octane FORD MONDEO 1993 Service Repair Manual

3Using an ohmmeter, measure the
resistance of the coil’s primary windings,
connecting the meter between the coil’s
terminal pins as follows. Measure first from
one outer pin to the centre pin, then from the
other outer pin to the centre. Compare your
readings with the coil primary resistance listed
in the Specifications Section at the beginning
of this Chapter.
4Disconnect the spark plug (HT) leads - note
their connections or label them carefully, as
described in Chapter 1. Use the meter to
check that there is continuity (ie, a resistance
corresponding to that of the coil secondary
winding) between each pair of (HT) lead
terminals; Nos 1 and 4 terminals are
connected by their secondary winding, as are
Nos 2 and 3. Now switch to the highest
resistance scale, and check that there is no
continuity between either pair of terminals and
the other - ie, there should be infinite
resistance between terminals 1 and 2, or 4
and 3 - and between any terminal and earth.
5If either of the above tests yield resistance
values outside the specified amount, or
results other than those described, renew the
coil. Any further testing should be left to a
dealer service department or other qualified
repair facility.
Removal and refitting
6Disconnect the battery negative (earth) lead
- see Section 1.
7Remove the air mass meter and resonator -
refer to Chapter 4.
8Unplug the electrical connector from each
side of the coil, then disconnect the spark
plug (HT) leads - note their connections or
label them carefully, as described in Chapter
1.
9Undo the two screws securing the EGR
pipe to the coil bracket, then remove the coil
mounting (Torx-type) screws. Withdraw the
coil assembly from the cylinder head (see
illustration).
10The suppressor can be unbolted from the
mounting bracket, if required; note that the
coil and bracket are only available as a single
unit.
11Refitting is the reverse of the removalprocedure. Ensure that the spark plug (HT)
leads are correctly reconnected, and tighten
the coil screws securely.
Note:See Chapter 6 for component location
illustrations.
1Disconnect the battery negative (earth) lead
- see Section 1.
2If better access is required, remove the
resonator (see Chapter 4).
3Unplug the electrical connector from the
module (see illustration).
4Remove the retaining screws, and detach
the module from the bulkhead mounting
bracket.
5Refitting is the reverse of the removal
procedure.
As noted in Section 4, the ignition timing is
controlled entirely by the ECU (acting with the
ignition module, on models with automatic
transmission), and cannot be adjusted. The
value quoted in the Specifications Section of
this Chapter is for reference only, and mayvary significantly if “checked” by simply
connecting a timing light to the system and
running the engine at idle speed.
Not only can the ignition timing not be
adjusted, it cannot be checked either, except
with the use of special diagnostic equipment
(see Chapter 6) - this makes it a task for a
Ford dealer service department.
Owners who are taking their vehicles
abroad should note that the ignition system is
set for the engine to use petrol of 95 RON
octane rating by fitting a “plug-in bridge” to
the service connector on the engine
compartment bulkhead (see illustration).
Removing the “plug-in bridge” retards the
ignition timing - by an unspecified value - to
allow the engine to run on 91 RON fuel. This
grade of fuel is the “Regular” or “Normal”
widely used abroad, but not at present
available in the UK. If you are taking the
vehicle abroad, seek the advice of a Ford
dealer (or of one of the motoring
organisations). This will ensure that you are
familiar with the grades of fuel you are likely to
find (and the sometimes confusing names for
those grades), and that the vehicle is set
correctly at all times for the fuel used. Note:
The octane ratings mentioned above are both,
of course, for unleadedpetrol. Do not use
leaded petrol at any time in a vehicle equipped
with a catalytic converter.
Checking
1See Section 4 of Chapter 6.
Removal and refitting
2Disconnect the battery negative (earth) lead
- see Section 1.
3Raise the front of the vehicle, and support it
securely on axle stands.
Warning: Do not place any part of
your body under a vehicle when
it’s supported only by a jack!
4Unplug the sensor’s electrical connector
(see illustration).
