Ford Orion. Manual - part 37

Refitting

4 Reconnect the wiring connector to the
switch, ensuring that it is felt to snap securely
into position.
5 Relocate the switch, and refit the screws to
secure it.
6 Reset the switch by pushing the top button
down, then refit the side cowl trim panel.
7 Reconnect the battery and restart the
engine to ensure that the switch has reset.

12 Fuel injection system/engine

management system (1.3 and
1.4 litre CFi) - general information

Fuel is supplied from the fuel tank by an

integral electric fuel pump (and combined fuel
gauge sender unit). The fuel is passed through
an in-line filter within the engine compartment,
then to the fuel injection unit. The fuel is
maintained at the required operating pressure
by a pressure regulator unit.

The CFi unit itself is a relatively simple

device when compared with a conventional
carburettor. Fuel is injected by a single
solenoid valve (fuel injector) which is mounted
centrally on top of the unit. It is this feature
which gives the system CFi (or Central Fuel
Injection) its name (see illustration).

The injector is energised by an electrical

signal sent from the engine management
ECU. When energised, the injector pintle is
lifted from its seat, and atomised fuel is
delivered into the inlet manifold under
pressure. The electrical signals take two forms
of current - a high current to open the injector,
and a low current to hold it open for the
duration required. At idle speed, the injector is
pulsed at every other inlet stroke, rather than
with every stroke as during normal operation.

The air-to-fuel mixture ratio is regulated by

the engine management ECU, based on
inputs from the various engine sensors, the
operation of which is described in greater
detail in Chapter 6. No adjustments to the fuel
mixture are possible.

The throttle plate control motor (mounted on

the side of the CFi unit) regulates the idle speed
by reacting to the signals sent by the ECU. The
signals are calculated by the values and
information provided from the engine sensors.
When the throttle position sensor indicates that
the throttle is closed, the ECU enters the idle
speed mode or dashpot mode (according to
engine speed). The ECU maintains the idle
speed at a constant value, making minor
adjustments as necessary for different loads
and conditions. The base idle speed can only
be adjusted by a dealer or fuel injection
specialist with the necessary equipment to link
up to the engine management ECU.

To prevent the engine from running on (or

dieselling) when it is switched off, the ECU
sends a signal to the throttle plate control
motor, to fully close the throttle plate and
return it to its preset position ready for

restarting. When the ignition is switched on to
restart the engine, the motor repositions the
throttle plate to the position required
according to the prevailing conditions.

13 Fuel injection/engine management

systems (1.6 and 1.8 litre EFi 
and SEFi) - general  information

EFi system

Fuel is supplied under pressure from the

fuel pump to the fuel distributor rail mounted
on top of the inlet manifold (see illustration).
The fuel rail acts as a pressurised fuel
reservoir for the fuel injectors. The electro-
mechanical injectors have only “on” or “off”
positions, the volume of fuel being injected to

meet the engine operating conditions being
determined by the length of time that the
injectors are opened. The volume of fuel
required for one power stroke is determined
by the engine management ECU, and is
divided by two equal amounts. The first half of
the required volume is injected into the static
air ahead of the inlet valve one complete
engine revolution before the inlet valve is due
to open. After one further revolution, the inlet
valve opens and the required fuel volume is
injected into the air flow being drawn into the
cylinder. The fuel will therefore be consistently
injected to two inlet valves simultaneously at a
particular crankshaft position.

The volume of air drawn into the engine is

governed by the air filter unit and other
variable operating factors. These variables are
assessed by the engine management ECU

Fuel and exhaust systems – fuel-injected engines  4B•7

12.2  Exploded view of the CFi unit fitted to 1.3 and 1.4 litre engines

4B

1  Fuel injection unit
2  Fuel pressure regulator 

unit

3  Fuel feed connector
4  Inlet air temperature sensor
5  Throttle plate control motor

6  Throttle position sensor
7  Fuel injector wiring

and the corresponding signals are produced
to actuate the injectors accordingly.

The engine base idle speed can be adjusted

(if required), by turning the adjuster screw
(covered by a tamperproof cap) in the throttle
housing. Provision for adjusting the fuel
mixture is made by the mixture screw in the
potentiometer unit mounted on the bulkhead.

