1993 FORD MONDEO fuel filter location

23If using Ford’s recommended procedure,
fit new oil seals to the camshafts as
described in paragraph 5 of Section 12.
24Using the marks and notes made on
dismantling to ensure that each is refitted to
its original camshaft, refit the toothed pulleys
to the camshafts, tightening the retaining
bolts loosely (see illustration). Slip the timing
belt back onto the pulleys (refer to para-
graph 21 of Section 10) and tighten the bolts
securely - use the forked holding tool
described in paragraph 18 of Section 10.
25The remainder of the reassembly
procedure, including checking the camshaft
alignment (valve timing) and setting the timing
belt tension, is as described in paragraphs 17
to 27 of Section 10.
Removal
Note:The following text assumes that the
cylinder head will be removed with both inlet
and exhaust manifolds attached; this
simplifies the procedure, but makes it a bulky
and heavy assembly to handle - an engine
hoist will be required, to prevent the risk of
injury, and to prevent damage to any delicate
components as the assembly is removed and
refitted. If it is wished first to remove the
manifolds, proceed as described in Sections
6 and 7 of this Chapter; amend the following
procedure accordingly.1Relieve the fuel system pressure (see
Chapter 4).
2With the vehicle parked on firm level
ground, open the bonnet and disconnect the
battery negative (earth) lead - see Chapter 5,
Section 1.
3Whenever you disconnect any vacuum
lines, coolant and emissions hoses, wiring
loom connectors, earth straps and fuel lines
as part of the following procedure, always
label them clearly, so that they can be
correctly reassembled.
4Unplugging the two electrical connectors,
disconnecting the vacuum hose (where fitted)
and disconnecting the crankcase breather
hose from the cylinder head cover, remove
the complete air cleaner assembly with the air
mass meter, the resonator and the plenum
chamber (see Chapter 4).
5Equalise the pressure in the fuel tank by
removing the filler cap, then undo the fuel
feed and return lines connecting the engine to
the chassis (see Chapter 4). Plug or cap all
open fittings.
6Disconnect the accelerator cable from the
throttle linkage as described in Chapter 4 -where fitted, disconnect also the cruise control
actuator cable (see Chapter 12). Secure the
cable(s) clear of the engine/transmission.
7Unbolt the power steering high-pressure
pipe from the cylinder head rear support
plate/engine lifting eye, and from the front
support plate/pump bracket. Releasing its
wire clip, unplug the power steering pressure
switch electrical connector, then unbolt the
earth lead from the cylinder head rear support
plate/engine lifting eye.
8Remove the three screws securing the
wiring “rail” to the rear of the manifold.
Releasing its wire clip, unplug the large
electrical connector (next to the fuel pressure
regulator) to disconnect the engine wiring from
the main loom (see illustration). Unplug the
electrical connectors on each side of the
ignition coil, and the single connector from
beneath the front of the thermostat housing, to
disconnect the coil and coolant temperature
gauge sender wiring (see illustration).
9Marking or labelling them as they are
unplugged, disconnect the vacuum hoses as
follows:
(a) One from the rear of the throttle housing
(only the one hose - there is no need to
disconnect the second hose running to
the fuel pressure regulator).
(b) One from the union on the inlet manifold’s
left-hand end (see illustration).
(c) The braking system vacuum servo unit
hose (see Chapter 9 for details).
(d) Disconnect all vacuum hoses from the
Exhaust Gas Recirculation system
components - one from the EGR valve
and two from the EGR pipe. (Note that
these last two are of different sizes, as are
their pipe stubs, so that they can only be
connected the correct way round.)
10Unbolt both parts of the exhaust manifold
heat shield; unclip the coolant hose to allow the
upper part to be withdrawn. Either remove the
dipstick and tube, or swing them out of the way.
11Unscrew the single bolt securing the
pulse-air filter housing to the engine/
transmission front mounting bracket, then
disconnect its vacuum hose.
