1993 FORD MONDEO dead battery

specifications were available from Ford, but a
typical reading would be in excess of 12 bars.
All cylinders should produce very similar
pressures; any difference greater than 10%
indicates the existence of a fault. Note that the
compression should build up quickly in a
healthy engine; low compression on the first
stroke, followed by gradually-increasing
pressure on successive strokes, indicates worn
piston rings. A low compression reading on the
first stroke, which does not build up during
successive strokes, indicates leaking valves or a
blown head gasket (a cracked head could also
be the cause). Deposits on the undersides of the
valve heads can also cause low compression.
8If the pressure in any cylinder is
considerably lower than the others, introduce
a teaspoonful of clean oil into that cylinder
through its spark plug hole, and repeat the
test.
9If the addition of oil temporarily improves
the compression pressure, this indicates that
bore or piston wear is responsible for the
pressure loss. No improvement suggests that
leaking or burnt valves, or a blown head
gasket, may be to blame.
10A low reading from two adjacent cylinders
is almost certainly due to the head gasket
having blown between them; the presence of
coolant in the engine oil will confirm this.
11If one cylinder is about 20 percent lower
than the others and the engine has a slightly
rough idle, a worn camshaft lobe or faulty
hydraulic tappet could be the cause.
12If the compression is unusually high, the
combustion chambers are probably coated
with carbon deposits. If this is the case, the
cylinder head should be removed and
decarbonised.
13On completion of the test, refit the spark
plugs, then reconnect the ignition system and
fuel pump.
General
1Top Dead Centre (TDC) is the highest point
in its travel up-and-down its cylinder bore
that each piston reaches as the crankshaftrotates. While each piston reaches TDC both
at the top of the compression stroke and
again at the top of the exhaust stroke, for the
purpose of timing the engine, TDC refers to
the piston position (usually No 1 piston) at the
top of its compression stroke.
2It is useful for several servicing procedures
to be able to position the engine at TDC.
3No 1 piston and cylinder are at the right-
hand (timing belt) end of the engine (right-
and left-hand are always quoted as seen from
the driver’s seat). Note that the crankshaft
rotates clockwise when viewed from the
right-hand side of the vehicle.
Locating TDC
4Remove all the spark plugs (Chapter 1).
5Disconnect both battery leads - see
Chapter 5, Section 1 - unless the starter
motor is to be used to turn the engine.
6Apply the handbrake and ensure that the
transmission is in neutral, then jack up the
front right-hand side of the vehicle and
support on an axle stand. Remove the
roadwheel.
7Remove the auxiliary drivebelt cover (see
Chapter 1) to expose the crankshaft pulley
and timing marks.
8It is best to rotate the crankshaft using a
spanner applied to the crankshaft pulley bolt;
however, it is possible also to use the starter
motor (switched on either by an assistant
using the ignition key, or by using a remote
starter switch) to bring the engine close to
TDC, then finish with a spanner. If the starter
is used, be sure to disconnect the battery
leads immediately it is no longer required.
9Note the two pairs of notches in the inner
and outer rims of the crankshaft pulley. In the
normal direction of crankshaft rotation
(clockwise, seen from the right-hand side of the
vehicle) the first pair of notches are irrelevant to
the vehicles covered in this manual, while the
second pair indicate TDC when aligned with
the rear edge of the raised mark on the sump.
Rotate the crankshaft clockwise until the
second pair of notches align with the edge of
the sump mark; use a straight edge extended
out from the sump if greater accuracy is
required (see illustrations).10Nos 1 and 4 cylinders are now at TDC,
one of them on the compression stroke.
Remove the oil filler cap; if No 4 cylinder
exhaust cam lobe is pointing to the rear of the
vehicle and slightly downwards, it is No 1
cylinder that is correctly positioned. If the
lobe is pointing horizontally forwards, rotate
the crankshaft one full turn (360°) clockwise
until the pulley notches align again, and the
lobe is pointing to the rear and slightly down.
No 1 cylinder will then be at TDC on the
compression stroke.
11Once No 1 cylinder has been positioned
at TDC on the compression stroke, TDC for
any of the other cylinders can then be located
by rotating the crankshaft clockwise 180° at a
time and following the firing order (see
Specifications).
12An alternative method of locating TDC is
to remove the cylinder head cover (see
Section 5) and to rotate the crankshaft
(clockwise, as described in paragraph 8
above) until the inlet valves for the cylinder
concerned have opened and just closed
again. Insert a length of wooden dowel
(approximately 150 mm/6 in long) or similar
into the spark plug hole until it rests on the
piston crown, and slowly further rotate the
crankshaft (taking care not to allow the dowel
to be trapped in the cylinder) until the dowel
stops rising - the piston is now at the top of
its compression stroke, and the dowel can be
removed.