Further information on the engine

management system and its various sensors
and sub-systems will be found in Chapter 6.

SEFi system

The electric fuel pump located inside the

fuel tank supplies fuel under pressure to the
fuel rail, which distributes fuel evenly to all
injectors. A pressure regulator controls the
system pressure in relation to inlet tract
depression. From the fuel rail, fuel is injected
into the inlet ports, just above the inlet valves,
by four fuel injectors. The system also
includes features such as the flushing of fresh
(ie, cold) fuel around each injector on start-up,
thus improving hot starts.

The amount of fuel supplied by the injectors

is precisely controlled by the engine
management ECU. The ECU uses the signals
derived from the engine speed/crankshaft
position sensor and the camshaft position
sensor, to trigger each injector separately in
cylinder firing order (sequential injection), with
benefits in terms of better fuel economy and
lower exhaust emissions.

The air inlet side of the system consists of

an air cleaner housing, an air mass meter, an
inlet hose and duct, and a throttle housing.
The air mass meter is an information-
gathering device for the ECU; it uses a “hot-
wire” system to send the ECU a constantly-
varying (analogue) voltage signal
corresponding to the volume of air passing
into the engine. Another sensor in the air mass
meter measures inlet air temperature. The
ECU uses these signals to calculate the mass
of air entering the engine.

The throttle valve inside the throttle housing

is controlled by the driver, through the
accelerator pedal. As the valve opens, the
amount of air that can pass through the
system increases. The throttle potentiometer
opens further, the air mass meter’s signal
alters, and the ECU opens each injector for a
longer duration, to increase the amount of fuel
delivered to the inlet ports.

Both the idle speed and mixture are under

the control of the ECU, and cannot be
adjusted. Not only can they not be adjusted,
they cannot even be checked, except with the
use of special diagnostic equipment, which
makes it a task for a Ford dealer service
department. Do not attempt to “adjust” these
settings in any way without such equipment.

If the idle speed and mixture are thought to

be incorrect, take the vehicle to a Ford dealer
for the complete system to be tested.

Further information on the engine

management system and its various sensors
and sub-systems will be found in Chapter 6.

14 Fuel injection system/engine

management system -
checking

3

Warning: Petrol is extremely
flammable, so extra precautions
must be taken when working on
any part of the fuel system. Do not

smoke, or allow open flames or bare light
bulbs, in or near the work area. Don’t work
in a garage if a natural-gas appliance with a
pilot light is present. While performing any
work on the fuel system, wear safety
glasses, and have a dry chemical (Class B)
fire extinguisher on hand. If you spill any
fuel on your skin, rinse it off immediately
with soap and water.

Note: This is a basic check of the fuel delivery
and air induction sub-systems of the engine
management system, to be carried out in
conjunction with the operational check of the
fuel pump (see Section 7), and as part of the
initial system checks of the complete engine
management system (see Section 3 of
Chapter 6).
1 Check the earth wire connections for
tightness. Check all wiring and electrical
connectors that are related to the system.
Loose electrical connectors and poor earths
can cause many problems that resemble
more serious malfunctions.
2 Check to see that the battery is fully-
charged. The ECU and sensors depend on an
accurate supply voltage to properly meter the
fuel.
3 Check the air cleaner filter element - a dirty
or partially-blocked filter will severely impede
performance and economy (see Chapter 1).

4 If a blown fuse is found, renew it and see if
it blows again. If it does, search for a short-
circuited wire in the harness related to the
system (see Chapter 6).
5 Check the CFI unit/throttle housing and
inlet manifold joints for leaks, which will result
in an excessively-lean mixture (see
illustration). Also check the condition of the
vacuum hoses connected to the inlet
manifold.
6 On EFi and SEFi systems, remove the air
inlet duct from the throttle housing. Check the
throttle valve for dirt, carbon or other residue
build-up. If it’s dirty, seek the advice of a Ford
dealer - since the electronic control system is
designed to compensate for factors such as
the build-up of dirt in the throttle housing, it
may well be best to leave it dirty, unless the
deposits are extensive. Note: A warning label
on the housing states specifically that the
housing bore and the throttle valve have a
special coating, and must not be cleaned
using carburettor cleaner, as this may damage
it.

