2001 FIAT MAREA comp

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

Marea- Marea Weekend 9 ™
2000 range ©) Fuel feed system
Engine
10.
Compents of injection system wiring diagram
1. Vehicle speepd
2. Rev counter
3. Engine radiator fan low speed relay
4. Radiator fan high speed activation relay
5. Potentiometer on accelerator pedal
6. Timing sensor
7. Fuel pressure sensor
8. EGR system modulator solenoid
9. Fuel pressure regulator
10. Glow plug preheating warning light on control panel
11. Injection system failure warning light
12. Air conditioning system relay
13. Coolant temperature sensor
14. Rpm sensor
15. Fuel temperature sensor
16. Diagnostic socket
17. Fiat CODE control unit
18. Four stage pressure switch
19. Injection electronic control unit
20. Pressure relief sensor
21. 7.5A fuse protecting electronic injection system ( + 15 power supply from ignition switch)
22. 7.5A fuse protecting electronic injection system ( + 30 power supply from ignition switch)
23. Main injection system relay
24. 30A fuse protecting injection system
25. Auxiliary fuel pump relay
26. Glow plug preheating control unit
27. Intake air flow and temperature sensor (debimeter)
28. Brake pedal switch
29. Clutch pedal switch
30. Ignition switch
31. Battery
32. Inertia switch
33. Auxiliary fuel pump (submerged in tank)
34. 60A fuse protecting glow plug control unit
35. Cylinder no. 1 glow plug
36. Cylinder no. 2 glow plug
37. Cylinder no. 3 glow plug
38. Cylinder no. 4 glow plug
39. Cylinder no. 1 injector
40. Cylinder no. 2 injector
41. Cylinder no. 3 injector
42. Cylinder no. 4 injector
43. Throttle valve control solenoid
44. Variable geometry turbocharger control solenoid
45. Diesel filter heater relay
Copyright by Fiat Auto 9

Marea- Marea Weekend 9"°
2000 range ©
Engine
Fuel feed system
10.
TIMING SENSOR
The Hall effect sensor is fitted to the cylinder head and faces the camshaft pulley.
An opening on the pulley allows the timing sensor to detect the engine timing position and indicate it to
the injection control unit.
The injection control unit uses the timing sensor signal to detect TDC at the end of compression.
Operation
A semi-condulator layer, through which a current passes, immersed in a magnetic field (lines of force per­
pendicular to the direction of the current), produces a difference in power, known as Hall voltage.
If the intensity of the current remains constant, the voltage produced only depends on the intensity of the
magnetic field. The intensity of the field can simply be altered periodically to produce a modulated electri­
cal signal. Signal frequency is proportional to the speed with which the magnetic field changes.
To achieve this change, the sensor is crossed by a metal ring (inner part of the pulley) with an opening.
When it moves, the metal part of the ring covers the sensor to magnetic field and the output signal is
therefore low; Conversely, the sensor generates a high signal at the opening when the magnetic field is
present.
This signal, together with the rpm and TDC signals, allows the injection control unit to identify piston po­
sition and determine injection point.
AIR FLOW METER
(DEBIMETER)
The debimeter is located on the air intake
sleeve and is hot film type.
The debimeter contains an intake air tem­
perature sensor.
Operation
The principle of operation is based on a
heated membrane fitted into a measurement
channel through which engine intake air
flows.
The hot film membrane is maintained at a
constant temperature (about 120 °C higher
than incoming air) by the heater coil.
The mass of air flowing through the measure­
ment channel tends to take heat from the
membrane. To keep the membrane at constant
temperature, a certain current level must flow
through the resistance.
Because this current is proportional to the
mass of air that flows to the engine, it can be
measured with a Wheatstone bridge and the
resulting signal is sent to the injection control
unit.
1. Covers
2. Electronic card
3. Sensor
4. Mounting plate
5. Mount
6. o-ring
7. Temperature sensor
Copyright by Fiat Auto 13

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 Engine
2000 range ©) Fuel feed system
10.
AIR INTAKE CIRCUIT
The air intake circuit is turbocharged by means of of a GARRET variable geometry turbocharger and an
intercooler.
The turbocharger is low inertia type. Its design is based on a new principle of turbocharging whereby the
turbocharger aims to increase torque within the range of most frequent use (e.g. at low speeds).
After passing through the filter (1), intake air is compressed by the exhaust gas-drive turbocharger (4),
cooled by intercooler (5) and sent to throttle body (6) and the intake manifold from where it is distributed
to the cylinders.
Air intake circuit diagram
4F023XJ01
1. Intake vent
2. Air filter
3. Intake airflow meter (debimeter)
4. Variable geometry turbocharger
5. Air-air intercooler
A. To turbocharger
B. To intake manifold
6. Throttle body
Copyright by Fiat Auto 23

