The ignition system is responsible for
igniting the fuel/air charge in each cylinder at
the correct moment. The components of the
system are the spark plugs, ignition coil,
distributor and connecting leads. Overall
control of the system is one of the functions of
the engine management module. Fuel-
injection models have a subsidiary ignition
module mounted on the distributor.
There are no contact breaker points in the
distributor. A square wave signal is generated
by the distributor electro-magnetically; this
signal is used by the engine management
module as a basis for switching the coil LT
current. Speed-related (centrifugal) advance is
also handled by the module. On carburettor
models, ignition timing is also advanced under
conditions of high inlet manifold vacuum.The engine management models are “black
boxes” which regulate both the fuel and the
ignition systems to obtain the best power,
economy and emission levels. The module
fitted to carburettor models is known as the
ESC II (Electronic Spark Control Mk II) module.
On fuel-injection models the more powerful
EEC IV (Electronic Engine Control Mk IV)
module is used.
Both types of module receive inputs from
sensors monitoring coolant temperature,
distributor rotor position and (on some
models) manifold vacuum. Outputs from the
module control ignition timing, inlet manifold
heating and (except on 1.8 litre models) idle
speed. The EEC IV module also has overall
control of the fuel-injection system, from
which it receives information.
Provision is made for the ignition timing to
be retarded to allow the use of low octane fuel
if necessary. On all except 1.8 litre models
there is also a facility for raising the idle speed.The EEC IV module contains self-test
circuitry which enables a technician with the
appropriate test equipment to diagnose faults
in a very short time. A Limited Operation
Strategy (LOS) means that the car is still
driveable, albeit at reduced power and
efficiency, in the event of a failure in the
module or its sensors.
Due to the complexity and expense of the
test equipment dedicated to the engine
management system, suspected faults should
be investigated by a Ford dealer, or other
competent specialist. This Chapter deals with
component removal and refitting, and with
some simple checks and adjustments.
On DOHC carburettor engines, the basic
operating principles of the ignition system are
as described above. A development of the
ESC II (Electronic Spark Control ll) system is
used to control the operation of the engine.
The ESC II module receives information from a
crankshaft speed/position sensor and an
1General information and
precautions
5•2Engine electrical systems
Ignition coil
Make . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bosch, Femsa or Polmot
Primary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.72 to 0.86 ohm
Secondary resistance:
All except DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.5 to 7.0 k ohms
DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.5 to 8.6 k ohms
Output voltage (open-circuit):
All except DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 kV minimum
DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 kV minimum
HT leads
Maximum resistance per lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 k ohms
Distributor
Make . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bosch or Motorcraft
Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Clockwise (viewed from above)
Automatic advance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Controlled by module
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Controlled by module
Ignition timing (see text)
SOHC and 2.8 litre V6 engines:
Leaded fuel (97 octane):
Carburettor models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10°BTDC
Fuel-injection models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12°BTDC
Unleaded fuel (95 octane):
Carburettor models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6°BTDC
Fuel-injection models:
2.0 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8°BTDC
2.8 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12°BTDC (no change)
2.4 & 2.9 litre V6 engines:
Models with catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15°BTDC
Models without catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . .12°BTDC*
* Standard setting for 97 octane leaded fuel.
Torque wrench settingsNmlbf ft
Alternator adjusting strap:
To steering pump bracket (OHC) . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2616 to 19
To front cover (V6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 to 5130 to 38
Spark plugs:
All models except 2.8 litre V6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2815 to 21
2.8 litre V6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 to 4022 to 30
Air charge temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Engine coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Fuel rail temperature sensor (DOHC) . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
Crankshaft speed/position sensor screw (DOHC) . . . . . . . . . . . . . . . . .3 to 52 to 4
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