1993 FORD MONDEO spark plugs replace

This Chapter is designed to help the home
mechanic maintain the Ford Mondeo models
for peak performance, economy, safety and
long life.
On the following pages are Sections
dealing specifically with each item on the
maintenance schedule. Visual checks,
adjustments, component replacement and
other helpful items are included. Refer to the
accompanying illustrations of the engine
compartment and the underside of the vehicle
for the location of various components.
Servicing your Mondeo in accordance with
the mileage/time maintenance schedule and
the following Sections will provide it with a
planned maintenance programme, which
should result in a long and reliable service life.
This is a comprehensive plan, so maintaining
some items but not others at the specified
service intervals will not produce the same
results.
As you service your Mondeo, you will
discover that many of the procedures can -
and should - be grouped together, because of
the nature of the particular procedure you’re
performing, or because of the close proximity
to one another of two otherwise-unrelated
components.
For example, if the vehicle is raised for anyreason, you should inspect the exhaust,
suspension, steering and fuel systems while
you’re under the vehicle. When you’re
checking the tyres, it makes good sense to
check the brakes and wheel bearings,
especially if the roadwheels have already
been removed.
Finally, let’s suppose you have to borrow or
hire a torque wrench. Even if you only need to
tighten the spark plugs, you might as well
check the torque of as many critical fasteners
as time allows.
The first step of this maintenance
programme is to prepare yourself before the
actual work begins. Read through all the
Sections which are relevant to the procedures
you’re planning to carry out, then make a list
of, and gather together, all the parts and tools
you will need to do the job. If it looks as if you
might run into problems during a particular
segment of some procedure, seek advice
from your local parts man or dealer service
department.
Ford state that, where antifreeze to
specification ESD-M97B-49-A (the type with
which the vehicle’s cooling system would
have been filled on production at the factory)
is used, it will last the lifetime of the vehicle.This is subject to it being used in the
recommended concentration, unmixed with
any other type of antifreeze or additive, and
topped-up when necessary using only that
antifreeze mixed 50/50 with clean water. If any
other type of antifreeze is added, the lifetime
guarantee no longer applies; to restore the
lifetime protection, the system must be
drained and thoroughly reverse-flushed
before fresh coolant mixture is poured in.
If the vehicle’s history (and therefore the
quality of the antifreeze in it) is unknown,
owners who wish to follow Ford’s
recommendations are advised to drain and
thoroughly reverse-flush the system, as
outlined in Section 28, before refilling with
fresh coolant mixture. If the appropriate
quality of antifreeze is used, the coolant can
then be left for the life of the vehicle.
If any antifreeze other than Ford’s is to be
used, the coolant must be renewed at regular
intervals to provide an equivalent degree of
protection; the conventional recommendation
is to renew the coolant every two years.
The above assumes the use of a mixture (in
exactly the specified concentration) of clean,
soft water and of antifreeze to Ford’s
specification or equivalent. It is also assumed
that the cooling system is maintained in a
scrupulously-clean condition, by ensuring that
only clean coolant is added on topping-up,
and by thorough reverse-flushing whenever
the coolant is drained (Section 28).
2 Coolant renewal
1 Introduction
1•6Weekly checks
Weekly checks
General
1Fluids are an essential part of the
lubrication, cooling, braking and other
systems. Because these fluids gradually
become depleted and/or contaminated during
normal operation of the vehicle, they must be
periodically replenished. See “Lubricants and
fluids and capacities”at the beginning of this
Chapter before adding fluid to any of the
following components. Note:The vehicle
must be on level ground before fluid levels can
be checked.
Engine oil
2The engine oil level is checked with a
dipstick located at the front of the engine; it
can be identified by its yellow/black plastic
grip (see illustration). The dipstick extends
through a metal tube, from which it protrudes
down into the sump at the bottom of the
engine.
3The oil level should be checked before the
vehicle is driven, or about 5 minutes after the
engine has been switched off.4Pull the dipstick from the tube, and wipe all
the oil from the end with a clean rag or paper
towel; note the dipstick’s maximum and
minimum levels, indicated by notches (seeillustration). Insert the clean dipstick all the way
back into its metal tube, and pull it out again.
Observe the oil on the end of the dipstick; its
level should be between these two notches.
