lock FORD SIERRA 1993 2.G Engine Electrical Systems Workshop Manual

System type
1.3 litre models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bosch inductive discharge system
1.6 litre models (except Economy) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bosch inductive discharge system
1.6 litre Economy models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ESC system with Lucas “Hall effect” distributor
1.6 litre CVH (R6A type) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distributorless controlled by EEC IV system
1.8 litre SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ESC II system with Bosch “Hall effect” distributor
1.8 litre CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ESC Hybrid system
1.8 litre CVH (R6A type) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distributorless controlled by EEC IV system
2.0 litre SOHC carburettor models up to 1985 . . . . . . . . . . . . . . . . . . . . Bosch inductive discharge system
2.0 litre SOHC carburettor models from 1985 (except P100) . . . . . . . . . ESC II system with Bosch “Hall effect” distributor
2.0 litre DOHC carburettor models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ESC II system
P100 models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bosch inductive discharge system
2.0 litre SOHC fuel injection models up to 1987 . . . . . . . . . . . . . . . . . . EEC IV system with Motorcraft “Hall effect” distributor
2.0 litre SOHC fuel injection models from 1987 . . . . . . . . . . . . . . . . . . . EEC IV system with Bosch “Hall effect” distributor
2.0 litre DOHC fuel injection models . . . . . . . . . . . . . . . . . . . . . . . . . . . EEC IV system
Coil
All models except CVH (R6A type) and 2.0 litre DOHC
Output (minimum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.0 kilovolts
Primary winding resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.72 to 0.88 ohm
Secondary winding resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4500 to 7000 ohms
1.6 and 1.8 litre CVH (R6A type)
Output (minimum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37.0 kilovolts
Primary winding resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50 ± 0.05 ohms
2.0 litre DOHC carburettor model
Output (minimum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.0 kilovolts
Primary winding resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.72 to 0.88 ohms
Secondary winding resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4500 to 8600 ohms
2.0 litre DOHC fuel injection model
Output (minimum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.0 kilovolts
Primary winding resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.72 to 0.88 ohms
Secondary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4500 to 8600 ohms
Distributor
Direction of rotor arm rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clockwise
Firing order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1- 3 - 4 - 2 (No 1 cylinder nearest timing cover)
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatically controlled by electronic module (not adjustable)
Chapter 5
Engine electrical systems
Alternator - testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Alternator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Alternator brushes - removal, inspection and refitting . . . . . . . . . . . . .7
Alternator drivebelt(s) - checking, renewal and tensioning . . . . . . . . . .5
Battery - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Battery - testing and charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Coil - testing, removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . .12
Distributor (OHC models) - removal and refitting . . . . . . . . . . . . . . . .15
Distributor cap and rotor arm (OHC models) - removal and refitting .13
Distributor components (CVH models) - removal and refitting . . . . . .14
EEC IV system components - removal and refitting . . . . . . . . . . . . . .21Electronic modules - removal and refitting . . . . . . . . . . . . . . . . . . . . .18
ESC Hybrid system components - removal and refitting . . . . . . . . . .20
ESC II system components - removal and refitting . . . . . . . . . . . . . .19
General information and precautions . . . . . . . . . . . . . . . . . . . . . . . . . .1
Ignition timing - adjustment for use with unleaded petrol . . . . . . . . .17
Ignition timing (OHC models) - adjustment . . . . . . . . . . . . . . . . . . . .16
Starter motor - brush renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Starter motor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . .8
Starter motor - testing in the vehicle . . . . . . . . . . . . . . . . . . . . . . . . . .9
Spark control system components - removal and refitting . . . . . . . .22
Spark plugs and HT leads - removal, inspection and refitting . . . . . .11
5•1
Specifications Contents
5
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty

General information
The electrical system is of the 12 volt
negative earth type, and consists of a 12 volt
battery, alternator with integral voltage
regulator, starter motor and related electrical
accessories, components and wiring. The
battery is of the low maintenance or
maintenance-free “sealed for life” type and is
charged by an alternator which is belt-driven
from the crankshaft pulley. The starter motor
is of the pre-engaged type, incorporating an
integral solenoid. On starting the solenoid
moves the drive pinion into engagement with
the flywheel ring gear before the starter motor
is energised. Once the engine has started, a
one-way clutch prevents the motor armature
being driven by the engine until the pinion
disengages from the flywheel.
The ignition system is responsible for
igniting the air/fuel mixture in each cylinder at
the correct moment in relation to engine
speed and load. A number of different ignition
systems are fitted to models within the
Sierra/P100 range, ranging from a basic
breakerless electronic system to a fully
integrated engine management system
controlling ignition and fuel injection systems.
The ignition system is based on feeding low
tension voltage from the battery to the coil
where it is converted to high tension voltage.
The high tension voltage is powerful enough
to jump the spark plug gap in the cylinders
many times a second under high compression
pressures, providing that the system is in
good condition. The low tension (or primary)
circuit consists of the battery, the lead to the
ignition switch, the lead from the ignition
switch to the low tension coil windings
(terminal + /15) and also to the supply terminal
on the electronic module, and the lead from
the low tension coil windings (terminal -/1) to
the control terminal on the electronic module.
The high tension (or secondary) circuit
consists of the high tension coil windings, the
HT (high tension) lead from the coil to the
distributor cap, the rotor arm, the HT leads to
the spark plugs, and the spark plugs.
The system functions in the following
manner. Current flowing through the low
tension coil windings produces a magnetic
field around the high tension windings. As the
engine rotates, a sensor produces an
electrical impulse which is amplified in the
electronic module and used to switch off the
low tension circuit.