Marea- Marea Weekend 9
2000 range ©
Engine
Fuel feed system
10.
TURBOCHARGER (1910 JTD 110 CV)
The turbocharger used in the application of the
EURO 3 standards in the variable geometry
type connected to the exhaust manifold.
The turbocharger is controlled by the engine
management control unit via a duty-cycle so­
lenoid valve.
The increased volumetric output for the engine
is achieved, in the case of variable geometry
compressors, through the use of:
- a centrifugal compressor (1)
- a turbine (2)
- a series of moving vanes (3)
- a pneumatic actuator (4) controlling the
moving vanes.
- asolenoid valve (5) controlling the actuator
The variable geometry turbocharger makes it
possible to:
- increase the speed of the exhaust gases in
the turbine at low engine speeds
- slow down the speed of the exhaust gases
in the turbine at high speeds.
The control of the speed (kinetic energy) of
the exhaust gases makes it possible to pro­
duce increased engine torque at low speeds
and greater maximum power at high speeds.
Operation at low rotation speeds
When the engine is operating at low speeds,
the exhaust gases possses little kinetic energy:
under these circumstances a conventional tur­
bine would rotate slowly, supplying a limited
supercharging pressure.
On the other hand, in the variable geometry
turbine (1), the moving vanes are in the
maximum closure position and the small pas­
sage sections between the vanes increase the
speed (C) of the intake gases.
Increased intake speeds lead to increased pe­
ripheral speeds (U) of the turbine and, conse­
quently, the compressor.
The speed of the gases inside the impeller is
indicated by the vector (W).
1. Turbine
2. Moving vanes
3. Pneumatic actuator
4. Rotary seal
Copyright by Fiat Auto r VI-01-Cancels arwl replaces.25

Marea- Marea Weekend 9
2000 range ©
Engine
Fuel feed system
Open the band (1) retaining the oil vapour
recovery pipe, then undo the bolts (2) fix­
ing the E.G.R. valve heat exchanger
mounting bracket.
Undo the nut (1), located under the ther­
mostat, fixing the heat exchanger.
Disconnect the band (1) retaining the cool­
ant pipe for the heat exchanger.
Undo the bolts shown in the diagram and
remove the thermostat to allow the subse­
quent extraction of the heat exchanger.
Remove the heat exchanger from the en­
gine compartment.
Copyright by Fiat Auto VK01 - Update ,f 33

Engine
Fuel feed system
Marea- Marea Weekend 9 ™
2000 range ©
SOLENOID VALVE ON VACUUM RES­
ERVOIR FOR THROTTLE CASING
PNEUMATIC VALVE
Removing-refitting
- Disconnect the negative battery lead, then
remove the sound insulation shield follow­
ing the instructions in the previous para­
graphs.
1. Disconnect the electrical connections (1)
at the fuel filter and the supply and return
pipes (2) at the reservoir and the supply
pipe to the pump, then loosen the nuts (3)
fixing the fuel filter mounting. Lift up the
filter and disconnect the electrical connec­
tion (4) for the water in the diesel sensor.
- Release the power assisted steering fluid
supply pipe from the reservoir to the pump
from the retaining band.
2. Disconnect the pipe (1) connected to the
vacuum reservoir and the pipe (2) con­
nected to the vacuum intake pipe from the
solenoid valve. Disconnect the electrical
connector (3), then undo the fixing bolts
(4) and remove the solenoid valve.
VACUUM RESERVOIR
Removing-refitting
- Disconnect the negative battery lead, then
remove the sound insulation shield and the
fuel filter, following the instructions in the
previous paragraphs.
- Release the power assisted steering fluid
supply pipe from the reservoir to the pump
from the retaining band.
3. Disconnect the pipe (1) connected to the
vacuum reservoir and the pipe (2) con­
nected to the vacuum intake pipe from the
solenoid valve. Disconnect the electrical
connector (3), then undo the fixing bolts
(4) and remove the bracket, complete with
solenoid valve, for the throttle casing
pneumatic valve.
34 VI-01 Update IN Print n° 506.763/25