system must first be
released. Cover the cap with a thick layer of
cloth, to avoid scalding, and slowly unscrew
the filler cap until a hissing sound can be
heard. When the hissing has stopped,
showing that pressure is released, slowly
unscrew the filler cap further until it can be
removed; if more hissing sounds are heard,
wait until they have stopped before
unscrewing the cap completely. At all times,
keep well away from the filler opening.
4 Disconnect the accelerator cable from the
linkage at the carburettor, as described in
Section 3.
5 Detach the anti-dieseling solenoid wiring
connector.
6 Detach the fuel feed hose at the carburettor.
Fuel system – carburettor engines 4A•17
34.11 Exploded view of the automatic choke linkage (Weber TLD carburet\
tor)
34.7 Automatic choke assembly
(Weber TLD carburettor)
A Pull-down diaphragm housing
B Securing screws
4A
1595Ford Fiesta Remake
A Operating link/fast-idle cam
B Fast-idle cam return spring
C Spindle sleeve
D Connecting rod and lever assembly
E Pull-down kink
F Actuating lever
G Automatic choke housing
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4B
1595Ford Fiesta Remake
General
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . . . . . Central Fuel injection (CFi)
Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . . . . . . 1.1 and 1.3 litre HCS engines and 1.4 litre CVH engines
Fuel grade
Fuel octane requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. 95 RON unleaded
Fuel system data
Regulated fuel pressure - engine running at idle speed . . . . . . . . . . . . . 1.0 ± 0.1 bars
Hold pressure - engine stopped after 1 minute . . . . . . . . . . . . . . . . . . . 0.5 bars minimum
Torque wrench settingsNmlbf ft
CFi unit-to-inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
12 to 15 9 to 11
Inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . . . . 16 to 20 12 to 15
Inlet air temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 to 25 15 to 18
Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . . . 50 to 70 37 to 52
Chapter 4 Part B:
Fuel system - central fuel injection engines
Accelerator cable - removal, refitting and adjustment . . . . . . . . . . . 5
Accelerator pedal - removal and refitting . . . . . . . . . . . . . . . . . . . . . 6
Air cleaner assembly and air inlet components - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .\
. . . . . . . . . . 4
Air cleaner element renewal . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Fuel cut-off switch - removal and refitting . . . . . . . . . . . . . . . . . . . . 12
Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . \
. . . . .See Chapter 1
Fuel injection system - checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Fuel injection system components - removal and refitting . . . . . . . . 14
Fuel lines and fittings - general information . . . . . . . . . . . . . . . . . . . 3
Fuel pump/fuel gauge sender unit - removal and refitting . . . . . . . . 9 Fuel pump/fuel pressure - checking . . . . . . . . . . . . . . . . . . . . . . . . . 7
Fuel system - depressurisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fuel tank - removal, inspection and refitting . . . . . . . . . . . . . . . . . . . 8
Fuel tank filler pipe - removal and refitting . . . . . . . . . . . . . . . . . . . . 11
Fuel tank ventilation tube - removal and refitting . . . . . . . . . . . . . . . 10
General fuel system checks . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
General information and precautions . . . . . . . . . . . . . . . . . . . . . . . . 1
Inlet manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 15
Underbody fuel/brake line check . . . . . . . . . . . . . . . . . . .See\
Chapter 1
Underbonnet check for fluid leaks and hose condition . .See Chapter 1
4B•1
Specifications Contents
Easy,
suitable for
novice with little
experience Fairly easy,
suitable
for beginner with
some experience Fairly difficult,
suitable for competent
DIY mechanic
Difficult,
suitable for
experienced DIY
mechanic Very difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
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1 General information andprecautions
General information
The fuel system consists of a fuel tank
(mounted under the body, beneath the rear
seats), fuel hoses, an electric fuel pump
mounted in the fuel tank, and a central fuel
injection (CFi) system. Fuel is supplied from the tank by an integral
electric fuel pump (and combined fuel gauge
sender unit). The fuel is passed through an in-
line filter within the engine compartment, then
to the fuel injection unit. The fuel is maintained
at the required operating pressure by a
pressure regulator unit. The CFi unit itself is a relatively simple
device when compared with a conventional
carburettor. Fuel is injected by a single
solenoid valve (fuel injector) which is mounted
centrally on top of the unit. It is this feature
which gives the system CFi (or Central Fuel
injection) its name (see illustration).The injector is energised by an electrical
signal sent from the EEC IV engine
management module. When energised, the
injector pintle is lifted from its seat, and
atomised fuel is delivered into the inlet
manifold under pressure. The electrical
signals take two forms of current - a high
current to open the injector, and a low current
to hold it open for the duration required. At
idle speed, the injector is pulsed at every
other inlet stroke, rather than with every
stroke as during normal operation.