The subsequent collapse of the magnetic
field over the high tension windings produces
high tension voltage which is then fed to the
relevant spark plug via the distributor cap and
rotor arm. The low tension circuit is
automatically switched on again by the
electronic module, to allow the magnetic field
to build up again before the firing of the next
spark plug. The ignition is advanced and
retarded automatically to ensure that thespark occurs at the correct instant in relation
to the engine speed and load.
To improve driveability during warm-up
conditions and to reduce exhaust emission
levels, a vacuum-operated,
temperature-sensitive spark control system is
fitted to certain vehicles.Inductive discharge system
This is the least sophisticated system fitted
to the Sierra/P100 range, and comprises a
breakerless distributor and an electronic
switching/amplifier module in addition to the
coil and spark plugs.
The electrical impulse which is required to
switch off the low tension circuit is generated
by a magnetic trigger coil in the distributor. A
trigger wheel rotates within a magnetic stator,
the magnetic field being provided by a
permanent magnet. The magnetic field across
the two poles (stator arm and trigger wheel) is
dependent on the air gap between the two
poles. When the air gap is at its minimum, the
trigger wheel arm is directly opposite the
stator arm, and this is the trigger point. As the
magnetic flux between the stator arm and
trigger wheel varies, a voltage is induced in
the trigger coil mounted below the trigger
wheel, and this voltage is sensed and then
amplified by the electronic module and used
to switch off the low tension circuit. There is
one trigger wheel arm and one stator arm for
each cylinder (4).
The ignition advance is a function of the
distributor and is controlled both mechanically
and by a vacuum operated system. The
mechanical governor mechanism consists of
two weights which move out from the
distributor shaft as the engine speed rises due
to centrifugal force. As they move outwards,
they rotate the trigger wheel relative to the
distributor shaft and so advance the spark.
The weights are held in position by two light
springs and it is the tension of the springs
which is largely responsible for correct spark
advancement.
The vacuum control consists of a
diaphragm, one side of which is connected
via a small bore hose to the carburettor or
inlet manifold and the other side to the
distributor. Depression in the inlet manifold
and/or carburettor, which varies with engine
speed and throttle position, causes the
diaphragm to move, so moving the baseplate
and advancing or retarding the spark. A fine
degree of control is achieved by a spring in
the diaphragm assembly.
ESC (Electronic Spark Control) system
This system is only fitted to early
“Economy” models, and comprises a “Hall
effect” distributor, and an ESC module, in
addition to the coil and spark plugs.
The electrical impulse which is required to
switch off the low tension circuit is generated
by a sensor in the distributor. A trigger vane
rotates in the gap between a permanent
magnet and the sensor. The trigger vane has
four cut-outs, one for each cylinder. When
one of the trigger vane cut-outs is in line with
the sensor, magnetic flux can pass betweenthe magnet and the sensor. When a trigger
vane segment is in line with the sensor, the
magnetic flux is diverted through the trigger
vane away from the sensor. The sensor
senses the change in magnetic flux and sends
an impulse to the ESC module, which
switches off the low tension circuit.
The ignition advance is a function of the
ESC module and is controlled by vacuum. The
module is connected to the inlet manifold by a
vacuum pipe, and a transducer in the module
translates the vacuum signal into electrical
voltage. From the vacuum signal, the ESC
module determines engine load, and engine
speed is determined from the interval
between impulses supplied by the distributor
sensor. The module has a range of spark
advance settings stored in its memory, and a
suitable setting is selected for the relevant
engine speed and load. The degree of
advance can thus be constantly varied to suit
the prevailing engine speed and load
conditions.
ESC II (Electronic Spark Control II)
system
1.8 and 2.0 litre SOHC carburettor models
This system is a development of the ESC
system described previously in this Section,
but it enables more accurate control of engine
operation due to the inclusion of additional
monitoring features and control outputs.
Vehicles fitted with the ESC II system have an
electric inlet manifold heater which warms the
air/fuel mixture when the engine is cold, thus
reducing the amount of fuel enrichment
required, lowering fuel consumption and
improving driveability when the engine is cold.
The heater is operated by the ESC II module
receiving information on the engine temperature
from an engine coolant temperature sensor
mounted in the inlet manifold.
On 2.0 litre SOHC models, the ESC II
module operates a carburettor stepper motor
to control the engine idle speed. Using
information on engine speed, load,
temperature and throttle position (supplied by
a switch on the carburettor), the module
operates the stepper motor to maintain a
constant idle speed. On models equipped
with automatic transmission and/or air
conditioning, additional inputs are supplied to
the module to allow it to operate the stepper
motor to compensate for the additional engine
load imposed by the automatic
transmission/air conditioning. The ESC II
module also operates a “power hold” relay
which allows the stepper motor to function
briefly after the ignition has been switched off
in order to perform an anti-run-on and
manifold ventilation cycle.
2.0 litre DOHC carburettor models
A development of the ESC II system is used
to control the operation of the engine. The
module receives information from a
crankshaft speed/position sensor (similar to
that described for the ESC Hybrid system),
except that the sensor is activated by a
toothed disc on the rear of the crankshaft,
inside the cylinder block), and an engine
coolant temperature sensor.
1General information and
precautions
Engine electrical systems 5•3
5

The ignition advance is a function of the
ESC II module, and is controlled by vacuum.
The module is connected to the carburettor
by a vacuum pipe, and a transducer in the
module translates the vacuum signal into an
electrical voltage. From the vacuum signal,
the module determines engine load; engine
speed and temperature are determined from
the crankshaft speed/position sensor and the
engine coolant temperature sensor. The
module has a range of spark advance settings
stored in its memory, and a suitable setting is
selected for the relevant engine speed, load
and temperature. The degree of advance can
thus be constantly varied to suit the prevailing
engine speed and load conditions.