5Do not allow the level to drop below the
minimum level notch, or oil starvation may
cause engine damage. Conversely, overfilling
the engine (adding oil above the maximum
level notch) may cause oil-fouled spark plugs,
oil leaks or oil seal failures.
6The yellow/black plastic oil filler cap is
screwed into the left-hand front end of the
3 Fluid level checks
3.2 The engine oil dipstick (arrowed) is
located at the front of the engine - note
yellow/black plastic grip
3.4 The oil level should be at or near the
maximum level notch (A) - if not, add
enough oil to correct the level. It takes
approximately 0.5 to 1.0 litre of oil to raise
the level from the minimum level notch (B)
to the maximum
If the level is checked
immediately after driving the
vehicle, some of the oil will
remain in the engine upper
components, producing an inaccurate
dipstick reading.
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5Check all fluid reservoirs, filler caps, drain
plugs and fittings etc, looking for any signs of
leakage of oil, transmission and/or brake
hydraulic fluid, coolant and power steering
fluid. If the vehicle is regularly parked in the
same place, close inspection of the ground
underneath it will soon show any leaks; ignore
the puddle of water which will be left if the air
conditioning system is in use. As soon as a
leak is detected, its source must be traced
and rectified. Where oil has been leaking for
some time, it is usually necessary to use a
steam cleaner, pressure washer or similar, to
clean away the accumulated dirt, so that the
exact source of the leak can be identified.
Vacuum hoses
6It’s quite common for vacuum hoses,
especially those in the emissions system, to
be colour-coded, or to be identified by
coloured stripes moulded into them. Various
systems require hoses with different wall
thicknesses, collapse resistance and
temperature resistance. When renewing
hoses, be sure the new ones are made of the
same material.
7Often the only effective way to check a
hose is to remove it completely from the
vehicle. If more than one hose is removed, be
sure to label the hoses and fittings to ensure
correct installation.
8When checking vacuum hoses, be sure to
include any plastic T-fittings in the check.
Inspect the fittings for cracks, and check the
hose where it fits over the fitting for distortion,
which could cause leakage.
9A small piece of vacuum hose (quarter-inch
inside diameter) can be used as a
stethoscope to detect vacuum leaks. Hold
one end of the hose to your ear, and probe
around vacuum hoses and fittings, listening
for the “hissing” sound characteristic of a
vacuum leak.
Warning: When probing with the
vacuum hose stethoscope, be
very careful not to come into
contact with moving engine
components such as the auxiliary
drivebelt, radiator electric cooling fan, etc.
Fuel hoses
Warning: There are certain
precautions which must be taken
when inspecting or servicing fuel
system components. Work in a well-
ventilated area, and do not allow open
flames (cigarettes, appliance pilot lights,
etc.) or bare light bulbs near the work
area. Mop up any spills immediately, and
do not store fuel-soaked rags where they
could ignite.
10Check all fuel hoses for deterioration and
chafing. Check especially for cracks in areas
where the hose bends, and also just before
fittings, such as where a hose attaches to the
fuel filter.
11High-quality fuel line, usually identified by
the word “Fluoroelastomer” printed on thehose, should be used for fuel line renewal.
Never, under any circumstances, use
unreinforced vacuum line, clear plastic tubing
or water hose for fuel lines.
12Spring-type clamps are commonly used
on fuel lines. These clamps often lose their
tension over a period of time, and can be
“sprung” during removal. Replace all
spring-type clamps with screw clamps
whenever a hose is replaced.
Metal lines
13Sections of metal piping are often used
for fuel line between the fuel filter and the
engine. Check carefully to be sure the piping
has not been bent or crimped, and that cracks
have not started in the line.
14If a section of metal fuel line must be
renewed, only seamless steel piping should
be used, since copper and aluminium piping
don’t have the strength necessary to
withstand normal engine vibration.
15Check the metal brake lines where they
enter the master cylinder and ABS hydraulic
unit (if used) for cracks in the lines or loose
fittings. Any sign of brake fluid leakage calls
for an immediate and thorough inspection of
the brake system.
1With the vehicle parked on level ground,
apply the handbrake firmly and open the
bonnet. Using an inspection light or a small
electric torch, check all visible wiring within
and beneath the engine compartment.
2What you are looking for 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 the
hot engine castings, coolant pipes, etc. In
almost all cases, damage of this sort is
caused in the first instance by incorrect
routing on reassembly after previous work has
been carried out.
