1993 FORD SIERRA EXC II

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

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)

EEC IV modules
Ignition module
Models up to 1987
Note: When refitting, the rear face of the
module must be coated with heat sink
compound. Refer to a Ford dealer for advice if
necessary.
12The module is mounted on the distributor
body.
13Disconnect the distributor wiring plug by
depressing the locking tabs. Pull on the plug,
not the wiring.
14Remove the two securing screws from the
module, then slide the module downwards
and withdraw it (see illustration).
15Refitting is a reversal of removal, but the
rear face of the module must be coated with
heat sink compound. Do not force the module
into position, as damage to the electrical
contacts may result.
Models from 1987
16The module is mounted on the left-hand
side of the engine compartment (see
illustration).
17Disconnect the module wiring plug by
depressing the locking tabs. Pull on the plug,
not the wiring.
18Remove the two securing screws and
withdraw the module from the engine
compartment.
19Refitting is a reversal of removal, but
ensure that the underside of the module and
the corresponding area of the body panel are
clean.
1.6 and 1.8 litre (R6A type) CVH models
20The ignition module is located at the front
right-hand side of the engine compartment. 21Disconnect the battery negative lead.
22Release the securing lug, and pull the
wiring plug from the module. Pull on the plug,
not on the wiring (see illustration).
23Remove the two securing screws, and
withdraw the module from the body panel.
24Refitting is a reversal of removal.
2.0 litre DOHC fuel injection models
25The ignition module is located on the left-
hand side of the engine compartment,
beneath the coil (see illustration).
26Disconnect the battery negative lead.
27Remove the two securing screws, and
withdraw the coil/ignition module heat shield.
28Release the locking lug and disconnect
the ignition module wiring plug. Pull on the
plug, not on the wiring.
29Remove the two securing screws, and
withdraw the module from the body panel.
30Refitting is a reversal of removal, ensuring
that the underside of the module and the
corresponding area of the body panel are clean.
Engine management module
All models except 1.6 and 1.8 litre CVH
(R6A type) and 2.0 litre DOHC fuel injection
31The module is located inside the
passenger compartment behind the
passenger side facia.
32Unclip the trim panel from below the
glovebox on models up to 1987, or from
above the glovebox on models from 1987.
33Unclip the module retainer and withdraw
the module.
34The wiring plug is secured by a screw
which is integral with the plug. Disconnect the
wiring plug and remove the module.35Refitting is a reversal of removal, noting
that the wiring plug will only fit in one position.
1.6 and 1.8 litre (R6A type) CVH models
36The module is located in the passenger
compartment, behind the glovebox.
37Disconnect the battery negative lead.
38Open the glovebox, and carefully pull it
from its retaining clips.
39Unclip and withdraw the module from its
retaining bracket (see illustration).
40The wiring plug is secured by a screw
which is integral with the plug. Disconnect the
wiring plug, and withdraw the module.
41Refitting is a reversal of removal, noting
that the wiring plug will only fit in one position.
2.0 litre DOHC fuel injection models
42For models up to 1990 refer to the first 5
paragraphs of this sub Section.
43For models from 1990 refer to the
procedure given for 1.6 and 1.8 litre CVH (R6A
type) engines.
Note: Procedures for removal and refitting of
the ignition system components and
electronic module are given elsewhere in the
relevant Sections of this Chapter.
1Disconnect the battery negative lead.
Engine coolant temperature
sensor
All models except 2.0 litre DOHC
2The sensor is located in the underside of
the inlet manifold.
19ESC II system components -
removal and refitting
5•20Engine electrical systems
18.14 EEC IV ignition module securing
screws (arrowed) - models up to 198718.22 Disconnecting the ignition module
wiring plug
19.4 Disconnect engine temperature
sensor wiring plug - ESC II system18.39 Engine management module
withdrawn from its mounting bracket18.25 Ignition module location (arrowed)
18.16 EEC IV ignition module - models
from 1987