ESC Hybrid (Electronic Spark Control
Hybrid) system
This system is fitted to 1.8 CVH models,
and comprises various sensors and an ESC
Hybrid module, in addition to the coil and
spark plugs. The distributor serves purely to
distribute the HT voltage to the spark plugs
and consists simply of a rotor arm mounted
directly on the end of the camshaft, and a
distributor cap.
The electrical impulse which is required to
switch off the low tension circuit is generated
by a crankshaft speed/position sensor which
is activated by a toothed wheel on the
crankshaft. The toothed wheel has 35 equally
spaced teeth with a gap in the 36th position.
The gap is used by the sensor to determine
the crankshaft position relative to TDC (top
dead centre) of No 1 piston.
Engine load information is supplied to the
ESC Hybrid module by a vacuum transducer
within the module which is connected to the
inlet manifold by a vacuum pipe. Additional
inputs are supplied by an inlet
manifold-mounted engine coolant temperature
sensor, and an air charge temperature sensor
mounted in the base of the air cleaner. The
module selects the optimum ignition advance
setting based on the information received from
the various sensors. The degree of advance
can thus be constantly varied to suit the
prevailing engine conditions.
In addition to the ignition circuit, the module
also controls an electric choke heater, and a
solenoid valve which in turn controls a throttle
damper on the carburettor. The electric choke
heater is operated by the module using
information supplied by the engine coolant
temperature sensor. The heater is used to
slow down the rate at which the choke comes
off, thereby improving driveability and overall
fuel consumption when the engine is cold. The
solenoid valve controls the vacuum supply to
the carburettor throttle damper. The throttle
damper prevents sudden closing of the throttle
during deceleration, thus maintaining
combustion of the air/fuel mixture which
reduces harmful exhaust gas emissions.
Note that there is no provision for
adjustment of ignition timing with the ESC
Hybrid system.
EEC IV (Electronic Engine Control IV)
system
2.0 litre SOHC fuel injection models
This system controls both the ignition and
fuel injection systems. The EEC IV module
receives information from a “Hall effect”
distributor sensor (similar to that described
previously in this Section for the ESC system),
an engine coolant temperature sensor
mounted in the inlet manifold, a throttle
position sensor, and an air flow meter.
Additionally, on models equipped with
automatic transmission and/or air
conditioning, additional inputs are supplied to
the module to allow it to raise the idle speed
to compensate for the additional engine load
imposed by the automatic transmission/air
conditioning. The module provides outputs to
control the fuel pump, fuel injectors, idle
speed, and ignition circuit. Using the inputs
from the various sensors, the EEC IV module
computes the optimum ignition advance, and
fuel injector pulse duration to suit the
prevailing engine conditions. This system
gives very accurate control of the engine
under all conditions, improving fuel
consumption and driveability, and reducing
exhaust gas emissions. A “limited operation
strategy” (LOS) means that the vehicle is still
driveable, albeit at reduced power and
efficiency, in the event of a failure in the
module or its sensors.
2.0 litre DOHC fuel injection models
A development of the EEC IV system is
used to control both the ignition and fuel
injection systems. The module receives
information from a crankshaft speed/position
sensor (similar to that described for the ESC
Hybrid system), except that the sensor is
activated by a toothed disc on the rear of the
crankshaft, inside the cylinder block), a
throttle position sensor, an engine coolant
temperature sensor, a fuel temperature
sensor, an air charge temperature sensor, a
manifold absolute pressure (MAP) sensor, and
a vehicle speed sensor (mounted on the
gearbox). Additionally, on models with a
catalytic converter, an additional input is
supplied to the EEC IV module from an
exhaust gas oxygen (HEGO) sensor. On
models with automatic transmission,
additional sensors are fitted to the
transmission, to inform the EEC IV module
when the transmission is in neutral, and when
the kickdown is being operated.
The module provides outputs to control the
fuel pump, fuel injectors, idle speed, ignition
system and automatic transmission.
Additionally, on models with air conditioning,
the EEC IV module disengages the air
conditioning compressor clutch when starting
the engine, and when the engine is suddenly
accelerated. On models fitted with a catalytic
converter, the EEC IV module also controls
the carbon canister-purge solenoid valve.
Using the inputs from the various sensors,
the EEC IV module computes the optimum
ignition advance, and fuel injector pulse
duration to suit the prevailing engine
conditions. A “limited operation strategy” (LOS)means that the vehicle is still driveable, albeit at
reduced power and efficiency, in the event of a
failure in the module or one of its sensors.
1.6 litre and 1.8 litre (R6A type) CVH models
A development of the EEC IV system is
used to control both the ignition and fuel
injection systems. A fully electronic
Distributorless Ignition System (DIS) is fitted,
replacing the mechanical distribution of high
tension voltage (by a rotating distributor) with
“static” solid-state electronic components.
The system selects the most appropriate
ignition advance setting for the prevailing
engine operating conditions from a three-
dimensional map of values stored in the EEC
IV control module memory. The module
selects the appropriate advance value
according to information supplied on engine
load, speed, and operating temperature from
various sensors.
The EEC IV module receives information
from a crankshaft speed/position sensor
(similar to that described for the ESC Hybrid
system), except that on 1.6 litre engines, the
sensor is activated by a toothed disc on the
flywheel), a throttle position sensor, an engine
coolant temperature sensor, an air charge
temperature sensor, a manifold absolute
pressure (MAP) sensor, a vehicle speed
sensor (mounted on the gearbox), and an
exhaust gas oxygen sensor.