3Depending on the extent of the problem,
damaged wiring may be repaired by rejoining
the break or splicing-in a new length of wire,
using solder to ensure a good connection,
and remaking the insulation with adhesive
insulating tape or heat-shrink tubing, as
appropriate. If the damage is extensive, given
the implications for the vehicle’s future
reliability, the best long-term answer may well
be to renew that entire section of the loom,
however expensive this may appear.
4When the actual damage has been
repaired, ensure that the wiring loom is re-
routed correctly, so that it is clear of other
components, and not stretched or kinked, and
is secured out of harm’s way using the plastic
clips, guides and ties provided.
5Check all electrical connectors, ensuringthat they are clean, securely fastened, and
that each is locked by its plastic tabs or wire
clip, as appropriate. If any connector shows
external signs of corrosion (accumulations of
white or green deposits, or streaks of “rust”),
or if any is thought to be dirty, it must be
unplugged and cleaned using electrical
contact cleaner. If the connector pins are
severely corroded, the connector must be
renewed; note that this may mean the renewal
of that entire section of the loom - see your
local Ford dealer for details.
6If the cleaner completely removes the
corrosion to leave the connector in a
satisfactory condition, it would be wise to
pack the connector with a suitable material
which will exclude dirt and moisture,
preventing the corrosion from occurring
again; a Ford dealer may be able to
recommend a suitable product.
7Check the condition of the battery
connections - remake the connections or
renew the leads if a fault is found (see Chap-
ter 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 are
one or two earth points behind each headlight
assembly, and one below the power steering
fluid reservoir.)
8Refer to Section 31 for details of spark plug
(HT) lead checks.
Warning: The air conditioning
system is under high pressure.
Do not loosen any fittings or
remove any components until
after the system has been discharged. Air
conditioning refrigerant must be properly
discharged into an approved type of
container, at a dealer service department
or an automotive air conditioning repair
facility capable of handling R134a
refrigerant. Always wear eye protection
when disconnecting air conditioning
system fittings.
1The following maintenance checks should
be performed on a regular basis, to ensure
that the air conditioner continues to operate at
peak efficiency:
(a) Check the auxiliary drivebelt. If it’s worn
or deteriorated, renew it (see Section 11).
(b) Check the system hoses. Look for cracks,
bubbles, hard spots and deterioration.
Inspect the hoses and all fittings for oil
bubbles and seepage. If there’s any
evidence of wear, damage or leaks, renew
the hose(s).
(c) Inspect the condenser fins for leaves,
insects and other debris. Use a “fin
14 Air conditioning system
check
13 Engine compartment wiring
check
1•15
1
Every 10 000 miles
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The cylinder head is provided with two oil
galleries, one on the inlet side and one on the
exhaust, to ensure constant oil supply to the
camshaft bearings and hydraulic tappets. A
retaining valve (inserted into the cylinder
head’s top surface, in the middle, on the inlet
side) prevents these galleries from being
drained when the engine is switched off. The
valve incorporates a ventilation hole in its
upper end, to allow air bubbles to escape
from the system when the engine is restarted.
While the crankshaft and camshaft
bearings and the hydraulic tappets receive a
pressurised supply, the camshaft lobes and
valves are lubricated by splash, as are all
other engine components.
Valve clearances - general
It is necessary for a clearance to exist
between the tip of each valve stem and the
valve operating mechanism, to allow for the
expansion of the various components as the
engine reaches normal operating
temperature.
On most older engine designs, this meant
that the valve clearances (also known as
“tappet” clearances) had to be checked and
adjusted regularly. If the clearances were
allowed to be too slack, the engine would be
very noisy, its power output would suffer, and
its fuel consumption would increase. If the
clearances were allowed to be too tight, the
engine’s power output would be reduced,
and the valves and their seats could be
severely damaged.
The engines covered in this manual,
however, employ hydraulic tappets which use
the lubricating system’s oil pressure
automatically to take up the clearance
between each camshaft lobe and its
respective valve stem. Therefore, there is no
need for regular checking and adjustment of
the valve clearances, but it is essential that
onlygood-quality oil of the recommended
viscosity and specification is used in the
engine, and that this oil is always changed at
the recommended intervals. If this advice is
not followed, the oilways and tappets may
become clogged with particles of dirt, or
deposits of burnt (inferior) engine oil, so that
the system cannot work properly; ultimately,
one or more of the tappets may fail, and
expensive repairs may be required.