9 Crankshaft speed/position
sensor-
checking, removal and refitting
8 Ignition timing - checking
7 Ignition module (automatic
transmission models only) -
removal and refitting
5•4 Engine electrical systems
6.9 Unplug coil electrical connector (A),
suppressor connector (B), and spark
plug/HT leads (C), remove screws (D), then
undo Torx-type screws (E) to release
ignition coil assembly7.3 Separate ignition module is fitted to
automatic transmission models only - note
electrical connector (A) and retaining
screws (B)
8.3 Service connector (A) mounted on
engine compartment bulkhead is fitted with
“plug-in bridge” (B) to set engine to use
(unleaded) petrol of 95 RON octane rating9.4 Location of crankshaft speed/position
sensor - connector arrowed - in front of
cylinder block/crankcase
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Emissions control systems 6•3
6
2.1B Location of principal fuel injection, ignition and
emissions control system components 2.1A Engine management system, showing fuel injection,
ignition and emissions control sub-systems
1 ECU (Electronic Control Unit)
2 Fuel pump/fuel gauge sender
unit
3 Fuel pump relay
4 Fuel filter
5 Idle speed control valve
6 Air mass meter
7 Air cleaner assembly
8 Fuel pressure regulator
9 Fuel rail
10 Throttle potentiometer
11 Intake air temperature sensor
12 Fuel injector
13 Camshaft position sensor
14 Charcoal canister
15 Charcoal canister-purge
solenoid valve
16 Ignition coil
17 Battery
18 Ignition module - only
separate (from ECU) on
vehicles with automatic
transmission
19 Coolant temperature sensor
20 Oxygen sensor
21 Crankshaft speed/position
sensor
22 Power supply relay
23 Power steering pressure
switch24 Air conditioning compressor
clutch solenoid
25 Service connector - for octane
adjustment
26 Self-test connector - for Ford
STAR tester diagnostic
equipment
27 Diagnosis connector - for Ford
diagnostic equipment FDS
2000
28 Ignition switch
29 Fuel cut-off switch
30 Exhaust Gas Recirculation
(EGR) solenoid valve
31 Exhaust Gas Recirculation
(EGR) valve
32 Exhaust Gas Recirculation
(EGR) exhaust gas pressure
differential sensor
33 Exhaust Gas Recirculation
(EGR) pressure differential
measuring point
34 To inlet manifold
35 Pulse-air filter housing
36 Pulse-air solenoid valve
37 Air conditioning/radiator
electric cooling fan control
38 Automatic transmission
control system - where
applicable1 ECU (Electronic Control Unit)
2 Self-test, diagnosis and service connectors
(left to right)
3 Bulkhead component mounting bracket - manual
transmission - showing from left to right, (EGR) solenoid
valve, pulse-air solenoid valve and (EGR) exhaust gas
pressure differential sensor
4 Bulkhead component mounting bracket - automatic
transmission - showing from left to right, (EGR) solenoid
valve, pulse-air solenoid valve and (EGR) exhaust gas
pressure differential sensor, with separate ignition module
above
5 Throttle housing, including potentiometer
6 Idle speed control valve
7 Intake air temperature sensor
8 Air mass meter
9 Exhaust Gas Recirculation (EGR) valve
10 Coolant temperature sensor
11 Crankshaft speed/position sensor
12 Pulse-air filter housing
13 Oxygen sensor
14 Ignition coil and spark plug (HT) leads
15 Camshaft position sensor
16 Fuel injector(s)
17 Power steering pressure switch
18 Air cleaner assembly
19 Air intake tube and resonators - under left-hand front wing
20 Resonator
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back again, as an assistant depresses the
accelerator pedal. If the valve shows any sign
of stiffness, sticking or otherwise-inhibited
movement (and the accelerator cable is
known from the previous check to be in good
condition), spray the throttle linkage with
penetrating lubricant, allow time for it to work,
and repeat the check; if no improvement is
obtained, the complete throttle housing must
be renewed (Chapter 4).
15Unclip the air cleaner cover, and check
that the air filter element and the crankcase
ventilation system filter are not clogged or
soaked. (A clogged air filter will obstruct the
intake air flow, causing a noticeable effect on
engine performance; a clogged crankcase
ventilation system filter will inhibit crankcase
“breathing”). Renew or clean the filter(s) as
appropriate; refer to the relevant Sections of
Chapter 1 for further information, if required.