The module provides outputs to control the
fuel pump, fuel injector, throttle valve control
motor, pulse-air control solenoid, carbon
canister purge solenoid (where applicable),
and the ignition system.
Using the inputs from the various sensors,
the EEC IV module computes the optimum
ignition advance and fuel injector pulse dura-
tion to suit the prevailing engine conditions. A
“limited operation strategy” (LOS) means that
the vehicle will still be driveable, albeit at
reduced power and efficiency, in the event of
a failure in the module or one of its sensors.
Precautions
General
It is necessary to take extra care when
working on the electrical system to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. In addition to the precautions
given in the “Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.
Always remove rings, watches, etc before
working on the electrical system. Even with
the battery disconnected, capacitive
discharge could occur if a component live
terminal is earthed through a metal object.
This could cause a shock or nasty burn.
Do not reverse the battery connections.
Components such as the alternator or any
other having semi-conductor circuitry could
be irreparably damaged.
If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
5•4Engine electrical systems

41Locate the brush box over the
commutator, position the brushes, then fit the
nylon cover over the brushes. Route the brush
wiring into the locating channel, then secure
the brushes in the channels with the locking
clips and springs.
42Refit the commutator end housing,
locating the rubber block in the cut-out in the
housing, then secure with the two screws.
43Refit the spacers and C-clip to the end of
the armature shaft, then fit the commutator end
housing cap and secure with the two screws.
44Reconnect the wiring to the solenoid
terminal and fit the washer and securing nut.
Nippondenso type
45With the starter motor removed from the
vehicle and cleaned, grip the unit in a vice
fitted with soft jaw protectors.
46Unscrew the retaining nut and washer and
disconnect the wiring from the terminal on the
solenoid.
47Remove the two screws securing the
commutator end housing cap and remove the
cap (see illustration).
48Remove the C-clip from the groove in the
armature shaft, and remove the spring.
49Unscrew the two bolts and washers, and
withdraw the commutator end housing.
50Withdraw the two field brushes from the
brush plate, then remove the brush plate.
51If the brushes have worn to less than the
specified minimum, renew them as a set. To
renew the brushes, cut the leads at their
midpoint and make a good soldered joint
when connecting the new brushes.
52The commutator face should be clean and
free from burnt spots. Where necessary
burnish with fine glass paper (not emery) and
wipe with a fuel-moistened cloth. 53Position the brush plate over the end of
the armature, aligning the cut-outs in the
brush plate with the loops in the field
windings. The brush plate will be positively
located when the commutator end housing
bolts are fitted.
54Fit the brushes to their locations in the
brush plate, and retain with the springs.
55Fit the commutator end housing and
secure with the two bolts and washers.
56Fit the spring and the C-clip to the end of
the armature shaft, then smear the end of the
shaft with a little lithium-based grease, and
refit the commutator end housing cap,
securing with the two screws.
57Reconnect the wiring to the solenoid
terminal and fit the washer and retaining nut.
Note: The correct functioning of the spark plugs
is vital for the correct running and efficiency of
the engine. It is essential that the plugs fitted are
appropriate for the engine, and the suitable type
is specified at the beginning of this Chapter. If
this type is used and the engine is in good
condition, the spark plugs should not need
attention between scheduled replacement
intervals. Spark plug cleaning is rarely necessary
and should not be attempted unless specialised
equipment is available as damage can easily be
caused to the firing ends.
Removal
1Where necessary, for improved access
remove the air cleaner and/or the inlet hose.
2If necessary, identify each HT lead for
position, so that the leads can be refitted to theircorrect cylinders, then disconnect the leads
from the plugs by pulling on the connectors, not
the leads. Note that the position of No 1 cylinder
HT lead in the distributor cap is marked with
either a pip, or a number “1 “.
3On 2.0 litre DOHC carburettor models, the
location of the spark plugs and the close
proximity of the carburettor makes spark plug
access difficult, particularly when removing
the plugs from cylinders 2 and 3. It is
suggested that a 3/8 inch ratchet drive spark
plug socket with rubber insert and long
extension bar is used, possibly in conjunction
with a universal joint adapter. It is also
advisable to disconnect No 3 cylinder HT lead
from the distributor first, to allow some slack
for disconnection at the spark plug.
4Clean the area around each spark plug
using a small brush, then using a plug
spanner (preferably with a rubber insert),
unscrew and remove the plugs. Cover the
spark plug holes with a clean rag to prevent
the ingress of any foreign matter.
Inspection
5The condition of the spark plugs will tell
much about the overall condition of the engine.
6If the insulator nose of the spark plug is clean
and white, with no deposits, this is indicative of
a weak air/fuel mixture, or too hot a plug. (A hot
plug transfers heat away from the electrode
slowly - a cold plug transfers it away quickly).
7If the tip and insulator nose is covered with
hard black-looking deposits, then this is
indicative that the mixture is too rich. Should
the plug be black and oily, then it is likely that
the engine is fairly worn, as well as the mixture
being too rich.
8If the insulator nose is covered with light tan
to greyish brown deposits, then the mixture is
correct and it is likely that the engine is in
good condition.
9The spark plug gap is of considerable
importance, as, if it is too large or too small,
the size of the spark and its efficiency will be
seriously impaired. The spark plug gap should
be set to the figure given in the Specifications
at the beginning of this Chapter. To set it,
measure the gap with a feeler blade, and then
bend open, or close the outer plug electrode
until the correct gap is achieved (see
illustrations). The centre electrode should
never be bent as this may crack the insulation
and cause plug failure, if nothing worse.