On starting the engine from cold, there will
be a slight delay while full oil pressure builds
up in all parts of the engine, especially in the
tappets; the valve components, therefore,
may well “rattle” for about 10 seconds or so,
and then quieten. This is a normal state of
affairs, and is nothing to worry about,
provided that all tappets quieten quickly and
stay quiet.
After the vehicle has been standing for
several days, the valve components may
“rattle” for longer than usual, as nearly all the
oil will have drained away from the engine’s
top end components and bearing surfaces.
While this is only to be expected, care mustbe taken not to damage the engine under
these circumstances - avoid high speed
running until all the tappets are refilled with oil
and operating normally. With the vehicle
stationary, hold the engine at no more than a
fast idle speed (maximum 2000 to 2500 rpm)
for 10 to 15 seconds, or until the noise
ceases. Do not run the engine at more than
3000 rpm until the tappets are fully recharged
with oil and the noise has ceased.
If the valve components are thought to be
noisy, or if a light rattle persists from the top
end after the engine has warmed up to
normal operating temperature, take the
vehicle to a Ford dealer for expert advice.
Depending on the mileage covered and the
usage to which each vehicle has been put,
some vehicles may be noisier than others;
only a good mechanic experienced in these
engines can tell if the noise level is typical for
the vehicle’s mileage, or if a genuine fault
exists. If any tappet’s operation is faulty, it
must be renewed (Section 13).
The following major repair operations can
be accomplished without removing the
engine from the vehicle. However, owners
should note that any operation involving the
removal of the sump requires careful
forethought, depending on the level of skill
and the tools and facilities available; refer to
the relevant text for details.
(a) Compression pressure - testing.
(b) Cylinder head cover - removal and
refitting.
(c) Timing belt covers - removal and refitting.
(d) Timing belt - renewal.
(e) Timing belt tensioner and toothed pulleys
- removal and refitting.
(f) Camshaft oil seals - renewal.
(g) Camshafts and hydraulic tappets -
removal and refitting.
(h) Cylinder head - removal, overhaul and
refitting.
(i) Cylinder head and pistons -
decarbonising.
(j) Sump - removal and refitting.
(k) Crankshaft oil seals - renewal.
(l) Oil pump - removal and refitting.
(m) Piston/connecting rod assemblies -
removal and refitting (but see note below).
(n) Flywheel/driveplate - removal and
refitting.
(o) Engine/transmission mountings - removal
and refitting.
Clean the engine compartment and the
exterior of the engine with some type of
degreaser before any work is done. It will
make the job easier, and will help to keep dirt
out of the internal areas of the engine.
Depending on the components involved, it
may be helpful to remove the bonnet, to
improve access to the engine as repairs are
performed (refer to Chapter 11 if necessary).Cover the wings to prevent damage to the
paint; special covers are available, but an old
bedspread or blanket will also work.
If vacuum, exhaust, oil or coolant leaks
develop, indicating a need for component/
gasket or seal replacement, the repairs can
generally be made with the engine in the
vehicle. The intake and exhaust manifold
gaskets, sump gasket, crankshaft oil seals
and cylinder head gasket are all accessible
with the engine in place.
Exterior components such as the intake
and exhaust manifolds, the sump, the oil
pump, the water pump, the starter motor, the
alternator and the fuel system components
can be removed for repair with the engine in
place.
Since the cylinder head can be removed
without lifting out the engine, camshaft and
valve component servicing can also be
accomplished with the engine in the vehicle,
as can renewal of the timing belt and toothed
pulleys.
In extreme cases caused by a lack of
necessary equipment, repair or renewal of
piston rings, pistons, connecting rods and
big-end bearings is possible with the engine
in the vehicle. However, this practice is not
recommended, because of the cleaning and
preparation work that must be done to the
components involved, and because of the
amount of preliminary dismantling work
required - these operations are therefore
covered in Part B of this Chapter.
1When engine performance is down, or if
misfiring occurs which cannot be attributed to
the ignition or fuel systems, a compression
test can provide diagnostic clues as to the
engine’s condition. If the test is performed
regularly, it can give warning of trouble before
any other symptoms become apparent.
2The engine must be fully warmed-up to
normal operating temperature, the oil level
must be correct, the battery must be fully
charged, and the spark plugs must be
removed. The aid of an assistant will be
required also.