13There is a “dead” area around TDC (as
the piston stops rising, pauses and then
begins to descend) which makes difficult the
exact location of TDC by this method; if
accuracy is required, either establish carefully
the exact mid-point of the dead area, or refer
to the timing marks (paragraph 9 above).
1Unplug the two electrical connectors and
disconnect the vacuum hose (where fitted),
then remove the air cleaner assembly cover
with the air mass meter, the resonator and the
plenum chamber (see Chapter 4).
2Disconnect the accelerator cable from the
5 Cylinder head cover-
removal and refitting
4 Top Dead Centre (TDC) for
No 1 piston - locating
2A•6 In-car engine repair procedures
4.9A Do not use crankshaft pulley’s first
pair of notches “A” - align second pair of
notches “B” with raised rib on sump “C” . . .4.9B . . . using a straight edge extended
out from the sump (arrowed) if greater
accuracy is required5.4 Disconnecting crankcase breather
hose from cylinder head cover union
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1With the vehicle parked on firm level
ground, open the bonnet and disconnect the
battery negative (earth) lead - see Chapter 5,
Section 1 (see illustration).
2Unbolt the power steering high-pressure
pipe from the cylinder head rear support
plate/engine lifting eye, and from the front
support plate/pump bracket.
3Unscrew the six nuts securing the
engine/transmission right-hand mounting
bracket, then withdraw the bracket.
4Slacken the water pump pulley bolts.5Remove the cylinder head cover (see
Section 5).
6Remove the spark plugs, covering their
holes with clean rag, to prevent dirt or other
foreign bodies from dropping in (see Chap-
ter 1).
7Remove the auxiliary drivebelt (see Chap-
ter 1).
8Rotate the crankshaft clockwise until the
second pair of notches in the pulley rim align
with the edge of the sump mark, so that Nos
1 and 4 cylinders are at TDC (see Section 4).9Unbolt and remove the water pump pulley
and the auxiliary drivebelt idler pulley.
10Obtain Ford service tool 21-162, or
fabricate a substitute from a strip of metal
5 mm thick (while the strip’s thickness is
critical, its length and width are not, but
should be approximately 180 to 230 mm by
20 to 30 mm). Check that Nos 1 and 4
cylinders are at Top Dead Centre (TDC) - No 1
on the compression stroke - by resting this
tool on the cylinder head mating surface, and
sliding it into the slot in the left-hand end of
both camshafts (see illustration). The tool
should slip snugly into both slots while resting
on the cylinder head mating surface; if one
camshaft is only slightly out of alignment, it is
permissible to use an open-ended spanner to
rotate the camshaft gently and carefully until
the tool will fit.
11If both camshaft slots (they are machined
significantly off-centre) are below the level of
the cylinder head mating surface, rotate the
crankshaft through one full turn clockwise
and fit the tool again; it should now fit as
described in the previous paragraph.
12With the camshaft aligning tool remaining
in place, remove the crankshaft pulley. Do not
use the locked camshafts to prevent the
crankshaft from rotating - use only the locking
methods described in Section 8.
13Remove the timing belt lower and middle
covers (see Section 9).
14With the camshaft aligning tool still in
place, slacken the tensioner bolt, and use an
Allen key inserted into its centre to rotate the
tensioner clockwise as far as possible away
from the belt; retighten the bolt to secure the
tensioner clear of the timing belt (see
illustration).
15If the timing belt is to be re-used, use
white paint or similar to mark its direction of
rotation, and note from the manufacturer’s
markings which way round it is fitted.
Withdraw the belt (see illustration). Do not
rotate the crankshaft until the timing belt is
refitted.
16If the belt is being removed for reasons
other than routine renewal, check it carefully
for any signs of uneven wear, splitting, cracks
(especially at the roots of the belt teeth) or
In-car engine repair procedures 2A•11
2A
10.10 Fit camshaft aligning tool to ensure
engine is locked with Nos 1 and 4 cylinders
at TDC10.14 Slacken tensioner bolt, and use
Allen key to rotate tensioner away from
timing belt . . .10.15 . . . then withdraw timing belt
10.1 Timing belt and cover details
1 Timing belt upper cover
2 Inlet camshaft toothed pulley
3 Exhaust camshaft toothed pulley
4 Timing belt
5 Timing belt tensioner
6 Crankshaft toothed pulley
7 Timing belt middle cover
8 Timing belt lower cover
9 Crankshaft pulley
10 Water pump pulley
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General information
The engine electrical systems include all
ignition, charging and starting components.
Because of their engine-related functions,
these components are discussed separately
from body electrical devices such as the
lights, the instruments, etc (which are
included in Chapter 12).