11Spark plugs and HT leads -
removal, inspection and
refitting
5•12Engine electrical systems
10.47 Nippondenso starter motor brush assembly
1 Yoke
2 Solenoid connecting link
3 Pole shoe
4 Rubber grommet
5 Brush
6 Brush spring
7 Brush plate8 Commutator end housing
9 Bush
10 Spring
11 C-clip
12 Commutator end housing cap
13 Commutator end housing securing
bolt
11.9a Measuring a spark plug gap using a
feeler blade

10The distributor cap (except on 1.6 and 1.8
litre CVH (R6A type) engines) and the HT
leads should be cleaned and checked at the
specified intervals. To test the HT leads,
remove them together with the distributor
cap, then connect an ohmmeter to the end of
each lead and its appropriate terminal within
the cap in turn (see illustration). If the
resistance of any lead is greater than the
maximum given in the Specifications, check
that the lead connection in the cap is good
before renewing the lead.
Refitting
11Before fitting the spark plugs, check that
the threaded connector sleeves are tight and
that the plug exterior surfaces are clean. As
the plugs incorporate taper seats also make
sure that the threads and seats are clean.
12On DOHC models before refitting thespark plugs, coat their threads with suitable
antiseize compound, taking care not to
contaminate the electrodes.
13Screw in the spark plugs by hand, then
tighten them to the specified torque. Do not
exceed the torque figure.
14Push the HT leads firmly onto the spark
plugs, and where applicable refit the air
cleaner and/or inlet hose.Testing
All models except 1.6 and 1.8 litre
CVH (R6A type)
1The coil is located on the left-hand side of
the engine compartment and is retained by a
metal strap (see illustration). It is of high
output type and the HT tower should be kept
clean at all times to prevent possible arcing.
Bosch and Femsa coils are fitted with
protective plastic covers and Polmot coils are
fitted with an internal fusible link.
2To ensure that the correct HT polarity at the
spark plugs, the LT coil leads must always be
connected correctly. The black lead must
always be connected to the terminal marked +
115, and the green lead to the terminal
marked /1. Incorrect connections can cause
poor starting, misfiring, and short spark plug
life.
3To test the coil first disconnect the LT and
HT leads. Connect an ohmmeter betweenboth LT terminals and check that the primary
winding resistance is as given in the
Specifications. Connect the ohmmeter
between the HT terminal and either LT
terminal and check that the secondary
winding resistance is as given in the
Specifications. If either winding resistance is
not as specified, the coil should be renewed.
Reconnect the LT and HT leads on
completion.
1.6 and 1.8 litre (R6A type) CVH
models
4The coil fitted to these models is located
towards the front right-hand side of the
cylinder block (see illustration).
5Testing of the coil should be entrusted to a
Ford dealer or a suitable specialist.
Removal
All models except 1.6 and 1.8 litre
CVH (R6A type)
6Disconnect the battery negative lead,
7Disconnect the LT and HT leads from the
coil (see illustration).
8Remove the securing screw(s) and detach
the coil and strap assembly from the body
panel. Note that on models with the ESC
system, the coil strap is secured by the top
ESC module securing screw. On certain
models with the ESC II or EEC IV systems, an
“octane adjustment” service lead may be
connected to one of the coil securing screws.
On 2.0 litre DOHC fuel-injected models, the
coil/ignition module heat shield must be
removed for access to the coil securing bolts.
The heat shield is secured by two screws.
Note that on certain models, an earthing lead
12Coil - testing, removal and
refitting
Engine electrical systems 5•13
5
11.10 Method of testing an HT lead with an
ohmmeter
12.4 Ignition coil (A) and suppressor (B)
viewed from under vehicle (shroud removed)12.7 Disconnecting the HT lead from the
coil
12.1 Ignition coil - CVH model. Plastic
cover arrowed
11.9c Adjusting a spark plug gap using a
special tool11.9b Measuring a spark plug gap using a
wire gauge

and/or a suppressor may be secured by one
of the coil securing bolts (see illustrations).
1.6 and 1.8 litre (R6A type) CVH
models
9Disconnect the battery negative lead.
10Remove the two securing screws, and
withdraw the plastic ignition module shroud.
11Disconnect the ignition coil wiring plug
and, where fitted, the suppressor wiring plug,
pulling on the plugs, not on the wiring (see
illustrations).
12Release the securing lugs, and disconnect
the HT leads from the coil, noting their
locations to aid refitting.
13Remove the four Torx screws, and
withdraw the coil from the cylinder block.
Refitting
14Refitting is a reversal of removal, but
ensure that all leads are securely connected.
SOHC models
1Disconnect the battery negative lead.
2Where applicable, unclip the screening can
from the top of the distributor and disconnect
the earth strap (see illustration).
3If necessary, identify each HT lead for
position, so that the leads can be refitted to
their correct cylinders, then disconnect the
leads from the spark plugs by pulling on the
connectors, not the leads. Similarly,
disconnect the HT lead from the coil. Where
applicable, slide the HT lead holder from the
clip on the camshaft cover (see illustration).
Lucas distributors
4Remove the two securing screws and lift off
the distributor cap.
5The rotor arm is a push-fit on the end of the
distributor shaft.
6Refitting is a reversal of removal, noting that
the rotor arm can only be fitted in one
position. Ensure that the HT leads are
correctly connected.
Bosch distributors
7Prise away the spring clips with a
screwdriver and lift off the distributor cap(see
illustration).On fuel injection models,
disconnect the crankcase ventilation hose
from the air inlet hose, then disconnect the air
inlet hose from the inlet manifold and the
airflow meter for improved access. 8Refitting is a reversal of removal, noting that
the rotor arm can only be fitted in one position.