3Disable the ignition system by unplugging
the ignition coil’s electrical connector, and
remove fuse 14 to disconnect the fuel pump.
4Fit a compression tester to the No 1
cylinder spark plug hole - the type of tester
which screws into the plug thread is to be
preferred.
5Have the assistant hold the throttle wide
open and crank the engine on the starter
motor; after one or two revolutions, the
compression pressure should build up to a
maximum figure, and then stabilise. Record
the highest reading obtained.
6Repeat the test on the remaining cylinders,
recording the pressure developed in each.
7At the time of writing, no compression
3 Compression test -
description and interpretation
2 Repair operations possible with
the engine in the vehicle
In-car engine repair procedures 2A•5
2A
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gear linkage heat shield. Reconnect the
gearchange linkage and transmission support
rods to the transmission, adjusting the linkage
using the marks made on removal (see
Chapter 7, Part A, for details).
56Re-install the remaining components and
fasteners in the reverse order of removal.
57Add coolant, engine oil and transmission
fluids as needed (see Chapter 1).
58Run the engine, and check for proper
operation and the absence of leaks. Shut off
the engine, and recheck the fluid levels.
59Remember that, since the front suspension
subframe and steering gear have been
disturbed, the wheel alignment and steering
angles must be checked fully and carefully as
soon as possible, with any necessary
adjustments being made. This operation is best
carried out by an experienced mechanic, using
proper checking equipment; the vehicle should
therefore be taken to a Ford dealer or similarly-
qualified person for attention.
1It is much easier to dismantle and work on
the engine if it is mounted on a portable engine
stand. These stands can often be hired from a
tool hire shop. Before the engine is mounted
on a stand, the flywheel/driveplate should be
removed (Part A of this Chapter, Section 21)
so that the stand bolts can be tightened into
the end of the cylinder block/crankcase.
2If a stand is not available, it is possible to
dismantle the engine with it mounted on
blocks, on a sturdy workbench or on the floor.
Be extra-careful not to tip or drop the engine
when working without a stand.
3If you are going to obtain a reconditioned
engine, all external components must be
removed first, to be transferred to the
replacement engine (just as they will if you are
doing a complete engine overhaul yourself).
Note:When removing the external
components from the engine, pay close
attention to details that may be helpful or
important during refitting. Note the fitted
position of gaskets, seals, spacers, pins,
washers, bolts and other small items.These
external components include the following:
(a) Alternator and brackets (Chapter 5).
(b) HT leads and spark plugs (Chapter 1).
(c) Thermostat and housing (Chapter 3).
(d) Dipstick tube.
(e) Fuel injection system components
(Chapter 4).
(f) All electrical switches and sensors - refer
to the appropriate Chapter.
(g) Inlet and exhaust manifolds (Part A of this
Chapter).
(h) Oil filter (Chapter 1).
(i) Engine/transmission mounting brackets
(Part A of this Chapter, Section 22).
(j) Flywheel/driveplate (Part A of this
Chapter, Section 21).
4If you are obtaining a “short” engine (whichconsists of the engine cylinder
block/crankcase, crankshaft, pistons and
connecting rods all assembled), then the
cylinder head, sump, oil pump, and timing belt
will have to be removed also.
5If you are planning a complete overhaul, the
engine can be dismantled and the internal
components removed in the following order.
(a) Inlet and exhaust manifolds (Part A of this
Chapter).
(b) Timing belt, toothed pulleys and
tensioner, and timing belt inner cover
(Part A of this Chapter).
(c) Cylinder head (Part A of this Chapter,
Section 14).
(d) Flywheel/driveplate (Part A of this
Chapter, Section 21).
(e) Sump (Part A of this Chapter, Section 15).
(f) Oil pump (Part A of this Chapter, Sec-
tion 16).
(g) Piston/connecting rod assemblies
(Section 9).
(h) Crankshaft (Section 10).
6Before beginning the dismantling andoverhaul procedures, make sure that you have
all of the correct tools necessary. Refer to the
introductory pages at the beginning of this
manual for further information.
Note:New and reconditioned cylinder heads
are available from the manufacturers, and
from engine overhaul specialists. Due to the
fact that some specialist tools are required for
the dismantling and inspection procedures,
and new components may not be readily
available (refer to Section 1 of this Part), it may
be more practical and economical for the
home mechanic to purchase a reconditioned
head, rather than to dismantle, inspect and
recondition the original head.