12Drain the cooling system (see Chapter 1).
13Disconnect all coolant hoses from the
thermostat housing (see illustration).
14 Cylinder head -
removal and refitting
In-car engine repair procedures 2A•17
2A
14.9 Disconnect vacuum hoses (arrowed)
as described in text14.13 Disconnect all coolant hoses
(arrowed) from thermostat housing
13.24 . . . while camshaft toothed pulleys
are refitted14.8A Release wire clip to unplug engine
wiring loom connector from inlet manifold14.8B Unplug connectors (arrowed) to
disconnect ignition coil wiring
Masking tape and/or a touch-
up paint applicator work
well for marking items.
Take instant photos, or
sketch the locations of components
and brackets.
procarmanuals.com

(a) One from the rear of the throttle housing
(only the one hose - there is no need to
disconnect the second hose running to
the fuel pressure regulator) (see
illustration).
(b) One from the union on the inlet manifold’s
left-hand end (see illustration).
(c) The braking system vacuum servo unit
hose - from the inlet manifold (see
Chapter 9 for details).
(d) Also disconnect the vacuum hoses from
the Exhaust Gas Recirculation system
components - one from the EGR valve,
two from the EGR pipe (note that these
last two are of different sizes, as are their
pipe stubs, so that they can only be
connected the correct way round).
(e) While you are there, trace the vacuum line
from the pulse-air filter housing over the
top of the transmission, and disconnect it
by pulling the plastic pipe out of the
rubber hose just beneath the bulkhead-
mounted pulse-air solenoid valve (see
illustration).
(f) Secure all these hoses so that they won’t
get damaged as the engine/transmission
is removed.
11Unbolt the engine/transmission-to-body
earth lead from the transmission’s top surface
(see illustration). Disconnect the speed-
ometer drive cable (see Chapter 12) and
secure it clear of the engine/transmission.
12Where the vehicle is fitted with manual
transmission, disconnect the clutch cable (seeChapter 8). Where automatic transmission is
fitted, disconnect the selector cable (see
Chapter 7, Part B). Secure the cable clear of
the engine/transmission.
13Marking or labelling all components as
they are disconnected (see paragraph 5
above), disconnect the engine wiring loom
from the body as follows:
(a) Starting at the left-hand side of the engine
compartment, release and unplug the
three large electrical connectors clipped
to the suspension mounting - note the
wire clips fitted to some connectors (see
illustration).
(b) Disconnect and/or release the battery-to-
starter motor wiring, noting the single
connector which must be unplugged.
(c) Unplug the electrical connector(s) to
disconnect the vehicle speed sensor,
oxygen sensor and, where fitted, the oil
level sensor wiring - unclip the connectors
to release the wiring where necessary.
(d) Work along the loom to the bulkhead,
unclipping the loom and unplugging the
various bulkhead-mounted components
connected into it, until you reach the
right-hand side of the engine
compartment (see illustration).
(e) Carefully prise the power steering fluid
reservoir upwards out of its clip on the
suspension mounting, then unscrew the
ECU connector’s retaining bolt and
unplug the connector (see illustration).
(f) Unbolt the earth lead from the right-hand
Engine removal and general engine overhaul procedures 2B•5
2B
4.13A Unplug three large electrical
connectors (arrowed) . . .4.13B . . . unplug engine wiring loom from
battery wiring and bulkhead components
(arrowed) . . .4.13C . . . and disconnect ECU wiring and
earth lead (arrowed) to release engine
wiring loom from vehicle body
4.9C . . . and the earth lead from the
cylinder head rear support plate/engine
lifting eye4.10A Disconnect vacuum hose shown
from rear of throttle housing . . .4.10B . . . vacuum hose (arrowed) from
union on left-hand end on inlet manifold . . .