Ensure that the HT leads are correctly
connected, and on fuel injection models
ensure that the air inlet hose clips are correctly
aligned (refer to illustration, Section 15,
Chapter 4, PartB).
Motorcraft distributors
9For improved access, disconnect the
crankcase ventilation hose from the air inlet
hose, then disconnect the air inlet hose from
the inlet manifold and the airflow meter for
improved access.
10Remove the two securing screws and lift
off the distributor cap (see illustration).
11Remove the two securing screws and
withdraw the rotor arm (disc) (see
illustration). Note that on some vehicles, the
rotor arm tip may be coated with silicone
grease to assist radio interference
suppression. Do not attempt to clean the
grease off if it is present. If radio interference
13Distributor cap and rotor arm
(OHC models) - removal and
refitting
5•14Engine electrical systems
12.8a Ignition coil viewed with heat shield
removed12.11a Disconnecting the coil wiring plug . . .
13.10 Removing a distributor cap securing
screw - Motorcraft distributor13.7 Securing distributor cap with spring
clip - Bosch distributor13.3 HT lead holder on camshaft cover
13.2 Unclipping the distributor screening
can - Motorcraft distributor
12.11b . . . and the suppressor wiring plug
12.8b Suppressor secured by one of the
coil securing bolts

problems are experienced, consult a Ford
dealer or an in-car entertainment specialist.
12Proceed as described in paragraph 6, but
additionally ensure that the air inlet hose clips
are correctly aligned (refer to illustration,
Section 15, Chapter 4, PartB).
DOHC models
13Disconnect the battery negative lead.
14Unclip the lower section of the distributor
shield from the upper section, then unscrew
the two securing nuts, and withdraw the
upper section of the shield from the studs on
the upper timing chain cover (see
illustrations).
15If necessary, identify each HT lead for
position, so that the leads can be refitted to
their correct cylinders, then disconnect the
leads from the spark plugs by pulling on theconnectors, not the leads. Similarly,
disconnect the HT lead from the coil, and
release it from the clip on the timing chain
cover.
16Using a suitable Torx key or socket,
unscrew the two distributor cap securing
screws, then lift off the cap.
17The rotor arm is a push-fit on the end of
the rotor shaft (see illustration).
18If desired, the rotor housing can be pulled
from the timing chain cover.
19Refitting is a reversal of removal, ensuring
that the rotor arm is pushed fully home on the
rotor shaft. Make sure that the HT leads are
fitted to their correct cylinders. Note that the
rotor arm will only fit in one position.
1The distributor fitted to the CVH engine is
unlike any conventional distributor, in that it
has no main body and no adjustments are
possible. The distributor is used purely to
distribute HT voltage to the spark plugs. To
remove the distributor components, proceed
as follows.
2Disconnect the battery negative lead.
Distributor cap
3Pull the two halves of the distributor cap
shroud apart and remove the shroud.
Disconnect the earth strap from the tag on the
timing cover (see illustration).4If necessary, identify each HT lead for
position, so that the leads can be refitted to
their correct cylinders, then disconnect the
leads from the spark plugs by pulling on the
connectors, not the leads. Unclip the HT lead
holders from their studs on the camshaft
cover (see illustration).
5Depress the two securing screws and turn
them anti-clockwise through 90º, then lift off
the distributor cap.
6Disconnect the HT lead from the coil by
pulling on the connector not the lead, and
remove the distributor cap.
7Refitting is a reversal of removal, but ensure
that the HT leads are fitted to their correct
cylinders.
Rotor arm and housing
8With the distributor cap removed as
described previously, compress the two lugs
on the rotor shaft and withdraw the rotor arm
(see illustration).
9The rotor housing can now be removed by
pulling it from the timing cover (see
illustration).
10Refitting is a reversal of removal, but note
that the rotor arm can only be fitted in one
position.
Rotor shaft
11The rotor shaft is retained by the camshaft
sprocket bolt.
12To remove and refit the rotor shaft, first
remove the timing cover and the camshaft
14Distributor components (CVH
models) - removal and refitting
Engine electrical systems 5•15
5
13.14b . . . and the upper section of the
distributor shield
14.8 Removing the rotor arm14.4 HT lead holders (arrowed) on
camshaft cover14.3 Distributor cap shroud earth strap
connection
13.17 Removing the distributor cap and
rotor arm
13.14a Unclipping the lower section . . .13.11 Removing a rotor arm (disc) securing
screw - Motorcraft distributor

sprocket bolt. Note that there is no need to
remove the timing belt or the sprockets.
Note: During production the engine ignition
timing is accurately set using a microwave
process, and sealant is applied to the
distributor clamp bolt. Removal of the
distributor should be avoided except where
excessive bearing wear has occurred due to
high mileage or during major engine overhaul.
A timing light will be required to check the
ignition timing after refitting the distributor.
All models except early
“Economy”
Removal
1Disconnect the battery negative lead.
2If necessary, identify each HT lead for
position, so that the leads can be refitted to
their correct cylinders, then disconnect the
leads from the spark plugs by pulling on the
connectors, not the leads.
3Where applicable, unclip the screening can
from the top of the distributor and disconnect
the earth strap. On fuel injection models,
disconnect the crankcase ventilation hose
from the air inlet hose, then disconnect the air
inlet hose from the inlet manifold and the
airflow meter for improved access.4Prise away the spring clips with a
screwdriver, or remove the two securing
screws, as applicable, and lift off the
distributor cap.