The air-to-fuel mixture ratio is regulated by
the EEC IV module, based on inputs from the
various engine sensors. No adjustments to
the fuel mixture are possible.
The throttle plate control motor (mounted
on the side of the CFi unit) regulates the idle
speed by reacting to the signals sent by the
EEC IV module. The signals are calculated by
the values and information provided from the
engine sensors. When the throttle position
sensor indicates that the throttle is closed, the
module enters the idle speed mode or
dashpot mode (according to engine speed).
The module maintains the idle speed at a constant value, making minor adjustments as
necessary for different loads and conditions.
The base idle speed can only be adjusted by a
dealer or fuel injection specialist with the
necessary equipment to link up to the engine
management module.
To prevent the engine from running on (or
dieseling) when it is switched off, the EEC IV
module sends a signal to the throttle plate
control motor, to fully close the throttle plate
and return it to its preset position ready for
restarting. When the ignition is switched on
to restart the engine, the motor repositions
the throttle plate to the position required
according to the prevailing conditions. The EEC IV module is the heart of the entire
engine management system, controlling the
fuel injection, ignition and emissions control
systems. The module receives information
from various sensors to determine engine
temperature, speed and load, and the
quantity of air entering the engine. The
sensors also inform the module of throttle
position, inlet air temperature and exhaust gas
oxygen content. All the information supplied
to the module is computed and compared
with pre-set values stored in it’s memory, to
determine the required period of injection. Information on crankshaft position and
engine speed is generated by the distributor
on pre-1990 CVH engine models, or by a
crankshaft position sensor on all other
models. The inductive head of the crankshaft
position sensor runs just above the engine
flywheel and scans a series of 36 protrusions
on the flywheel periphery. As the crankshaft
rotates, the sensor transmits a pulse to the
system’s ignition module every time a
protrusion passes it. There is one missing
protrusion in the flywheel periphery at a point
corresponding to 90º BTDC. The ignition
module recognises the absence of a pulse
from the crankshaft position sensor at this
point to establish a reference mark for
crankshaft position. Similarly, the time interval
between absent pulses is used to determine
engine speed. This information is then fed to
the EEC IV module for further processing. Engine temperature information is supplied
by the coolant temperature sensor. This
component is an NTC (Negative Temperature
Coefficient) thermistor - that is, a semi-
conductor whose electrical resistance
decreases as its temperature increases. It
provides the EEC IV module with a constantly-
varying (analogue) voltage signal,
corresponding to the temperature of the
engine coolant. This is used to refine the
calculations made by the module, when
determining the correct amount of fuel
required to achieve the ideal air/fuel mixture
ratio. Inlet air temperature information is supplied
by the inlet air temperature sensor. This
component is also an NTC thermistor - see
the previous paragraph - providing the EEC IV
module with a signal corresponding to the
temperature of air passing into the engine.