4.10C . . . also brake servo hose (A), EGR
valve hose (B), EGR pipe hoses (C) - noting
their different sizes - and pulse-air filter
vacuum line (D)
4.11 Unbolt the engine/transmission-to-
body earth lead - hidden behind wiring
loom guide - from location (arrowed) on
the transmission’s top surface
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which pulley, disconnect the first cable end
nipple from the throttle actuator’s upper
pulley, then slide the cable outer upwards out
of the actuator housing. Disconnect the
second cable in the same way from the
actuator’s lower pulley.
6Working in the passenger compartment,
reach up to the top of the accelerator pedal.
Pull the end fitting and collar out of the pedal,
then release the cable inner wire through the
slot in the pedal. Tie a length of string to the
end of the cable.
7Returning to the engine compartment, pull
the cable through the bulkhead until the string
can be untied and the pedal-to-actuator cable
removed.
Refitting
8Refitting is the reverse of the removal
procedure. Use the string to draw the pedal-
to-actuator cable through the bulkhead.
Ensure that each cable end is connected to
the correct actuator pulley.
9Adjust both cables as described below.
Adjustment
Note:Both sections of the cable must be
adjusted together, even if only one has been
disturbed.
10Remove the plenum chamber (see
Section 4).
11Remove the metal clip from the adjuster
of each cable section (see illustration), and
lubricate the adjusters’ grommets with soapy
water.
12Remove any slack by pulling both cable
outers as far as possible out of their
respective adjusters.
13Unplug the TCS throttle actuator’s
electrical connector, and prise off its cover.
Lock both pulleys together by pushing a
locking pin (a pin punch or a similar tool of
suitable size) into their alignment holes.
Disconnect the actuator-to-throttle housing
cable’s end nipple from the throttle linkage.
14Have an assistant depress the accelerator
pedal fully. The pedal-to-actuator cable outer
will move back into the adjuster; hold it there,
and refit the clip.
15Connect the actuator-to-throttle housing
cable end nipple to the throttle linkage, andcheck that the cable outer’s grommet is
correctly secured in the housing bracket.
16Again have the assistant depress the
accelerator pedal fully. The actuator-to-
throttle housing cable outer will move back
into the adjuster; hold it there, and refit the
clip.
17Remove the locking pin from the pulleys.
Check that the throttle valve moves smoothly
and easily from the fully-closed to the fully-
open position and back again, as the
assistant depresses and releases the
accelerator pedal. Re-adjust the cable(s) if
required.
18When the setting is correct, refit the TCS
throttle actuator’s cover and electrical
connector, then refit the plenum chamber (see
Section 4).
1Disconnect the cable inner wire from the
pedal - see Section 5 or 6, as appropriate.
2Undo the retaining nuts and bolt, then
withdraw the pedal assembly (see
illustration).
3Refitting is the reverse of the removal
procedure. Adjust the cable(s) as described in
the relevant Section of this Chapter.
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area. Don’t work in a
garage where a natural gas-type appliance
(such as a water heater or clothes dryer)
with a pilot light is present. If you spill any
fuel on your skin, rinse it off immediately
with soap and water. When you perform
any kind of work on the fuel system, wear
safety glasses, and have a Class B type
fire extinguisher on hand.
Fuel pump operation check
1Switch 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
ECU 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 trying to test the
system without such facilities.
2Listen 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.
3If the pump does not run at all, check the
fuse, relay and wiring (see Chapter 6).
Fuel pressure check
3A fuel pressure gauge, equipped with an
adaptor to suit the Schrader-type valve on the
fuel rail pressure test/release fitting
(identifiable by its blue plastic cap, and
located on the union of the fuel feed line and
the fuel rail) is required for the following
procedure. If the Ford special tool 29-033 is
available (see Section 2), the tool can be
attached to the valve, and a conventional-type
pressure gauge attached to the tool.
4If using the service tool, ensure that its tap
is turned fully anti-clockwise, then attach it to
the valve. Connect the pressure gauge to the
service tool. If using a fuel pressure gauge
with its own adaptor, connect it in accordance
with its maker’s instructions (see illustration).
