exhaust FIAT MAREA 2000 1.G User Guide

Marea- Marea Weekend •
2000 range ©
16v Engine
Fuel feed system
10.
1. Loosen the belt tension using the lock nut
(2) and the adjustment screw (1); then re­
lease the belt from the pulley.
2. Undo the bolts fixing the bracket for the
power assisted steering pump mounting
and detach the pump.
3. Undo the nuts fixing the exhaust manifold
to the cylinder head and detach the mani­
fold.
- To refit, reverse the order of the operations
carried out for the removal; tension the
power assisted steering pump drive belt,
using the adjustment screw; use tool
189576200 to check that the tension is
between 32 and 45 daN.
ELECTRIC FUEL PUMP WITH LEVEL
SENDER UNIT
Removing-refitting
- Disconnect the negative battery terminal.
- Lift up the lining in the luggage compart­
ment and remove the fuel pup protective
cover.
- Disconnect the electrical connection for the
electric pump assembly and the fuel supply
and breather pipes.
4. Undo the ring nut fixing the electric fuel
pump to the tank using tool 1870736000.
The gasket on the tank housing should be
replaced each time the pump drip tray is
removed-refitted.
NOTE The position of the fuel pump is fixed
and is established by a reference in
the housing in the tank which sou Id
correspond to the projection on the
pump drip tray.
Copyright by Fiat Auto 7

Marea- Marea Weekend & Engine
2000 range (§) Fuel feed system
ENGINE MANAGEMENT SYSTEM
Foreword
The Marea-Marea Weekend 1998 20v is equipped with a 5 cylinder in line engine with 20 valves, 1998
cc, twin overhead camshaft and a Bosch ME3.1 integrated electronic injection/ignition system.
The fuel system differs from the one described for the 1998 20v "99 range" version through the addition
of several variants to make it compatible with the EEC Stage 3 EOBD regulations.
The main modifications to the system can be summarized as follows:
- Catalytic converter near the exhaust manifold to take maximum advantage of the heat of the gases.
- Two Lambda sensors, one upstream (front) and one downstream (rear) which check the quality of the
exhaust gases and the operation of the catalyzer.
- Adoption of an accelerometre sensor on the right shock absorber turret, used to distinguish between
engine torque variations doe to the uneveness of the road surface and those due to failed ignition in
the combustion chamber (misfire).
- Adoption of a timing sensor on the inlet side timing pulley.
- Multi-purpose valve on the tank to prevent leaks.
- Adoption of raipd attachment connectors for the anti-evaporation system pipes.
- Cap on the fuel filler with an attachment cable.
For further information on the fuel system, refer to publication 507137.
DIAGRAM SHOWING ENGINE EXHAUST ASSEMBLY
4F001WJ01
Key
1. Exhaust manifold
2. Catalytic converter
3. Front Lambda sensor
4. Rear Lambda sensor
5. Silencers
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Marea- Marea Weekend 9
2000 range ©
Engine
Fuel feed system
10.
REMOVING-REFITTING CATALYTIC
CONVERTER
Removing
- Position the vehicle on a lift.
- Disconnect the negative battery terminal.
- Remove: the upper and lower heat shields,
the front and rear Lambda sensors, carrying
out the operations described in the relevant
chapters.
- Lower the lift.
1. Undo the fixing nuts (1a) and separate the
catalytic converter (1b) from the exhaust
manifold (1c).
E
Nuts la: 3.2 daNm
- Raise the lift.
2. Undo the fixing nuts (1a) and separate the
exhaust pipe (1 b).
EI
Nuts 1a: 4.2 daNm
3. Undo the nuts (1a) and the bolts (1b) and
remove the bracket (1c).
E
E
Nuts 1a: 2.5 daNm
Bolts 1b: 2.5 daNm
- Remove the catalytic converter.
Refitting
- Reverse the order of the operations carried
out for the removal.
Copyright by Fiat Auto 7