4B•8 Fuel and exhaust systems – fuel-injected engines

14.5  Check the points indicated on the CFi

unit for induction leaks

1  Throttle housing
2  Upper inlet manifold section
3  Wiring loom connector
4  Inlet air temperature sensor
5  Wiring harness ducting

6  Fuel distributor rail
7  Lower section of inlet 

manifold

8  Cylinder head

9  Fuel injector

10  Fuel pressure regulator
11  Vacuum hose
12  Air inlet duct

13.1  General view of the fuel injection system arrangement on the 1.6 litre EFi model

7 On EFi and SEFi systems, with the engine
running, place a screwdriver or a stethoscope
against each injector, one at a time. Listen
through the screwdriver handle or
stethoscope for a clicking sound, indicating
operation.
8 If an injector doesn’t appear to be
operating, turn off the engine and carefully
check the wiring plug connection on the
injector, and the wiring itself. If all appears
okay, have the injector tested by a specialist.
9 A rough idle, diminished performance
and/or increased fuel consumption could also
be caused by a clogged or fouled fuel
injector(s). Fuel additives that can sometimes
clean fouled injectors are available at car
accessory shops.
10 The remainder of the system checks
should be left to a dealer service department
or other qualified repair specialist, as there is
a chance that the ECU may be damaged if
tests are not performed properly.

15 Fuel injection system

components (1.3 and 1.4 litre
CFi) - checking and renewal

3

Warning: The fuel system
pressure must be released before
any part of the system is
disturbed - see Section 2. Petrol

is extremely flammable, so take extra
precautions when you work on any part of

the fuel system. Don’t smoke, or allow
open flames or bare light bulbs, in or near
the work area. Don’t work in a garage
where a natural-gas appliance (such as a
water heater or clothes dryer) with a pilot
light is present. If you spill any fuel on your
skin, rinse it off immediately with soap and
water. When you perform any kind of work
on the fuel system, wear safety glasses,
and have a Class B type fire extinguisher
on hand.

Fuel injector

Check

1 Refer to Section 4 and remove the air
cleaner.
2 Disconnect the multi-plug connector from
the E-DIS ignition coil (to prevent the engine
from starting).
3 Get an assistant to turn the engine over on
the starter motor, while you look down
through the top of the CFi unit and check that
fuel is seen to be delivered into the central
venturi.
4 If the fuel supply is seen to be acceptable
but the engine will not start, refer to the
ignition and engine management system test
procedures contained in Chapters 5 and 6.

Renewal

5 Relieve the residual pressure in the fuel
system (see Section 2), and equalise tank
pressure by removing the fuel filler cap. 

Warning: This procedure will
merely relieve the increased
pressure necessary for the
engine to run - remember that

fuel will still be present in the system
components, and take precautions
accordingly before disconnecting any of
them.
6 Disconnect the battery negative (earth) lead
(refer to Chapter 5, Section 1).
7 Refer to Section 4 and remove the air
cleaner.
8 Release the injector feed wiring multi-plug,
and detach it from the injector (pulling on the
plug - not the wire) (see illustration).
9 Bend over the locking tabs retaining the
injector screws, then undo and remove the
screws. Withdraw the injector retaining collar,
then carefully withdraw the injector from the
CFi unit (noting its orientation) followed by its
seal (see illustrations).
10 Refit in the reverse order of removal.
Always use new seals in the CFi unit and the
retaining collar, and lightly lubricate them with
clean engine oil prior to assembly. Take care
not to damage the seals as they are fitted and
as the injector is fitted, check that the location
peg engages correctly (see illustration).

Fuel pressure regulator

Check

11 Refer to the fuel pump/fuel pressure
check procedure (Section 7).

Fuel and exhaust systems – fuel-injected engines  4B•9

15.9B  . . . and remove the injector

retaining collar

15.9A  Remove the injector retaining collar

bolt and locktab . . .