5Start the engine and allow it to idle. Note
the gauge reading as soon as the pressure
stabilises, and compare it with the pressure
listed in this Chapter’s Specifications.
(a) If the pressure is high, check for a
restricted fuel return line. If the line is
clear, renew the pressure regulator.
8 Fuel pump/fuel pressure -
check
7 Accelerator pedal -
removal and refitting
Fuel and exhaust systems 4•5
4
6.11 Location of TCS throttle actuator-to-
throttle housing cable adjuster (arrowed)7.2 Removing the accelerator pedal
assembly8.4 A fuel pressure gauge, equipped with
an adaptor to suit the Schrader-type valve
on the fuel rail pressure test/release fitting,
is needed to check fuel pressure
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(b) On Estate models, slacken the clamp
immediately above the rear anti-roll bar,
and work the hose off the filler neck stub
(see illustration).
8Unscrew the six retaining nuts, and
withdraw the exhaust system’s rear heat
shield from the underbody (see illustration).
9Support the tank with a trolley jack or
similar. Place a sturdy plank between the
support and the tank, to protect the tank.
10Unscrew the bolt at the front of each
retaining strap, and pivot them down until
they are hanging out of the way. Note the
earth lead under the left-hand strap’s bolt -
clean the mating surfaces before the tank is
refitted, so that clean, metal-to-metal contact
is ensured.
11Lower the tank enough to unclip the fuel
return pipe (coded red) from its top surface,
then disconnect the charcoal canister’s
vapour hose from the union at the top rear of
the tank (see illustration). If you have any
doubts, clearly label the fuel lines and hoses,
and their respective unions. Plug the hoses, to
prevent leakage and contamination of the fuel
system.
12Remove the tank from the vehicle,
releasing it from the filler neck stub. While the
tank is removed, unhook the retaining straps
(twist them through 90° to do so), and check
that they and their locations in the underbody
are in good condition.
13With the fuel tank removed, the filler neck
can be withdrawn. It is secured by a single
screw in the filler opening, and by two bolts to
the underbody.
14Refitting is the reverse of the removal
procedure.
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area. Don’t work in a
garage where a natural gas-type appliance(such as a water heater or clothes dryer)
with a pilot light is present. If you spill any
fuel on your skin, rinse it off immediately
with soap and water. When you perform
any kind of work on the fuel system, wear
safety glasses, and have a Class B type
fire extinguisher on hand.
1Any repairs to the fuel tank or filler neck
should be carried out by a professional who
has experience in this critical and potentially-
dangerous work. Even after cleaning and
flushing of the fuel system, explosive fumes
can remain and ignite during repair of the
tank.
2If the fuel tank is removed from the vehicle,
it should not be placed in an area where
sparks or open flames could ignite the fumes
coming out of the tank. Be especially careful
inside garages where a natural gas-type
appliance is located, because the pilot light
could cause an explosion.
Warning: The fuel system
pressure must be released before
any part of the system is
disturbed - see Section 2. Petrol
is extremely flammable, so take extra
precautions when you work on any part of
the fuel system. Don’t smoke, or allow
open flames or bare light bulbs, near the
work area. Don’t work in a garage where a
natural gas-type appliance (such as a
water heater or clothes dryer) with a pilot
light is present. If you spill any fuel on your
skin, rinse it off immediately with soap and
water. When you perform any kind of work
on the fuel system, wear safety glasses,
and have a Class B type fire extinguisher
on hand.
Note: Refer to illustrations 10.4 and 10.11 for
details.
1Remove the fuel tank (see Section 10).
2Prise the two valves out of the tank, and
remove the anti-trickle fill valve from its
mounting. Take care not to damage the valves
or the tank. Prise out the rubber seals fromthe tank openings, and renew then if they are
worn, distorted, or if either has been leaking.
3If either valve is thought to be faulty, seek
the advice of a Ford dealer as to whether they
can be renewed individually. If not, the
complete valve and pipe assembly must be
renewed.
