Electric system FIAT MAREA 2000 1.G Owner's Manual

Fuel feed system
Engine Marea- Marea Weekend © ™
2000 range @
10.
The control unit autodiagnostic system checks the signals coming from the sensors and compares them
with the figures allowed:
- signalling faults during starting
- warning light on for 4 seconds indicates test stage
- warning light off after 4 seconds indicates no fault with components that could alter the pollution con­
trol standard figures
- warning light on after 4 seconds indicates fault.
- signalling faults during operation
- warning light on indicates fault
- warning light off indicates no fault with components that could alter the pollution control standard fig­
ures.
- recovery
- from time to time, the control unit defines the type of recovery according to the components which are
faulty
- the recovery parameters are managed by components which are not faulty.
Control of cylinder balancing during idling
According to the signals coming from the sensors, the injection control unit controls the idle speed torque,
altering the injector operating times.
Control of irregular operation
Depending on the signals coming from the sensors, the injection control unit corrects the amount of fuel
to be injected in order to improve driveability and reduce jerking whilst driving.
The correction is achieved through the fuel pressure regulator and by varying the injector operating times.
Control of electrical balance
According to the battery voltage, the injection control unit alters the idle speed, to guarantee a sufficient
current supply from the alternator in situations where the consumers are absorbing a great deal of power.
The variation in the idle speed is achived by regulating the fuel pressure and altering the injector operat­
ing times.
VGT variable geometry turbocharger control (1910 JTD 110 CV)
The injection control unit processes the signal coming from the supercharging sensor, at the various en­
gine operating speeds, and determines the quantity of fuel to be injected, acting on the fuel pressure
regulator and the injector opening times.
In addition, through the solenoid valve, the control unit regulates the geometry of the turbine in order to
ensure optimum performance in all operating conditions.
Turbocharger waste gate valve control (1910 JTD 100 CV)
At the various engine operating speeds, the injection control unit processes the signal coming from the
supercharging sensor and determines the amount of fuel to inject, acting on the fuel pressure regulator
and the injector opening times.
In addition, the control unit controls the opening of the turbocharger waste gate valve, via the solenoid
valve, in order to ensure excellent performance in all operating conditions.
Control of throttle closing when engine is switched off
When the engine is switched off (ignition key in OFF position) the injection control unit closes the throt­
tle valve located on the air intake duct via the special solenoid valve.
This action makes it possible to limit the tiresome shuddering of the engine whilst it is switching off.
6 .i. V!-01-.Cancelftand replaces Print n° 506.763/25

Marea- Marea Weekend 9 ™
2000 range ©
Engine
Fuel feed system
10.
DIAGRAM SHOWING INFORMATION FLOW BETWEN THE INJECTION CONTROL UNIT AND
SENSORS/ACTUATORS
1. Auxiliary fuel pump
2. Variable geometry turbocharger control sole­
noid
3. Climate control compressor
4. Electric EGR valve
5. Rev counter
6. Engine radiator fan
7. Glow plug preheating control unit
8. Potentiometer on accelerator pedal
9. Brake and clutch pedal switches
10. Fuel pressure sensor
11. Intake air flow and temperature sensor (de-
bimeter)
12. Coolant temperature sensor
13. Fuel temperature sensor
14. Pressure relief sensor
15. Timing sensor
16. Rpm sensor
17. Vehicle speed signal
18. Battery
19. Four stage pressure switch
20. Fiat CODE control unit
21. Diagnostic socket
22. Fuel pressure regulator
23. Injectors
24. Throttle valve control solenoid
25. Glow plug preheating warning light
26. Injection system failure warning light
Copyright by Fiat Auto 1

Engine
Fuel feed system
10.
4F012XJ03
Marea- Matea Weekend 9 ™
2000 range (Q)
RPM SENSOR
The rpm sensor is fitted to the engine crank-
case and faces the phonic wheel on the
crankshaft.
The sensor is inductive type, i.e. it works by
varying a magnetic field generated when the
phonic wheel teeth (60-2 teeth) pass in front
of the sensor element.
The injection control unit uses the rpm sensor
signal to determine crankshaft speed and an­
gular position.
Operation
The changeover from full to empty due to the
presence or absence of teeth sets up a mag­
netic flux change sufficient to generate an in­
duced alternating voltage proportional to the
number of teeth on the phonic wheel.
The peak sensor output voltage value, all
things being equal, depends on the distance
between the sensor and the tooth (gap).
1. Steel bush
2. Permanent magnet
3. Sensor case
4. Winding
5. Core
6. Phonic wheel
7. Electrical connection
To obtain the correct signal, the specified gap
between phonic wheel and sensor should be
between 0.8 and 1.5 mm
This distance is not adjustable. When the gap
is not as specified, check the condition of the
sensor and phonic wheel.
Winding resistance
860 Ohm ±110% at 20 °C
1. Maximum magnetic flux
2. Minimum magnetic flux
3. Induced alternate voltage
12 Publication no, 506.763/24