15.8  Disconnect the multi-plug from the

injector

15.9E  Withdrawing the seal from the

injector retaining collar

15.9D  Injector seal location (arrowed) in

the CFi unit

15.9C  Withdraw the injector from the CFi

unit

4B

Renewal

12 Refer to paragraphs 20 to 28 in this
Section and remove the CFi unit from the
vehicle.
13 Unscrew and remove the four regulator
retaining screws, and remove the regulator
(see illustration). As they are removed, note
the fitting positions and the orientation of the
components.  Do not (unless absolutely
necessary) attempt to prise out the plug or
adjust the screw in the centre of the housing
(if no plug fitted), as this will alter the system
pressure.
14 Examine the components, and renew any
that are defective or suspect.
15 To refit, position the regulator on its side,
then insert the small spring, the valve,
diaphragm (ensuring that it seats correctly),
large spring, cup and then the regulator cover.
Insert and tighten the retaining screws, but
take care not overtighten them, or the cover
will be distorted.
16 Carefully place the ball into position on
the spring cup, and ensure that it seats
correctly.
17 If removed, fit the central Allen type
adjuster screw, hand-tighten it and then
unscrew it (from the hand-tight position) three
full turns to make a provisional adjustment.
18 Refit the CFi unit in accordance with
paragraphs 29 to 31 in this Section, but note
that further checks for fuel leaks must be
made with the engine running. The fuel
system pressure must be checked by a Ford

dealer or other suitable specialist at the
earliest opportunity.

CFi unit

Check

19 Refer to paragraphs 1 to 4 in this Section.

Renewal

20 Relieve the residual pressure in the fuel
system (see Section 2), and equalise tank
pressure by removing the fuel filler cap. 

Warning: This procedure will
merely relieve the increased
pressure necessary for the engine
to run - remember that fuel will

still be present in the system components,
and take precautions accordingly before
disconnecting any of them.
21 Disconnect the battery negative (earth)
lead (refer to Chapter 5, Section 1).
22 Refer to Section 4 and remove the air
cleaner.
23 Position a suitable drain tray under the
coolant hose connections to the CFi unit, then
detach the hoses from the unit. Plug or clamp
the hoses to prevent further coolant spillage
whilst the hoses are detached.
24 Disconnect the fuel return pipe from the
CFi unit.
25 Refer to Section 5 and disconnect the
accelerator cable from the CFi unit.
26 Disconnect the inlet air temperature
sensor, throttle plate control motor and
throttle position sensor wiring multi-plug
connectors.

27 Disconnect the vacuum hose from the CFi
unit.
28 Unscrew and remove the four retaining
screws, and remove the CFi unit from the inlet
manifold  (see illustration). Remove the
gasket.
29 Clean the CFi unit and the inlet manifold
mating faces.
30 Refit in the reverse order of removal.
Tighten the retaining bolts to the specified
torque wrench setting. Check and top-up the
cooling system as required (Chapter 1).
31 When the CFi unit is refitted, turn the
ignition on and off at least five times to
pressurise the system, and check for leaks.

Throttle plate control motor

Check

32 Open the bonnet and watch the throttle
plate control motor, while an assistant starts
the engine, then turns the ignition key off. The
motor should be seen to retract and then
extend so that it is ready for the next engine
restart. The throttle plate control motor can be
individually checked for operation by
connecting a 12-volt supply direct to the
motor multi-plug (see illustration).
Depending on the polarity, the motor should
extend or retract. Changing the polarity
should reverse the action.

Renewal

33 Disconnect the battery negative (earth)
lead (refer to Chapter 5, Section 1).

4B•10 Fuel and exhaust systems – fuel-injected engines

15.35B  Releasing the throttle position

sensor multi-plug from the retaining clip

15.35A  Disconnecting the throttle plate

control motor multi-plug

15.32  Throttle plate control motor check.

Inset shows test connections to multi-plug

15.28  CFi unit retaining screws (arrowed)

15.13  Fuel pressure regulator and

retaining screws (arrowed) - shown in situ

15.10  Showing position of the injector

location peg (arrowed)