4Refitting is the reverse of the removal
procedure. Ensure that both roll-over valves
are pressed securely into their seals, so that
there can be no fuel leaks.
1Disconnect the battery negative (earth) lead
- see Chapter 5, Section 1.
2Remove the trim panel from the left-hand
footwell.
3Peel back the sound-insulating material
from the switch, and undo its two retaining
screws (see illustration).
4Unplug the switch electrical connector, and
withdraw the switch.
5Refitting is the reverse of the removal
procedure. Ensure that the switch is reset by
depressing its red button.
These models are equipped with a
Sequential Electronically-controlled Fuel
Injection (SEFI) system. The system is
composed of three basic sub-systems: fuel
system, air induction system and electronic
control system. Note:Refer to illustrations
2.1A and 2.1B of Chapter 6 for further
information on the components of the system.
Fuel system
An electric fuel pump located inside the fuel
tank supplies fuel under pressure to the fuel
rail, which distributes fuel evenly to all
injectors. A filter between the fuel pump and
the fuel rail protects the components of the
system. A pressure regulator controls the
system pressure in relation to inlet tract
depression. From the fuel rail, fuel is injected
14 Fuel injection system/engine
management system - general
information
13 Fuel cut-off switch -
removal and refitting
12 Roll-over valves -
removal and refitting
11 Fuel tank cleaning and repair -
general information
4•8 Fuel and exhaust systems
10.8 Exhaust system must be lowered and
heat shield removed to enable fuel tank
removal - arrows show location of
retaining strap front bolts10.11 Lower fuel tank - do not distort filler
neck stub (A) - and unclip (red-coded) fuel
return pipe (B), then disconnect charcoal
canister’s vapour hose (C)13.3 Fuel cut-off switch retaining screws
(arrowed)
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Emissions control systems 6•3
6
2.1B Location of principal fuel injection, ignition and
emissions control system components 2.1A Engine management system, showing fuel injection,
ignition and emissions control sub-systems
1 ECU (Electronic Control Unit)
2 Fuel pump/fuel gauge sender
unit
3 Fuel pump relay
4 Fuel filter
5 Idle speed control valve
6 Air mass meter
7 Air cleaner assembly
8 Fuel pressure regulator
9 Fuel rail
10 Throttle potentiometer
11 Intake air temperature sensor
12 Fuel injector
13 Camshaft position sensor
14 Charcoal canister
15 Charcoal canister-purge
solenoid valve
16 Ignition coil
17 Battery
18 Ignition module - only
separate (from ECU) on
vehicles with automatic
transmission
19 Coolant temperature sensor
20 Oxygen sensor
21 Crankshaft speed/position
sensor
22 Power supply relay
23 Power steering pressure
switch24 Air conditioning compressor
clutch solenoid
25 Service connector - for octane
adjustment
26 Self-test connector - for Ford
STAR tester diagnostic
equipment
27 Diagnosis connector - for Ford
diagnostic equipment FDS
2000
28 Ignition switch
29 Fuel cut-off switch
30 Exhaust Gas Recirculation
(EGR) solenoid valve
31 Exhaust Gas Recirculation
(EGR) valve
32 Exhaust Gas Recirculation
(EGR) exhaust gas pressure
differential sensor
33 Exhaust Gas Recirculation
(EGR) pressure differential
measuring point
34 To inlet manifold
35 Pulse-air filter housing
36 Pulse-air solenoid valve
37 Air conditioning/radiator
electric cooling fan control
38 Automatic transmission
control system - where
applicable1 ECU (Electronic Control Unit)
2 Self-test, diagnosis and service connectors
(left to right)
3 Bulkhead component mounting bracket - manual
transmission - showing from left to right, (EGR) solenoid
valve, pulse-air solenoid valve and (EGR) exhaust gas
pressure differential sensor
4 Bulkhead component mounting bracket - automatic
transmission - showing from left to right, (EGR) solenoid
valve, pulse-air solenoid valve and (EGR) exhaust gas
pressure differential sensor, with separate ignition module
above
5 Throttle housing, including potentiometer