Engine
Fuel feed system
10.
1. Pressure rod
2. Pin
3. Nozzle
4. Coil
5. Pilot valve
6. Ball plunger
7. Control area
8. Supply volume
9. Control volume
10. Fuel outlet connector (low pressure)
11. Control port
12. Supply port
13. Electrical connection
14. Fuel input connector (high pressure)
15. Spring
Marea- Marea Weekend 9 ™
2000 range (Q)
INJECTORS
The injectors are fitted to the cylinder head
and are electromagnetic in type. They are
controlled directly by the injection control
unit.
The injectors come with a high-pressure sup­
ply port and a recirculation pipe at environ­
mental pressure; The supply port is connected
to a delivery manifold (rail) with pipes de­
signed to withstand the high service pressures.
The injector can be divided into two parts:
- Actuator/spray made up of a pressure rod
(1), pin (2) and nozzle (3);
- control solenoid made up of coil (4) and
pilot valve (5).
Operation
Injector operation may be divided into three
stages:
1. rest position
Coil (4) is deactivated and plunger (6) is in
closed position to prevent fuel entering the
cylinder: Fc > Fa where Fc is the force gener­
ated by pressure acting on the control area (7)
of pressure rod (1) and Fa is the force due to
the pressure acting on supply volume (8).
2. Start of injection
Coil (4) is excited and causes plunger (6) to
rise. Fuel flows from control volume (9) to
the return manfold to bring about a pressure
drop in control area (7). Simultanteously, line
pressure through supply port (12) exerceses a
force Fa > Fc on supply volume (8) to cause
pin (2) to rise and thus allow fuel into the
cylinders.
3. end of injection
Coil (4) is deactivated and causes plunger (6)
to return to closed position. The resulting bal­
ance of forces makes pin (2) return to rest po­
sition and injection therefore ends.
14 Publication no. 506.763/24

Marea- Marea Weekend 9™
2000 range (§)
4F015XJ03
Engine
Fuel feed system
ijo.
ENGINE COOLANT TEMPERATURE
SENSOR
The sensor is fitted to the thermostat and
measures the temperature of the engine cool­
ant by means of an NTC thermistor with a
negative resistance coefficient.
Because the sensor is made using semicon­
ductor technology, the resistance falls if sen­
sor element temperature rises with increasing
coolant temperature.
Because resistance does not change in linear
manner, it is higher at low temperatures than
at high temperatures for the same temperature
increase.
1. NTC resistance
2. Sensor case
3. Electrical connector
FUEL TEMPERATURE
SENSOR
The sensor is fitted on the return manifold and
measures fuel temperature by means of an
NTC thermistor with a negative resistance co­
efficient.
Refer to the previous description of the cool­
ant temperature sensor for sensor operation.
FUEL PRESSURE SENSOR
The sensor is fitted in the middle of the fuel
delivery manifold (rail) and is responsible for
providing a return signal (feedback) to the
control unit in order to:
- adjust injection pressure;
- regulator injection duration.
Copyright by Fiat Auto 15

Engine
Fuel feed system
JTD Marea-Marea Weekend ©
2000 range ©
10.
iH
ft
B I 0 ] I D
[ 0 0 1 1
D
0 1 GLOW PLUG PREHEATING CONTROL
UNIT
The glow plugs are controlled by means of a
preheating control unit under the direct con­
trol of the injection control unit.
The preheating control unit contains a smart
relay that sends a return response (feedback)
to the injection control unit, which is thus in­
formed of faults in the preheating control unit
or glow plug short-circuits to earth.
The figure shows the connectors on the base
of the preheating control unit and the pin-out
1. Earth
2. Injection control unit (pin 22)
3. Power supply from main injection relay
4. Not connected
5. Injection control unit (pin 62)
8. Positive from battery (+30)
G. Glow plugs (only four outputs are used)
ACCELERATOR
PEDAL POTENTIOMETER
Accelerator pedal position is converted to an
electrical voltage signal and send to the injec­
tion control unit by a potentiometer connected
to the accelerator pedal.
Accelerator pedal position is processed to­
gether with rpm information to provide injec­
tion times and pressure.
The sensor consists of a case (1) secured to
the pedal by a flange, which contains an axi-
ally-positioned shaft (2) connected to two
potentiometers (3): main and safety potenti­
ometers.
A coil spring on the shaft ensures the correct
resistance to pressure while a second spring
ensures return upon release.
16 Publication no. 506.763/24