5Disconnect the HT lead from the coil by
pulling on the connector, not the lead, then
slide the HT lead holder from the clip on the
camshaft cover, and withdraw the distributor
cap.
6Where applicable, disconnect the vacuum
pipe from the vacuum advance unit on the
side of the distributor (see illustration).
7Using a suitable socket or spanner on the
crankshaft pulley bolt, turn the crankshaft to
bring No 1 cylinder to the firing point. If the
distributor cap is secured by clips, make sure
that the clips stay clear of the distributormoving parts. No 1 cylinder is at the firing
point when:
a)The relevant timing marks are in
alignment.
b)The tip of the rotor arm is pointing to the
position occupied by the No 1 cylinder HT
lead terminal in the distributor cap. Note
that the position of No 1 HT lead terminal
is identified by a pip or a number “1”
c)On Lucas distributors, the cut-out in the
trigger vane is aligned with the sensor
(see illustration)
d)On Bosch distributors, the tip of the rotor
arm is aligned with the scribed line on the
distributor body (where applicable,
remove rotor arm and dust cover, then
refit rotor arm to check alignment with
scribed line) (see illustration)
e)On Motorcraft distributors, the tip of the
rotor arm is aligned with a notch in the
distributor body. Mark the relevant notch
(there may be several) for reference when
refitting. Also, the leading edge of one of
the trigger vane segments is aligned with
the rib on the sensor (remove the two
securing screws and lift off the rotor arm
to view the trigger vane and sensor) (see
illustration).
8Disconnect the distributor wiring plug,
where applicable depressing the locking
tab(s). Pull on the plug, not the wiring (see
illustration).
9Make alignment marks between the
distributor body and the cylinder block.
10Scrape the sealant from the distributor
clamp bolt, then unscrew and remove the bolt
and clamp (see illustration).
11Withdraw the distributor from the cylinder
block. As the distributor is removed, the rotor
arm will turn clockwise due to the skew gear
drive. Note the new position of the rotor arm
relative to the distributor body, if necessary
making an alignment mark (some distributors
already have an alignment mark).
12Check the distributor spindle for
excessive side-to-side movement. If evident,
the distributor must be renewed, as the only
spares available are the cap, rotor arm,
module (where applicable), and driveshaft
O-ring (see illustration).
15Distributor (OHC models) -
removal and refitting
5•16Engine electrical systems
14.9 Removing the rotor housing
15.7a Lucas distributor showing trigger
vane position No 1 cylinder at firing point
A Trigger vane cut
-outB Sensor
15.8 Disconnecting distributor wiring plug
- Bosch distributor15.7c Trigger vane segment leading edge
aligned with sensor rib - Motorcraft
distributor15.7b Rotor arm tip aligned with scribed
line on distributor body - Bosch distributor
15.6 Disconnecting vacuum pipe from
vacuum advance unit - Bosch distributor

Refitting
13Commence refitting by checking that No 1
cylinder is still at the firing point. The relevant
timing marks should be aligned. If the engine
has been turned whilst the distributor has
been removed, check that No 1 cylinder is on
its firing stroke by removing the No 1 cylinder
spark plug and placing a finger over the plug
hole. Turn the crankshaft until compression
can be felt, which indicates that No 1 piston is
rising on its firing stroke. Continue turning the
crankshaft until the relevant timing marks are
in alignment.
14Turn the rotor arm to the position noted in
paragraph 11. If a new distributor is being
fitted, and no alignment marks are present,
transfer the marks from the old distributor to
the new distributor.
15Hold the distributor directly over the
aperture in the cylinder block with the
previously made marks on the distributor
body and cylinder block aligned, then lower
the distributor into position. Again, if a new
distributor is being fitted, transfer the
alignment mark from the old distributor body
to the new distributor body. As the skew gear
drive meshes, the rotor arm will turn
anti-clockwise.
16With the distributor fitted and the marks
on the distributor body and cylinder block
aligned, check that the rotor arm is positioned
as described in paragraph 7 -if not, withdraw
the distributor, re-position the driveshaft and
try again.
17Refit the clamp, then insert and tighten
the bolt. Do not fully tighten the bolt at this
stage.
18Refit the distributor wiring plug, and
where applicable reconnect the vacuum pipe,
and refit the dust cover and/or rotor arm.
19Refit the distributor cap, and reconnect
the HT leads to the spark plugs and coil.
Ensure that the leads are refitted to their
correct cylinders.
20Where applicable, refit the screening can
to the top of the distributor and reconnect the
earth strap. On fuel injection models,
reconnect the air inlet hose, ensuring that the
clips are correctly aligned (refer to illustration,
Section 15, Chapter 4, PartB).21Reconnect the battery negative lead.
22Check and if necessary adjust the ignition
timing.
Early “Economy” models
Removal
23Removal of the distributor fitted to these
models is a similar process to that described
above.
Refitting
24Turn the crankshaft to bring No 1 cylinder
to the firing point, with the 16º BTDC mark on
the crankshaft pulley aligned with the pointer
on the crankshaft front oil seal housing, as
described above.
25Fit the new distributor to the engine as
described above, then proceed as follows.
26Cut the original distributor wiring plug
from the wiring loom. Make the cut close to
the connector.
27Strip back 10 mm of insulation from each
of the wires on the wiring loom, and on the
adapter loom supplied with the new
distributor.
28Solder the adapter loom wires to the
corresponding identically coloured wires in
the main loom.
29Carefully insulate each individual soldered
joint using insulating tape, then apply tape to
cover the join between the looms.
30Fit a new distributor cap (and screening
can, where applicable), and connect the HT
leads.31Connect the adapter loom to the
distributor.