4B•2 Fuel system - central fuel injection engines
1.3 Exploded view of the CFi unit
1 Fuel injector assembly
2 Fuel pressure regulator
assembly 3 Fuel feed connector
4 Intake air temperature
sensor 5 Throttle-plate control
motor
6 Throttle position sensor
7 Fuel injector wiring
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This is used to refine the calculations made by
the module, when determining the correct
amount of fuel required to achieve the ideal
air/fuel mixture ratio.A throttle position sensor is mounted on the
end of the throttle valve spindle, to provide
the EEC IV module with a constantly-varying
(analogue) voltage signal corresponding to the
throttle opening. This allows the module to
register the driver’s input when determining
the amount of fuel required by the engine. Road speed is monitored by the vehicle
speed sensor. This component is a Hall-effect
generator, mounted on the transmission’s
speedometer drive. It supplies the EEC IV
module with a series of pulses corresponding
to the vehicle’s road speed, enabling the
module to control features such as the fuel
shut-off on overrun. A manifold absolute pressure sensor
measures inlet manifold vacuum, and supplies
this information to the module for calculation
of engine load at any given throttle position. Where power steering is fitted, a pressure-
operated switch is screwed into the power
steering system’s high-pressure pipe. The
switch sends a signal to the EEC IV module to
reduce engine speed should the power
steering fluid pressure become excessively
high. Certain later engines may be fitted with a
heater in the inlet manifold. This is controlled
by the EEC IV module to ensure that, even
before the effect of the coolant heating
becomes apparent, the manifold is warmed-
up. This prevents fuel droplets condensing in
the manifold, thus improving driveability and
reducing exhaust emissions when the engine
is cold.
The oxygen sensor in the exhaust system
provides the EEC IV module with constant
feedback - “closed-loop” control - which
enables it to adjust the mixture to provide the
best possible conditions for the catalytic
converter to operate.
Precautions
Warning: Petrol is extremely
flammable - great care must be
taken when working on any part
of the fuel system. Do not
smoke or allow any naked flames or
uncovered light bulbs near the work area.
Note that gas powered domestic
appliances with pilot flames, such as
heaters, boilers and tumble dryers, also
present a fire hazard - bear this in mind if
you are working in an area where such
appliances are present. Always keep a
suitable fire extinguisher close to the work
area and familiarise yourself with its
operation before starting work. Wear eye
protection when working on fuel systems
and wash off any fuel spilt on bare skin
immediately with soap and water. Note
that fuel vapour is just as dangerous as
liquid fuel; a vessel that has just been
emptied of liquid fuel will still contain vapour and can be potentially explosive.
Petrol is a highly dangerous and volatile
liquid, and the precautions necessary
when handling it cannot be overstressed.
Many of the operations described in this
Chapter involve the disconnection of fuel
lines, which may cause an amount of fuel
spillage. Before commencing work, refer
to the above Warning and the information
in “Safety first” at the beginning of this
manual. When working with fuel system
components, pay particular attention to
cleanliness - dirt entering the fuel system
may cause blockages which will lead to
poor running.
Note: Residual pressure will remain in the fuel
lines long after the vehicle was last used,
when disconnecting any fuel line, it will be
necessary to depressurise the fuel system as
described in Section 2 .
2 Fuel system-
depressurisation
1
Note: Refer to the warning note in Section 1
before proceeding.
Warning: The following
procedure will merely relieve the
pressure in the fuel system -
remember that fuel will still be present in
the system components, and take
precautions accordingly before
disconnecting any of them.
1 The fuel system referred to in this Chapter
is defined as the fuel tank and tank-mounted
fuel pump/fuel gauge sender unit, the fuel
filter, the fuel injector, fuel pressure regulator,
and the metal pipes and flexible hoses of the
fuel lines between these components. All
these contain fuel, which will be under
pressure while the engine is running and/or
while the ignition is switched on.
2 The pressure will remain for some time after
the ignition has been switched off, and must
be relieved before any of these components is
disturbed for servicing work.
3 The simplest depressurisation method is to
disconnect the fuel pump electrical supply by
removing the fuel pump fuse (No 19) and
starting the engine; allow the engine to idle
until it dies through lack of fuel pressure. Turn
the engine over once or twice on the starter to
ensure that all pressure is released, then
switch off the ignition; do not forget to refit the
fuse when work is complete.