Marea- Marea Weekend 9 \) JTD
2000 range O
Engine
Index
FUEL SYSTEM
- Introduction
- System management strategies
- Fuel system functional diagram
- Diagram showing information ente­
ring/leaving the control unit and
sensors/actuators
INJECTION SYSTEM WIRING DIA­
GRAM
- Injection electronic control unit
- Rpm sensor
- Timing sensor
- Air flow meter
- Injectors
- Engine coolant temperature sensor
- Fuel temperature sensor
- Fuel pressure sensor
- Heater plugs control unit
- Accelerator pedal potentiometer
- Brake pedal switch
- Clutch pedal switch
- Excess pressure sensor
- Atmospheric pressure sensor
page
1
1
1
2
8
10
12
13
13
14
15
15
15
16
16
17
17
17
17
THROTTLE CASING
- Removing-refitting
E.G.R. VALVE
- Removing-refitting
E.G.R. VALVE SELF-ADJUSTMENT
MOTOR
- Removing-refitting
E.G.R. VALVE HEAT EXCHANGER
- Removing-refitting
SOLENOID VALVE ON VACUUM
RESERVOIR FOR THROTTLE CA­
SING PNEUMATIC VALVE
- Removing-refitting
VACUUM RESERVOIR
- Removing-refitting
10.
page
30
31
32
32
34
34
FUEL SUPPLY CIRCUIT 18
- Immersed (auxiliary) pump and fuel
gauge assembly 19
- Fuel filter 19
- Pressure pump 20
- Fuel pressure regulator 20
- Multifunction valve 21
- Supply manifold (rail) 21
- Inertia safety switch 22
AIR SUPPLY CIRCUIT 23
- Throttle case 24
- Turbocharger 25
SUPERCHARGING PRESSURE
CONTROL SOLENOID VALVE
- Removing-refitting 35
FUEL FILTER
- Removing-refitting 35
PRESSURE REGULATOR
- Removing-refitting 36
EMISSION CONTROL DEVICES 27
- Oxidizing catalytic converter 27
- Exhaust gas recirculation circuit
(EGR) 27
- Recirculation circuit for crankcase
vapours (blow-by) 29
Copyright by Fiat Auto VI 01 Cancels anil replaces

Marea- Marea Weekend © ™ Engine
2000 range Q Fuel feed system
10.
FUEL SYSTEM
INTRODUCTION
Marea and Marea Weekend 1.9 JTD cars are equipped with a 4 cylinder in line, 1910 cc turbodiesel en­
gine with two valves per cylinder, an overhead camshaft, turbocharger and intercooler and electronic in­
jection.
The fuel system ensures correct engine operation and can be divided into the following subsystems:
- Fuel feed circuit with common rail injection;
- air feed circuit;
- exhaust circuit;
- blow by vapour recirculation circuit;
- Exhaust Gas Recirculation (EGR) circuit
Operation of the various circuits making up the fuel system is optimised by an electronic control system
managed by a special control unit.
The main feature of the fuel system is common rail fuel injection. Common rail is a higher pressure elec­
tronic injection system for fast direct injection diesel engines.
The main features of the common rail system are as follows:
- availability of high injection pressures (up to 1350 bars);
- possibility of modulating these pressures (from a minimum of 150 bars to a maximum of 1350 bars)
independently of engine speed (rpm) and engine load;
- ability to operate at high engine speeds (up to 6000 rpm);
- precise injection control (injection advance and duration);
- reduced fuel consumption;
- reduced emissions.
FUEL SYSTEM MANAGEMENT STRATEGIES
The management program (software) is stored inside the control unit memory and consists of a series of
strategies, each of which manages a precise system control function.
Through the use of information providd by the various sensors (input), each strategy processes a set of
parameters based on data stored in special control unit memory areas. It then controls system actuators
(output), i.e. the devices that allow the engine to operate.
The main purpose of these management strategies is to determine the exact amount of fuel to be injected
into the cylinders with timing (injection advance) and pressure designed to achieve the best possible en­
gine performance in terms of power, fuel consumption, fumes, emissions and handling.
The main system management strategies are essentially as follows:
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of injected fuel quantity;
of injection advance;
of injection pressure;
of auxiliary fuel pump;
of injection during over-run (cut-off);
of idle speed;
of maximum speed limitation;
of maximum torque limitation;
of fuel temperature;
of engine coolant temperature;
of air turbocharging pressure;
of glow plugs;
of exhaust fumes;
of exhaust gas recirculation (EGR);
of climate control system activation;
control of engine immobiliser operation (Fiat
CODE);
self-diagnosis
Copyright by Fiat Auto 1

Engine
Fuel feed system
Marea- Marea Weekend © ™
2000 range ©
10.
FUEL SYSTEM OPERATING DIAGRAM
1. Pressure pump
2. Electrically-controlled EGR valve
3. Flow meter
4. Pressure regulator
5. Fuel filter
6. Instrument panel
7. Glow plug preheating control unit
8. Electronic control unit
9. Injection system relay
10. Return manifold (low pressure)
11. RPM sensor
12. Glow plugs
13. Engine coolant temperature sensor
14. Potentiometer on accelerator pedal
15. Switch on brake pedal
16. Switch on clutch pedal
17. Variable geometry turbocharger
18. Timing sensor
19. Injectors
20. Fuel pressure sensor
21. Variable geometry turbocharger control sole­
noid
22. Auxiliary fuel pump
23. Glow plug preheating warning light
24. System failure warning light
25. Pressure relief sensor
26. Fuel temperature sensor
27. Throttle valve
28. Variable geometry actuator
29. Vacuum tank
30. Exhaust gas heat exchanger
2 Publication no. 506.763/24