6 Idle speed control valve
7 Intake air temperature sensor
8 Air mass meter
9 Exhaust Gas Recirculation (EGR) valve
10 Coolant temperature sensor
11 Crankshaft speed/position sensor
12 Pulse-air filter housing
13 Oxygen sensor
14 Ignition coil and spark plug (HT) leads
15 Camshaft position sensor
16 Fuel injector(s)
17 Power steering pressure switch
18 Air cleaner assembly
19 Air intake tube and resonators - under left-hand front wing
20 Resonator
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constantly monitors the oxygen content of the
exhaust gas. If the percentage of oxygen in
the exhaust gas is incorrect, an electrical
signal is sent to the ECU. The ECU processes
this information, and then sends a command
to the fuel injection system, telling it to change
the air/fuel mixture; the end result is an air/fuel
mixture ratio which is constantly maintained
at a predetermined ratio, regardless of driving
conditions. This happens in a fraction of a
second, and goes on almost all the time while
the engine is running - the exceptions are that
the ECU cuts out the system and runs the
engine on values pre-programmed
(“mapped”) into its memory both while the
oxygen sensor is reaching its normal
operating temperature after the engine has
been started from cold, and when the throttle
is fully open for full acceleration.
In the event of a sensor malfunction, a
back-up circuit will take over, to provide
driveability until the problem is identified and
fixed.
Precautions
(a) Always disconnect the power by
uncoupling the battery terminals - see
Section 1 of Chapter 5 - before removing
any of the electronic control system’s
electrical connectors.
(b) When installing a battery, be particularly
careful to avoid reversing the positive and
negative battery leads.
(c) Do not subject any components of the
system (especially the ECU) to severe
impact during removal or installation.
(d) Do not be careless during fault diagnosis.
Even slight terminal contact can invalidate
a testing procedure, and damage one of
the numerous transistor circuits.
(e) Never attempt to work on the ECU, to test
it (with any kind of test equipment), or to
open its cover.
(f) If you are inspecting electronic control
system components during rainy weather,
make sure that water does not enter any
part. When washing the engine
compartment, do not spray these parts or
their electrical connectors with water.
General
The various components of the fuel, ignition
and emissions control systems (not forgetting
the same ECU’s control of sub-systems such
as the radiator cooling fan, air conditioning
and automatic transmission, where
appropriate) are so closely interlinked that
diagnosis of a fault in any one component is
virtually impossible using traditional methods.
Working on simpler systems in the past, the
experienced mechanic may well have been
able to use personal skill and knowledge
immediately to pinpoint the cause of a fault, or
quickly to isolate the fault, by elimination;however, with an engine management system
integrated to this degree, this is not likely to
be possible in most instances, because of the
number of symptoms that could arise from
even a minor fault.
So that the causes of faults can be quickly
and accurately traced and rectified, the ECU
is provided with a built-in self-diagnosis
facility, which detects malfunctions in the
system’s components. When a fault occurs,
three things happen: the ECU identifies the
fault, stores a corresponding code in its
memory, and (in most cases) runs the system
using back-up values pre-programmed
(“mapped”) into its memory; some form of
driveability is thus maintained, to enable the
vehicle to be driven to a garage for attention.
Any faults that may have occurred are
indicated in the form of three-digit codes
when the system is connected (via the built-in
diagnosis or self-test connectors, as
appropriate) to special diagnostic equipment -
this points the user in the direction of the
faulty circuit, so that further tests can pinpoint
the exact location of the fault.
