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5•2 Engine electrical systems
Ignition coil
Make . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Primary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Secondary resistance:
All except DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output voltage (open-circuit):
All except DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DOHC fuel-injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HT leads
Maximum resistance per lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Distributor
Make . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic advance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition timing (see text)
SOHC and 2.8 litre V6 engines:
Leaded fuel (97 octane):
Carburettor models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel-injection models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unleaded fuel (95 octane):
Carburettor models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel-injection models:
2.0 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4 & 2.9 litre V6 engines:
Models with catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Models without catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . .
* Standard setting for 97 octane leaded fuel.
Torque wrench settings
Alternator adjusting strap:
To steering pump bracket (OHC) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
To front cover (V6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Spark plugs:
All models except 2.8 litre V6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8 litre V6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air charge temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel rail temperature sensor (DOHC) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft speed/position sensor screw (DOHC) . . . . . . . . . . . . . . . . .
1 General information and
precautions
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.
Bosch, Femsa or Polmot
0.72 to 0.86 ohm
4.5 to 7.0 k ohms
4.5 to 8.6 k ohms
25 kV minimum
30 kV minimum
30 k ohms
Bosch or Motorcraft
Clockwise (viewed from above)
Controlled by module
Controlled by module
10° BTDC
12°BTDC
6°BTDC
8°BTDC
12°BTDC (no change)
15° BTDC
12° BTDC*
Nm
21 to 26
41 to 51
20 to 28
30 to 40
20 to 25
20 to 25
8 to 11
3 to 5
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
lbf ft
16 to 19
30 to 38
15 to 21
22 to 30
15 to 18
15 to 18
6 to 8
2 to 4
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