1Remove the camshafts and hydraulic
tappets (Part A of this Chapter, Section 13),
being careful to store the hydraulic tappets as
described (see illustration).
6 Cylinder head - dismantling
5 Engine overhaul-
dismantling sequence
Engine removal and general engine overhaul procedures 2B•9
2B
6.1 Cylinder head components
1 Hydraulic tappet
2 Valve collets
3 Valve spring upper seat
4 Valve spring5 Valve spring lower
seat/stem oil seal
6 Oil-retaining valve
7 Engine lifting eye
8 Cylinder head gasket9 Inlet valve
10 Locating dowels
11 Exhaust valve
12 Cylinder head bolt
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5If you are renewing the battery, make sure
that you get one that’s identical, with the
same dimensions, amperage rating, cold
cranking rating, etc. Dispose of the old battery
in a responsible fashion. Most local authorities
have facilities for the collection and disposal
of such items - batteries contain sulphuric
acid and lead, and should not be simply
thrown out with the household rubbish!
6Refitting is the reverse of the removal
procedure.
Note:See also the relevant Sections of
Chapter 1.
1Periodically inspect the entire length of
each battery lead for damage, cracked or
burned insulation, and corrosion. Poor battery
lead connections can cause starting problems
and decreased engine performance.
2Check the lead-to-terminal connections at
the ends of the leads for cracks, loose wire
strands and corrosion. The presence of white,
fluffy deposits under the insulation at the lead
terminal connection is a sign that the lead is
corroded and should be renewed. Check the
terminals for distortion, missing clamp bolts,
and corrosion.
3When removing the leads, always
disconnect the negative lead first, and
reconnect it last (see Section 1). Even if only
the positive lead is being renewed, be sure to
disconnect the negative lead from the battery
first (see Chapter 1 for further information
regarding battery lead removal).
4Disconnect the old leads from the battery,
then trace each of them to their opposite
ends, and detach them from the starter
solenoid and earth terminals. Note the routing
of each lead, to ensure correct installation.
5If you are renewing either or both of the old
leads, take them with you when buying new
leads. It is vitally important that you replace
the leads with identical parts. Leads have
characteristics that make them easy to
identify: positive leads are usually red, larger
in cross-section, and have a larger-diameter
battery post clamp; earth leads are usually
black, smaller in cross-section and have a
slightly smaller-diameter clamp for the
negative post.
6Clean the threads of the solenoid or earth
connection with a wire brush to remove rust
and corrosion.
7Attach the lead to the solenoid or earth
connection, and tighten the mounting nut/bolt
securely.
8Before connecting a new lead to thebattery, make sure that it reaches the battery
post without having to be stretched.
9Connect the positive lead first, followed by
the negative lead.
General
The ignition system includes the ignition
switch, the battery, the crankshaft speed/
position sensor, the coil, the primary (low
tension/LT) and secondary (high tension/HT)
wiring circuits, and the spark plugs. On models
with automatic transmission, a separate
ignition module is also fitted, its functions
being incorporated in the ECU on models with
manual transmission. The ignition system is
controlled by the engine management
system’s Electronic Control Unit (ECU). Using
data provided by information sensors which
monitor various engine functions (such as
engine speed and piston position, intake air
mass and temperature, engine coolant
temperature, etc.), the ECU ensures a
perfectly-timed spark under all conditions (see
Chapter 6). Note:The ignition timing is under
the full control of the ECU, and cannot be
adjusted - see Section 8 for further details.
Precautions
When working on the ignition system, take
the following precautions:
(a) Do not keep the ignition switch on for more
than 10 seconds if the engine will not start.
(b) If a separate tachometer is ever required
for servicing work, consult a dealer
service department before buying a
tachometer for use with this vehicle -
some tachometers may be incompatible
with this ignition system - and always
connect it in accordance with the
equipment manufacturer’s instructions.
(c) Never connect the ignition coil terminals
to earth. This could result in damage to
the coil and/or the ECU or ignition module
(whichever is fitted).
(d) Do not disconnect the battery when the
engine is running.
(e) Make sure that the ignition module (where
fitted) is properly earthed.
(f) Refer to the warning at the beginning of
the next Section concerning HT voltage.