Marea-Marea Weekend 9 -™ Engine
2000 range (j§) Fuel feed system
10.
I I TEST
4F017XJ01
A switch (1) on the brake pedal con­
trols the car brake lights; the same
switch sends a signal to pin 59 of the
injection control unit
The control unit uses the "brake pedal
depressed" signal to:
- detect a situation of over-run;;
- check the plausibility of the signal
from the accelerator potentiometer
CLUTCH PEDAL SWITCH
A switch (2) on the clutch pedal is connected to pin 61 of the injection control unit.
The injection control unit uses the "brake pedal operated" signal to distinguish gear engaged and gear
shift conditions.
PRESSURE RELIEF SENSOR
The sensor is fitted to the intake manifold and
the signal sent to the injection control unit is
used to:
- regulate injection pressure;
- regulate injection duration.
The figure alongside shows the sensor and
electrical connector with the following pin-
out:
1. pressure signal
2. Earth
3. Fuel feed system
ATMOSPHERIC PRESSURE SENSOR
The atmospheric pressure signal is built into the injection control unit. It is responsible for measuring at­
mospheric pressure in order to correct measured air flow and reference air flow values to control the EGR
function.
Copyright by Fiat Auto 17

Marea- Marea Weekend 9 ™
2000 range (Q)
4F019XJ01
1. Impeller
2. Volumes
3. Intake port
4. Outlet port
5. Rollers
6. Outer race
7. Pressure relief valve
4F019XJ02
Engine
Fuel feed system
10.
SUBMERGED FUEL PUMP ASSEMBLY
(AUXILIARY) AND LEVEL GAUGE CON­
TROL
The assembly consists mainly of:
- a roller-type fuel pump;
- a fuel level gauge;
- a fuel filter
The submerged fuel pump is volumetric type
with rollers and a motor with brushes and
permanent magnet excitation.
Impeller (1) is driven by the electric motor to
turn and create volumes (2) that move from
intake port (3) to outlet port (4).
These volumes are delimited by rollers (5) that
adhere to outer race(6) as the motor turns.
The pump is fitted with two valves: a check
valve to prevent the fuel circuit emptying
(with the pump off); a second pressure relief
valve (7) that short-circuits the outlet to the
inlet when pressures exceed 5 bars.
FUEL FILTER
The fuel filter is located in the engine bay.
The filter is cartridge type with a filter element
(1) made up of a pack of paper discs with a
filtering area of some 5300 cm 2 and a filter
gauge of 4 - 5 microns.
The filter is equipped with a fuel preheating
device (2) controlled by the engine control
unit via a relay.
The control unit activates or deactivates the
diesel filter on the basis of a diesel tempera­
ture signal sent by sensor (3) on the filter.
A plug (4) screwed to the base of the fuel
filter cartridge is used to drai off the water.
The plug incorporates a sensor for the detec­
tion of water in the diesel filter connected to a
warning light on the instrument panel.
1. Filter cartridge
2. Diesel preheating device
3. Diesel temperature sensor
4. Water drain plug with sensor to detect
presence of water in diesel filter
Copyright by Fiat Auto 19

Engine
Fuel feed system
Marea- Marea Weekend W)JTD
2000 range ©
INERTIA SAFETY SWITCH
To increase car occupant safety in the case of
impact, the car is fitted with an inertia switch
located inside the passenger compartment se­
cured to the inside of the left panel.
This sensor reduces the possibility of fire (due
to emerging fuel) by deactivating the auxiliary
fuel pump that supplies the injection circuit.
The switch consists of a steel ball, fitted in a
tapered housing, kept in place by the attrac­
tion force of a permanent magnet.
In the case of violent impact, the ball is released from the magnetic detent and opens the normally closed
(NC) electrical circuit to cut off the auxiliary fuel pump connection to earth, and as a consequence the
supply to the injection system.
To restore the auxiliary pump earth connection, move back the seat and press the switch until a click is
heard.
Even after an apparently slight impact, if there is a smell of fuel or there are leaks from the fuel
system, do not turn the switch back on, but search for the fault and remedy it to prevent the risk
of fire.
'N.C. N.A. C
Inertia switch components
1. Inertia switch assembly
2. Sheath
3. Button
4. Upper side
5. Engagement side
6. Permanent magnet
7. Permanent magnet seat
8. Steel ball
C Common terminal
N.C. Normally closed contact
N.A. Normally open contact
22 Publication no. 506.763/24

Marea- Marea Weekend 9 *°
2000 range @)
Engine
Fuel feed system
10.
1. Undo the bolts (1) fixing the expansion
joint to the E.G.R. valve, disconnect the
pipe connecting the pneumatic valve and
the solenoid valve, then undo the bolts (3)
and remove the throttle casing.
2. At the bench, undo the bolts (1) and
separate the expansion joint from the throt­
tle casing.
The pneumatic valve (2) is secured to the
throttle casing.
E.G.R. VALVE
Removing-refitting
- Remove the throttle casing, following the
description in the previous paragraph.
3. Loosen the bolts (1) fixing the pipe con­
necting the E.G.R. and the heat exchanger.
4. Disconnect the electrical connection (1) for
the E.G.R. valve self-adjustment motor; undo
the bolts (2) fixing the E.G.R. valve to the
intake manifold, then lift up the valve and
remove the bolts fixing the pipe connected to
the heat exchanger (loosened previously).
Copyright by Fiat Auto VI 01 i ndate 31