Before refitting the air cleaner cover, check
that the air intake (located under the front left-
hand wing, opening behind the direction
indicator/headlight assembly) is clear. It
should be possible to blow through the intake,
or to probe it (carefully) as far as the rear of
the direction indicator light.
16Start the engine and allow it to idle.
Note:Working in the engine compartment
while the engine is running requires great care
if the risk of personal injury is to be avoided;
among the dangers are burns from contact
with hot components, or contact with moving
components such as the radiator cooling fan
or the auxiliary drivebelt. Refer to “Safety
first!” at the front of this manual before
starting, and ensure that your hands, and long
hair or loose clothing, are kept well clear of hot
or moving components at all times.
17Working from the air intake junction at the
inner wing panel, via the air cleaner assembly
and air mass meter, to the resonator, plenum
chamber, throttle housing and inlet manifold
(and including the various vacuum hoses and
pipes connected to these), check for air leaks.
Usually, these will be revealed by sucking or
hissing noises, but minor leaks may be traced
by spraying a solution of soapy water on to
the suspect joint; if a leak exists, it will be
shown by the change in engine note and the
accompanying air bubbles (or sucking-in of
the liquid, depending on the pressure
difference at that point). If a leak is found at
any point, tighten the fastening clamp and/or
renew the faulty components, as applicable.
18Similarly, work from the cylinder head, via
the manifold (and not forgetting the related
EGR and pulse-air system components) to the
tailpipe, to check that the exhaust system is
free from leaks. The simplest way of doing
this, if the vehicle can be raised and
supported safely and with complete security
while the check is made, is to temporarily
block the tailpipe while listening for the sound
of escaping exhaust gases; any leak should
be evident. If a leak is found at any point,
tighten the fastening clamp bolts and/or nuts,
renew the gasket, and/or renew the faultysection of the system, as necessary, to seal
the leak.
19It is possible to make a further check of
the electrical connections by wiggling each
electrical connector of the system in turn as
the engine is idling; a faulty connector will be
immediately evident from the engine’s
response as contact is broken and remade. A
faulty connector should be renewed to ensure
the future reliability of the system; note that
this may mean the renewal of that entire
section of the loom - see your local Ford
dealer for details.
20Switch off the engine. If the fault is not yet
identified, the next step is to check the
ignition voltages, using an engine analyser
with an oscilloscope - without such
equipment, the only tests possible are to
remove and check each spark plug in turn, to
check the spark plug (HT) lead connections
and resistances, and to check the
connections and resistances of the ignition
coil. Refer to the relevant Sections of
Chapters 1 and 5.
21The final step in these preliminary checks
would be to use an exhaust gas analyser to
measure the CO level at the exhaust tailpipe.This check cannot be made without special
test equipment - see your local Ford dealer for
details.
Fault code read-out
22As noted in the general comments at the
beginning of this Section, the preliminary
checks outlined above should eliminate the
majority of faults from the engine
management system. If the fault is not yet
identified, the next step is to connect a fault
code reader to the ECU, so that its self-
diagnosis facility can be used to identify the
faulty part of the system; further tests can
then be made to identify the exact cause of
the fault.
23In their basic form, fault code readers are
simply hand-held electronic devices, which
take data stored within an ECU’s memory and
display it when required as two- or three-digit
fault codes. The more sophisticated versions
now available can also control sensors and
actuators, to provide more effective testing;
some can store information, so that a road
test can be carried out, and any faults
encountered during the test can be displayed
afterwards.
6•6 Emissions control systems
3.26 Location and terminal identification of engine management system self-test,
diagnosis and service connectors
1 Power steering fluid reservoir
2 Diagnosis connector - for Ford diagnostic equipment FDS 2000
3 Self-test connector - for fault code read-out - pin 17 is output terminal, pin 48 is input
terminal, pin 40/60 is earth
4 Service connector - for octane adjustment
5 Plug-in bridge - to suit 95 RON fuel
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