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is performed
involving ignition components. This not
only includes the ignition module/ECU, coil
and spark plug (HT) leads, but related
components such as electrical connectors,
tachometer and other test equipment also.Note: This is an initial check of the “ignition
part” of the main engine management system,
to be carried out as part of the preliminary
checks of the complete engine management
system (see Chapter 6).
1If the engine turns over but won’t start,
disconnect the (HT) lead from any spark plug,
and attach it to a calibrated tester (available at
most automotive accessory shops). Connect
the clip on the tester to a good earth - a bolt
or metal bracket on the engine. If you’re
unable to obtain a calibrated ignition tester,
have the check carried out by a Ford dealer
service department or similar. Any other form
of testing (such as jumping a spark from the
end of an HT lead to earth) is not
recommended, because of the risk of
personal injury, or of damage to the
ECU/ignition module (see notes above and in
Section 4).
2Crank the engine and watch the end of the
tester to see if bright blue, well-defined sparks
occur.
3If sparks occur, sufficient voltage is
reaching the plug to fire it. Repeat the check
at the remaining plugs, to ensure that all leads
are sound and that the coil is serviceable.
However, the plugs themselves may be fouled
or faulty, so remove and check them as
described in Chapter 1.
4If no sparks or intermittent sparks occur,
the spark plug lead(s) may be defective -
check them as described in Chapter 1.
5If there’s still no spark, check the coil’s
electrical connector, to make sure it’s clean
and tight. Check for full battery voltage to the
coil at the connector’s centre terminal. The
coil is earthed through the ECU - do not
attempt to check this. Check the coil itself
(see Section 6). Make any necessary repairs,
then repeat the check again.
6The remainder of the system checks should
be left to a dealer service department or other
qualified repair facility, as there is a chance
that the ECU may be damaged if tests are not
performed properly.
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is performed
involving ignition components. This not
only includes the ignition module/ECU, coil
and spark plug (HT) leads, but related
components such as electrical connectors,
tachometer and other test equipment also.
Check
1Having checked that full battery voltage is
available at the centre terminal of the coil’s
electrical connector (see Section 5),
disconnect the battery negative (earth) lead -
see Section 1.
2Unplug the coil’s electrical connector, if not
already disconnected.
6 Ignition coil -
removal and refitting
5 Ignition system - testing
4 Ignition system - general
information and precautions
3 Battery leads -
check and renewal
Engine electrical systems 5•3
5
Apply a light coat of battery
terminal corrosion inhibitor,
or petroleum jelly, to the
threads, to prevent future
corrosion.
procarmanuals.com

REF•7
Engine fails to rotate when attempting to start
m mBattery terminal connections loose or corroded (Chapter 5).
m mBattery discharged or faulty (Chapter 5).
m mBroken, loose or disconnected wiring in the starting circuit
(Chapter 5).
m mDefective starter solenoid or switch (Chapter 5).
m mDefective starter motor (Chapter 5).
m mStarter pinion or flywheel ring gear teeth loose or broken (Chap-
ter 5).
m mEngine earth strap broken or disconnected (Chapter 5).
m mAutomatic transmission not in Park/Neutral position, or selector
lever position sensor faulty (Chapter 7, Part B).
Engine rotates but will not start
m mFuel tank empty.
m mBattery discharged (engine rotates slowly) (Chapter 5).
m mBattery terminal connections loose or corroded (Chapter 5).
m mIgnition components damp or damaged (Chapters 1 and 5).
m mBroken, loose or disconnected wiring in the ignition circuit
(Chapters 1 and 5).
m mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mMajor mechanical failure (eg camshaft drive) (Chapter 2, Part A).
Engine difficult to start when cold
m
mBattery discharged (Chapter 5).
m mBattery terminal connections loose or corroded (Chapter 5).
m mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mOther ignition system fault (Chapters 1 and 5).
m mEngine management system fault (Chapters 1, 4, 5 and 6)
m mLow cylinder compressions (Chapter 2, Part A).
Engine difficult to start when hot
m
mAir filter element dirty or clogged (Chapter 1).
m mEngine management system fault (Chapters 1, 4, 5 and 6)
m mLow cylinder compressions (Chapter 2, Part A).
m mFaulty hydraulic tappet(s) (Chapter 2, Part A).