4 Note that, once the fuel system has been
depressurised and drained (even partially), it
will take significantly longer to restart the
engine - perhaps several seconds of cranking
- before the system is refilled and pressure
restored.
3 Fuel lines and fittings -
general information
Note: Refer to the warning note in Section 1
before proceeding.
Disconnecting and connecting
quick-release couplings
1 Quick-release couplings are employed at
many of the unions in the fuel feed and return
lines.
2 Before disconnecting any fuel system
component, relieve the residual pressure in
the system (see Section 2), and equalise tank
pressure by removing the fuel filler cap.
Warning: This procedure will
merely relieve the increased
pressure necessary for the
engine to run - remember that
fuel will still be present in the system
components, and take precautions
accordingly before disconnecting any of
them.
3 Release the protruding locking lugs on each
union, by squeezing them together and
carefully pulling the coupling apart. Use rag to
soak up any spilt fuel. Where the unions are
colour-coded, the pipes cannot be confused.
Where both unions are the same colour, note
carefully which pipe is connected to which,
and ensure that they are correctly
reconnected on refitting.
4 To reconnect one of these couplings, press
them together until the locking lugs snap into
their groove. Switch the ignition on and off
five times to pressurise the system, and check
for any sign of fuel leakage around the
disturbed coupling before attempting to start
the engine.
Checking
5 Checking procedures for the fuel lines are
included in Chapter 1.
Component renewal
6 If any damaged sections are to be renewed,
use original-equipment replacement hoses or
pipes, constructed from exactly the same
material as the section being replaced. Do not
install substitutes constructed from inferior or
inappropriate material; this could cause a fuel
leak or a fire.
7 Before detaching or disconnecting any part
of the fuel system, note the routing of all
hoses and pipes, and the orientation of all
clamps and clips. Replacement sections must
be installed in exactly the same manner.
8 Before disconnecting any part of the fuel
system, be sure to relieve the fuel system
pressure (see Section 2), and equalise tank
pressure by removing the fuel filler cap. Also
disconnect the battery negative (earth) lead -
see Chapter 5A, Section 1. Cover the fitting
being disconnected with a rag, to absorb any
fuel that may spray out.
Fuel system - central fuel injection engines 4B•3
4B
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4 Air cleaner assembly and airinlet components -
removal and refitting
1
Note: Air cleaner element renewal and air
cleaner temperature control system checks
(where applicable) are described in Chapter 1.
Air cleaner assembly
1 Disconnect the battery negative (earth) lead
(refer to Chapter 5A, Section 1).
2 Undo the retaining bolts and partially lift the
air cleaner from the CFi unit, so that the hose
and wiring connections to the underside of
the air cleaner body are accessible.
3 Note their connections and routings, then
detach the wiring and hoses from the
underside of the air cleaner.
4 Lift the air cleaner clear from the CFi unit.
5 Refit in the reverse order of removal.
6 Renew any hoses that are perished or
cracked, and ensure that all fittings are
securely and correctly reconnected.
Air inlet components
7 The air cleaner inlet spout and related
components are removed with the air cleaner
assembly as described above.
5 Accelerator cable - removal,
refitting and adjustment
1
Removal
1 Disconnect the battery negative (earth) lead
(refer to Chapter 5A, Section 1).
2 Fold back the carpet and insulation in the
driver’s footwell to gain access to the
accelerator pedal.
3 Detach the accelerator cable from the
pedal.
4 Remove the air cleaner assembly as
described in Section 4.
5 Working at the throttle housing end of the
cable, pivot the throttle quadrant by hand to
release the tension from the cable, then
detach the inner cable nipple from the throttle
lever.
6 Detach the outer cable from the
adjuster/support bracket, then remove the
cable.