Given below is the procedure that would be
followed by a Ford technician to trace a fault
from scratch. Should your vehicle’s engine
management system develop a fault, read
through the procedure and decide how much
you can attempt, depending on your skill and
experience and the equipment available to
you, or whether it would be simpler to have
the vehicle attended to by your local Ford
dealer. If you are concerned about the
apparent complexity of the system, however,
remember the comments made in the fourth
paragraph of Section 1 of this Chapter; the
preliminary checks require nothing but care,
patience and a few minor items of equipment,
and may well eliminate the majority of faults.
(a) Preliminary checks
(b) Fault code read-out *
(c) Check ignition timing and base idle
speed. Recheck fault codes to establish
whether fault has been cured or not *
(d) Carry out basic check of ignition system
components. Recheck fault codes to
establish whether fault has been cured or
not *
(e) Carry out basic check of fuel system
components. Recheck fault codes to
establish whether fault has been cured or
not *
(f) If fault is still not located, carry out system
test *
Note:Operations marked with an asterisk
require special test equipment.
Preliminary checks
Note:When carrying out these checks to
trace a fault, remember that if the fault has
appeared only a short time after any part of
the vehicle has been serviced or overhauled,
the first place to check is where that work was
carried out, however unrelated it may appear,
to ensure that no carelessly-refitted
components are causing the problem.If you are tracing the cause of a “partial”
engine fault, such as lack of performance, in
addition to the checks outlined below, check
the compression pressures (see Part A of
Chapter 2) and bear in mind the possibility
that one of the hydraulic tappets might be
faulty, producing an incorrect valve clearance.
Check also that the fuel filter has been
renewed at the recommended intervals.
If the system appears completely dead,
remember the possibility that the
alarm/inhibitor system may be responsible.
1The first check for anyone without special
test equipment is to switch on the ignition,
and to 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. If the pump runs continuously all
the time the ignition is switched on, the
electronic control system is running in the
back-up (or “limp-home”) mode referred to by
Ford as “Limited Operation Strategy” (LOS).
This almost certainly indicates a fault in the
ECU 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 trying to test
the system without such facilities.
2If the fuel pump is working correctly (or not
at all), a considerable amount of fault
diagnosis is still possible without special test
equipment. Start the checking procedure as
follows.
3Open the bonnet and check the condition
of the battery connections - remake the
connections or renew the leads if a fault is
found (Chapter 5). Use the same techniques
to ensure that all earth points in the engine
compartment provide good electrical contact
through clean, metal-to-metal joints, and that
all are securely fastened. (In addition to the
earth connection at the engine lifting eye and
that from the transmission to the
body/battery, there is one earth connection
behind each headlight assembly, and one
below the power steering fluid reservoir.)
4Referring to the information given in
Chapter 12 and in the wiring diagrams at the
back of this manual, check that all fuses
protecting the circuits related to the engine
management system are in good condition.
Fit new fuses if required; while you are there,
check that all relays are securely plugged into
their sockets.
5Next work methodically around the engine
compartment, checking all visible wiring, and
the connections between sections of the
wiring loom. What you are looking for at this
stage is wiring that is obviously damaged by
chafing against sharp edges, or against
moving suspension/transmission components
and/or the auxiliary drivebelt, by being
trapped or crushed between carelessly-
refitted components, or melted by being
forced into contact with hot engine castings,
3 Diagnosis system -
general information
6•4 Emissions control systems
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back again, as an assistant depresses the
accelerator pedal. If the valve shows any sign
of stiffness, sticking or otherwise-inhibited
movement (and the accelerator cable is
known from the previous check to be in good
condition), spray the throttle linkage with
penetrating lubricant, allow time for it to work,
and repeat the check; if no improvement is
obtained, the complete throttle housing must
be renewed (Chapter 4).
15Unclip the air cleaner cover, and check
that the air filter element and the crankcase
ventilation system filter are not clogged or
soaked. (A clogged air filter will obstruct the
intake air flow, causing a noticeable effect on
engine performance; a clogged crankcase
ventilation system filter will inhibit crankcase
“breathing”). Renew or clean the filter(s) as
appropriate; refer to the relevant Sections of
Chapter 1 for further information, if required.