32Start the engine, and adjust the ignition
timing to the value given in the Specifications
at the beginning of this Chapter. Work as
described above whilst noting that the
vacuum pipe must be left connected.
Note: During production the ignition timing is
accurately set using a microwave process,
and sealant is applied to the distributor clamp
bolt. Because the electronic components
require no maintenance, checking the ignition
timing does not constitute part of the routine
maintenance schedule, and the procedure is
therefore only necessary after removal and
refitting of the distributor. A timing light will be
required for this procedure. For details of
ignition timing adjustment in order to operate
vehicles on unleaded petrol refer to the
appropriate Section of this Chapter.
All models except 2.0 litre DOHC
1Before checking the ignition timing, the
following conditions must be met:
a)The engine must be at normal operating
temperature
b)Where applicable, the vacuum pipe to the
distributor vacuum unit or electronic
module (as applicable) must be
disconnected from the vacuum unit or
electronic module and plugged
c)The idle speed must be below 900 rpm
(isolate “idle speed adjustment” wire if
necessary)
d)Any earthed “octane adjustment” wires
must be temporarily isolated
2Wipe clean the crankshaft pulley timing
marks and the pointer on the crankshaft front
oil seal housing. Note that two alternative
types of pulley may be fitted (see
illustration).The desired timing values are
given in the Specifications. If necessary, use
white paint or chalk to highlight the relevant
timing mark(s) (see illustration).
3Connect a stroboscope timing light to the
No 1 cylinder HT lead, following the
manufacturer’s instructions.
4With the engine idling at normal operating
temperature, point the timing light at the
marks on the crankshaft pulley, and check
that the appropriate timing mark appears
stationary in line with the timing cover pointer.
Take care not to get the timing light leads,
clothing etc tangled in the cooling fan blades
or other moving parts of the engine.
5If adjustment is necessary, stop the engine,
slacken the distributor clamp bolt, and turn
the distributor body slightly. Turn the
distributor body clockwise to retard the
ignition timing (move the timing closer to TDC)
and anti-clockwise to advance the timing.
16Ignition timing (OHC models)
- adjustment
Engine electrical systems 5•17
5
15.12 Removing distributor driveshaft O-
ring - Motorcraft distributor15.10 Unscrewing distributor clamp bolt -
Bosch distributor
16.2a Highlighted timing marks - SOHC
engine with cast crankshaft pulley

11The amount of ignition retardation
provided by earthing the wire(s) is as shown in
the table above.
12Once the ignition timing has been
retarded, the vehicle can be operated on
either leaded or unleaded petrol.
13On 2.0 litre models, if the yellow wire (“idle
speed adjustment” wire) in the service lead is
earthed, the idle speed will be raised by 75
rpm. If the vehicle already has a single yellow
fly lead connected prior to connecting the
service lead, ensure that the yellow wire in the
service lead is earthed.
14Note that some early models have
coloured “Lucar” connectors fitted in place of
the “octane adjustment” wiring plug (see
illustration). The principle for ignition timing
adjustment on these vehicles is as described
previously for vehicles with the “octane
adjustment” wiring plug.15On completion of ignition timing
adjustment, the idle speed and mixture should
be checked and adjusted as necessary.
Note: Refer to Section 1 for precautions to be
observed when working with electronic
modules.
1Disconnect the battery negative lead.
All ESC modules except ESC
(early “Economy” models)
2All modules except the ESC Hybrid module
are mounted on the left-hand side of the
engine compartment(see illustration).The
ESC Hybrid module is mounted on the
right-hand side of the engine compartment.
3Disconnect the module wiring plug by
pulling on the plug, not the wiring. On ESC IImodules, except those fitted to 1.8 litre
models from February 1987, a locking tab at
the lower end of the wiring plug must be
depressed before unhooking the upper end of
the plug from the module. On ESC II modules
fitted to 1.8 litre models from February 1987
(see illustration)and ESC Hybrid modules,
the wiring plug is secured by a screw which is
integral with the plug (see illustrations).
4Where applicable, disconnect the vacuum
pipe from the module (see illustration).
5Remove the two or three securing screws,
as applicable, and withdraw the module from
the engine compartment. Note that the top
securing screw of the ESC module also
secures the ignition coil strap.
6Refitting is a reversal of removal, but ensure
that the underside of the module and the
corresponding area of the body panel are clean.
ESC module (early “Economy”
models)
7Remove the module complete with its
securing bracket, as described above.
8Fit the new module, slightly behind the old
module position, on the flat vertical surface of
the body panel, and secure with the two
screws supplied. Note that the module must
be mounted against the flat area of the body
panel to prevent distortion of the module, and
to ensure good heat transfer from the module
to the body.
9Reconnect the module vacuum pipe.
10Connect the adapter loom supplied with
the new module between the module and the
old module’s wiring plug.
11Where applicable, refit the coil to its
original location.
18Electronic modules - removal
and refitting
Engine electrical systems 5•19
5
18.4 Disconnecting ESC II module vacuum
pipe18.3c Disconnecting ESC Hybrid module
wiring plug18.3b Disconnecting ESC II module wiring
plug
18.2 ESC module securing screws (arrowed)
A Wiring plug B Vacuum pipe18.3a ESC II module - 1.8 litre models from
February 1987
SystemDegrees of retardation
Blue wireRed wireBlue and red
wires
ESC II (except 1.8 litre)
models from February1987246
ESC II (1.8 litre models from
February 1987)426
EEC IV42617.14 Lucar type “octane
adjustment” connectors -
early models with ESC II
and EEC IV systems
A Red, blue and yellow connectors
B Coil securing screw (earthing point)