Refitting and adjustment
7 Refit in the reverse order of removal. When
the cable is reconnected at each end, have an
assistant depress the accelerator, and check
that the throttle fully opens and shuts without
binding. Ensure that there is a small amount of
slack in the inner cable when the throttle is
fully released. If adjustment is required,
release the outer cable retaining clip from the
cable at the adjustment/support bracket, slide
the cable through the adjuster grommet to the
point required, then refit the retaining clip to
secure it in the set position.
6 Accelerator pedal -
removal and refitting
1
Refer to Part A, Section 5.
7 Fuel pump/fuel pressure -
checking
3
Note: Refer to the warning note in Section 1
before proceeding.
Fuel pump operation check
1 Switch on the ignition, and listen for the fuel
pump (the sound of an electric motor running,
audible from beneath the rear seats). Assuming
there is sufficient fuel in the tank, the pump
should start and run for approximately one or
two seconds, then stop, each time the ignition
is switched on. Note:If the pump runs
continuously all the time the ignition is switched
on, the electronic control system is running in
the backup (or “limp-home”) mode referred to
by Ford as “Limited Operation Strategy” (LOS).
This almost certainly indicates a fault in the
EEC IV module itself, and the vehicle should
therefore be taken to a Ford dealer for a full test
of the complete system, using the correct
diagnostic equipment; do not waste time or risk
damaging the components by trying to test the
system without such facilities.
2 Listen for fuel return noises from the fuel
pressure regulator. It should be possible to
feel the fuel pulsing in the regulator and in the
feed hose from the fuel filter.
3 If the pump does not run at all, check the
fuse, relay and wiring (see Chapter 12). Check
also that the fuel cut-off switch has not been
activated and if so, reset it.
Fuel pressure check
4 A fuel pressure gauge will be required for this
check and should be connected in the fuel line
between the fuel filter and the CFi unit, in
accordance with the gauge maker’s instructions.
5 Start the engine and allow it to idle. Note
the gauge reading as soon as the pressure
stabilises, and compare it with the figures
given for regulated fuel pressure in the
Specifications . If the pressure is high, check
for a restricted fuel return line. If the pressure
is low, renew the fuel pressure regulator. 6
Switch off the engine, and check that after
one minute, the hold pressure has not fallen
below that specified. If it has, check the seals
on the fuel injector (see Section 14) and renew
them if they appear in any way suspect. If the
seals are okay, then the fuel pressure
regulator or CFi unit are suspect.
7 Carefully disconnect the fuel pressure
gauge, depressurising the system first as
described in Section 2.
8 Run the engine, and check that there are no
fuel leaks.
8 Fuel tank - removal,
inspection and refitting
3
Proceed as described in Part A, Section 8, but
before disconnecting the battery, relieve the
residual pressure in the fuel system (see Sec-
tion 2), and equalise tank pressure by removing
the fuel filler cap. Note also that it will be
necessary to release any additional ventilation
tubes from their retaining clips, and to reposition
or remove the underbody heat shields on certain
models for access to the tank retaining bolts.
9 Fuel pump/fuel gauge
sender unit - removal and
refitting
3
Note: Refer to the warning note in Section 1
before proceeding. Ford specify the use of their
service tool 23-026 (a large box spanner with
projecting teeth to engage the fuel pump/sender
unit retaining ring’s slots) for this task. While
alternatives are possible, in view of the difficulty
experienced in removing and refitting the
pump/sender unit, it is strongly advised that the
correct tool is obtained before starting work.
Removal
1 A combined fuel pump and fuel gauge
sender unit are located in the top face of the
fuel tank. The combined unit can only be
detached and withdrawn from the tank after
the tank is released and lowered from
under the vehicle. Refer to Section 8 and
remove the fuel tank, then proceed as follows.
2 With the fuel tank removed, the
pump/sender unit can be unscrewed using
the special tool (see illustration) .
3 Withdraw the unit upwards from the tank
(see illustration) , and detach the seal ring.
9.3 Fuel pump (A) and sender unit (B)
4B•4 Fuel system - central fuel injection engines
9.2 Ford Special tool engaged on the fuel
pump/sender unit
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