Starter motor noisy or excessively-rough in
engagement
m mStarter pinion or flywheel ring gear teeth loose or broken (Chapter 5).
m mStarter motor mounting bolts loose or missing (Chapter 5).
m mStarter motor internal components worn or damaged (Chapter 5).
Engine starts but stops immediately
m
mLoose or faulty electrical connections in the ignition circuit
(Chapters 1 and 5).
m mEngine management system fault (Chapters 1, 4, 5 and 6)
m mVacuum leak at the inlet manifold (Chapters 1, 4 and 6).
Engine idles erratically
m
mIdle speed control valve faulty (Chapter 4).
m mEngine management system fault (Chapters 1, 4, 5 and 6)
m mAir filter element clogged (Chapter 1).
m mVacuum leak at the inlet manifold or associated hoses (Chap-
ters 1, 4 and 6).
m mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mFaulty hydraulic tappet(s) (Chapter 2, Part A).
m mUneven or low cylinder compressions (Chapter 2, Part A).
m mCamshaft lobes worn (Chapter 2).
m mTiming belt incorrectly-tensioned (Chapter 2, Part A).
Engine misfires at idle speed
m
mWorn, faulty or incorrectly-gapped spark plugs (Chapter 1).
m mFaulty spark plug HT leads (Chapter 1).
m mIdle speed control valve faulty (Chapter 4).
m mIncorrect ignition timing (Chapters 5 and 6).
m mEngine management system fault (Chapters 1, 4, 5 and 6)
m mVacuum leak at the inlet manifold or associated hoses (Chap-
ters 1, 4 and 6).
m mFaulty hydraulic tappet(s) (Chapter 2, Part A).
m mUneven or low cylinder compressions (Chapter 2, Part A).
m mDisconnected, leaking or perished crankcase ventilation hoses
(Chapters 1 and 6).
Fault Finding
The vehicle owner who does his or her own maintenance according
to the recommended service schedules should not have to use this
section of the manual very often. Modern component reliability is such
that, provided those items subject to wear or deterioration are inspected
or renewed at the specified intervals, sudden failure is comparatively
rare. Faults do not usually just happen as a result of sudden failure, but
develop over a period of time. Major mechanical failures in particular are
usually preceded by characteristic symptoms over hundreds or even
thousands of miles. Those components which do occasionally fail
without warning are often small and easily carried in the vehicle.
With any fault-finding, the first step is to decide where to begin
investigations. Sometimes this is obvious, but on other occasions, a
little detective work will be necessary. The owner who makes half a
dozen haphazard adjustments or replacements may be successful in
curing a fault (or its symptoms), but will be none the wiser if the fault
recurs, and ultimately may have spent more time and money than was
necessary. A calm and logical approach will be found to be more
satisfactory in the long run. Always take into account any warning
signs or abnormalities that may have been noticed in the period
preceding the fault - power loss, high or low gauge readings, unusual
smells, etc - and remember that failure of components such as fuses
or spark plugs may only be pointers to some underlying fault.
The pages which follow provide an easy reference guide to the
more common problems which may occur during the operation of the
vehicle. These problems and their possible causes are grouped underheadings denoting various components or systems, such as Engine,
Cooling system, etc. The Chapter and/or Section which deals with the
problem is also shown in brackets. Whatever the fault, certain basic
principles apply. These are as follows:
Verify the fault. This is simply a matter of being sure that you know
what the symptoms are before starting work. This is particularly
important if you are investigating a fault for someone else, who may
not have described it very accurately.
Don’t overlook the obvious. For example, if the vehicle won’t start, is
there petrol in the tank? (Don’t take anyone else’s word on this
particular point, and don’t trust the fuel gauge either!) If an electrical
fault is indicated, look for loose or broken wires before digging out the
test gear.
Cure the disease, not the symptom. Substituting a flat battery with a
fully-charged one will get you off the hard shoulder, but if the underlying
cause is not attended to, the new battery will go the same way. Similarly,
changing oil-fouled spark plugs for a new set will get you moving again,
but remember that the reason for the fouling (if it wasn’t simply an
incorrect grade of plug) will have to be established and corrected.
Don’t take anything for granted. Particularly, don’t forget that a
“new” component may itself be defective (especially if it’s been
rattling around in the boot for months), and don’t leave components
out of a fault diagnosis sequence just because they are new or
recently fitted. When you do finally diagnose a difficult fault, you’ll
probably realise that all the evidence was there from the start.
1 Engine
Introduction
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