Precautions
Always observe the following precautions
when working on the electrical system:
(a) Be extremely careful when servicing
engine electrical components. They are
easily damaged if checked, connected or
handled improperly.
(b) Never leave the ignition switched on for
long periods of time when the engine is
not running.
(c) Don’t disconnect the battery leads while
the engine is running.
(d) Maintain correct polarity when connecting
a battery lead from another vehicle during
jump starting - see the “Booster battery
(jump) starting” section at the front of this
manual.
(e) Always disconnect the negative lead first,
and reconnect it last, or the battery may
be shorted by the tool being used to
loosen the lead clamps (see illustration).
It’s also a good idea to review the safety-
related information regarding the engine
electrical systems located in the “Safety first!”
section at the front of this manual, before
beginning any operation included in this Chapter.
Battery disconnection
Several systems fitted to the vehicle require
battery power to be available at all times, either
to ensure their continued operation (such as
the clock) or to maintain control unit memories
(such as that in the engine management
system’s ECU) which would be wiped if the
battery were to be disconnected. Whenever thebattery is to be disconnected therefore, first
note the following, to ensure that there are no
unforeseen consequences of this action:
(a) First, on any vehicle with central locking, it
is a wise precaution to remove the key
from the ignition, and to keep it with you,
so that it does not get locked in if the
central locking should engage accidentally
when the battery is reconnected!
(b) The engine management system’s ECU will
lose the information stored in its memory -
referred to by Ford as the “KAM” (Keep-
Alive Memory) - when the battery is
disconnected. This includes idling and
operating values, and any fault codes
detected - in the case of the fault codes, if it
is thought likely that the system has
developed a fault for which the
corresponding code has been logged, the
vehicle must be taken to a Ford dealer for
the codes to be read, using the special
diagnostic equipment necessary for this (see
Chapter 6). Whenever the battery is
disconnected, the information relating to idle
speed control and other operating values will
have to be re-programmed into the unit’s
memory. The ECU does this by itself, but
until then, there may be surging, hesitation,
erratic idle and a generally inferior level of
performance. To allow the ECU to relearn
these values, start the engine and run it as
close to idle speed as possible until it
reaches its normal operating temperature,
then run it for approximately two minutes at
1200 rpm. Next, drive the vehicle as far as
necessary - approximately 5 miles of varied
driving conditions is usually sufficient - to
complete the relearning process.
(c) If the battery is disconnected while the
alarm system is armed or activated, the
alarm will remain in the same state when
the battery is reconnected. The same
applies to the engine immobiliser system
(where fitted).
(d) If a trip computer is in use, any
information stored in memory will be lost.
(e) If a Ford “Keycode” audio unit is fitted,
and the unit and/or the battery is
disconnected, the unit will not function
again on reconnection until the correct
security code is entered. Details of thisprocedure, which varies according to the
unit and model year, are given in the
“Ford Audio Systems Operating Guide”
supplied with the vehicle when new, with
the code itself being given in a “Radio
Passport” and/or a “Keycode Label” at
the same time. Ensure you have the
correct code before you disconnect the
battery. For obvious security reasons, the
procedure is not given in this manual. If
you do not have the code or details of the
correct procedure, but can supply proof
of ownership and a legitimate reason for
wanting this information, the vehicle’s
selling dealer may be able to help.
Devices known as “memory-savers” (or
“code-savers”) can be used to avoid some of
the above problems. Precise details vary
according to the device used. Typically, it is
plugged into the cigarette lighter, and is
connected by its own wires to a spare battery;
the vehicle’s own battery is then disconnected
from the electrical system, leaving the
“memory-saver” to pass sufficient current to
maintain audio unit security codes and ECU
memory values, and also to run permanently-
live circuits such as the clock, all the while
isolating the battery in the event of a short-
circuit occurring while work is carried out.
Warning: Some of these devices
allow a considerable amount of
current to pass, which can mean
that many of the vehicle’s systems are still
operational when the main battery is
disconnected. If a “memory-saver” is used,
ensure that the circuit concerned is
actually “dead” before carrying out any
work on it!
Note:See also the relevant Sections of
Chapter 1.
1Disconnect the battery leads, negative
(earth) lead first - see Section 1.
2Remove the battery hold-down clamp (see
illustrations).
3Lift out the battery. Be careful - it’s heavy.
4While the battery is out, inspect the tray for
corrosion (see Chapter 1).
2 Battery- removal and refitting
1 General information,
precautions and battery
disconnection
5•2 Engine electrical systems
1.2 Always disconnect battery - negative
(earth) lead first - to prevent the possibility
of short-circuits2.2A Unscrew hold-down nuts (one of two
arrowed) . . .2.2B . . . and withdraw hold-down clamp
to release battery
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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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