Before refitting the air cleaner cover, check
that the air intake (located under the front left-
hand wing, opening behind the direction
indicator/headlight assembly) is clear. It
should be possible to blow through the intake,
or to probe it (carefully) as far as the rear of
the direction indicator light.
16Start the engine and allow it to idle.
Note:Working in the engine compartment
while the engine is running requires great care
if the risk of personal injury is to be avoided;
among the dangers are burns from contact
with hot components, or contact with moving
components such as the radiator cooling fan
or the auxiliary drivebelt. Refer to “Safety
first!” at the front of this manual before
starting, and ensure that your hands, and long
hair or loose clothing, are kept well clear of hot
or moving components at all times.
17Working from the air intake junction at the
inner wing panel, via the air cleaner assembly
and air mass meter, to the resonator, plenum
chamber, throttle housing and inlet manifold
(and including the various vacuum hoses and
pipes connected to these), check for air leaks.
Usually, these will be revealed by sucking or
hissing noises, but minor leaks may be traced
by spraying a solution of soapy water on to
the suspect joint; if a leak exists, it will be
shown by the change in engine note and the
accompanying air bubbles (or sucking-in of
the liquid, depending on the pressure
difference at that point). If a leak is found at
any point, tighten the fastening clamp and/or
renew the faulty components, as applicable.
18Similarly, work from the cylinder head, via
the manifold (and not forgetting the related
EGR and pulse-air system components) to the
tailpipe, to check that the exhaust system is
free from leaks. The simplest way of doing
this, if the vehicle can be raised and
supported safely and with complete security
while the check is made, is to temporarily
block the tailpipe while listening for the sound
of escaping exhaust gases; any leak should
be evident. If a leak is found at any point,
tighten the fastening clamp bolts and/or nuts,
renew the gasket, and/or renew the faultysection of the system, as necessary, to seal
the leak.
19It is possible to make a further check of
the electrical connections by wiggling each
electrical connector of the system in turn as
the engine is idling; a faulty connector will be
immediately evident from the engine’s
response as contact is broken and remade. A
faulty connector should be renewed to ensure
the future reliability of the system; note that
this may mean the renewal of that entire
section of the loom - see your local Ford
dealer for details.
20Switch off the engine. If the fault is not yet
identified, the next step is to check the
ignition voltages, using an engine analyser
with an oscilloscope - without such
equipment, the only tests possible are to
remove and check each spark plug in turn, to
check the spark plug (HT) lead connections
and resistances, and to check the
connections and resistances of the ignition
coil. Refer to the relevant Sections of
Chapters 1 and 5.
21The final step in these preliminary checks
would be to use an exhaust gas analyser to
measure the CO level at the exhaust tailpipe.This check cannot be made without special
test equipment - see your local Ford dealer for
details.
Fault code read-out
22As noted in the general comments at the
beginning of this Section, the preliminary
checks outlined above should eliminate the
majority of faults from the engine
management system. If the fault is not yet
identified, the next step is to connect a fault
code reader to the ECU, so that its self-
diagnosis facility can be used to identify the
faulty part of the system; further tests can
then be made to identify the exact cause of
the fault.
23In their basic form, fault code readers are
simply hand-held electronic devices, which
take data stored within an ECU’s memory and
display it when required as two- or three-digit
fault codes. The more sophisticated versions
now available can also control sensors and
actuators, to provide more effective testing;
some can store information, so that a road
test can be carried out, and any faults
encountered during the test can be displayed
afterwards.
6•6 Emissions control systems
3.26 Location and terminal identification of engine management system self-test,
diagnosis and service connectors
1 Power steering fluid reservoir
2 Diagnosis connector - for Ford diagnostic equipment FDS 2000
3 Self-test connector - for fault code read-out - pin 17 is output terminal, pin 48 is input
terminal, pin 40/60 is earth
4 Service connector - for octane adjustment
5 Plug-in bridge - to suit 95 RON fuel
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