Ma tea- Marea Weekend 9 ™
2000 range (Q) Fuel feed system
Engine
10.
Control of injected fuel quantity
The control unit controls the fuel pressure regulator and injectors on the basis of output signals from the
accelerator pedal potentiometer, flow meter and rpm sensor.
The timing and thus the injection sequence are determined when the engine is started up using signals
from the rpm and timing sensor (synchronisation stage); injection timing is then implemented using the
rpm sensor signal alone and considering a injection sequence of 1 -3-4-2.
The control unit inhibits injection in the following cases:
- fuel pressure level greater than 1500 bars;
- fuel pressure level lower than 120 bars;
- engine speed higher than 6000 rpm.
When the engine has warmed up, maximum injection duration (injector opening time) is 1500 ns, but it
can reach 3000 ns during the start-up stage.
Control of injection advance
The electronic control unit determines injection advance mainly on the basis of the quantity of fuel to be
injected.
The injection advance is then corrected on the basis of coolant temperature and speed in order to com­
pensate for ignition delays due to low temperatures in the combustion chamber during warm-up.
The optimum injection point is also processed to ensure driving comfort and emission limits laid down by
Euro 3 legislation.
Control of injection pressure
This control is of particular importance because injection pressure influences the following parameters:
- amount of fuel taken into the cylinders for the same injection time duration;
- injected fuel nebulation;
- spray penetration;
- lag between electrical control to injection and actual injection start and end times.
The above parameters engine behaviour significantly, particularly in terms of power output, exhaust emis­
sions, noise levels and handling.
The injection control unit controls the pressure governor on the basis of engine load to obtain an optimal
line pressure at all times.
When the engine is cold, injection pressure is corrected on the basis of engine speed and engine coolant
temperature to meet engine needs at different operating temperatures.
Control of auxiliary fuel pump
The auxiliary fuel pump submerged in the tank is supplied by the injection control unit by means of a relay
when the ignition key is turned on.
Fuel supply to the pump is inhibited when one of the following condition occurs:
- when the ignition has been turned on for a certain length of time without the engine running;
- if the inertia switch cuts in.
Control of injection during over-run (cut-off)
The fuel cut-off strategy is implemented when the injection control unit receives information that the ac­
celerator pedal has been released from the potentiometer.
Under these conditions, the control unit cuts off the fuel supply to the injectors and restores it before idle
speed is reached.
Copyright by Fiat Auto 3

Marea-Marea Weekend 9]
2000 range (j§)
I) JTD
Fuel feed system
Engine
10.
Exhaust fumes control
Through this function the injection control unit limits any exhaust fumes that could be produced during
transition speeds.
To satisy these requirements the control unit processes the signals supplied by the accelerator pedal po­
tentiometer, the rpm sensor and the air flow meter and controls the fuel pressure regulator and the injec­
tors to meter the correct amount of fuel to inject.
Exhaust gas recirculation control
On the basis of the signals supplied by the rpm sensor, intake air quantity sensor, engine coolant tempe­
rature sensor and accelerator pedal position sensor, the control unit calculates the operating times for the
EGR valve so that the exhaust gases are partly recirculated in certain engine operating conditions in line
with Euro 3 pollution control standards.
Air conditioning system engagement control
The injection control unit manages the operation of the air conditioning system compressor electro­
magnet coupling following a logic aimed at preventing operating conditions that would adversely affect
engine performance.
- When the compressor is switched on the injection control unit increases the quantity of fuel during
idling to allow the engine to adjust to the increased power requirements and momentarily interrupts the
supply to the compressor in high engine power requirement conditions (strong acceleration).
Engine immobilizer function control
The system is equipped with an engine immobilizer function. This function is achieved through the pre­
sence of a specific control unit (Fiat CODE), capable of conversing with the injection control unit and an
electronic key with a special transmitter for sending a recognition code.
Each time the key is turned to the OFF position, the Fiat CODE system completely deactivates the injecti­
on control unit.
When the key is turned to the ON position the following operations take place, in order:
1. the injection control unit (whose memory contains a secret code) sends the Fiat CODE control unit a
request to send the secret code to deactivate the immobilizer functions;
2. the Fiat CODE control unit responds by only sending the secret code after, in turn, having received the
recognition code transmitted by the ignition key;
3. the recognition of the secret code allows the deactivation of the injection control unit immobilizer func­
tion and its normal operation.
Autodiagnosis
The complete electronic fault diagnosis of the injection system is carried out by connecting the special
equipment (EXAMINER or EXAMINER PLUS) to the standardized diagnostic socket (EOBD).
The system is also equipped with a self-diagnostic function which recognizes, memorizes and signals any
faults.
If a fault is detected in the sensors or actuators, the recovery strategy is immediately activated in order to
ensure that the engine functions at an acceptable level. The vehicle can be driven to a service centre for
the appropriate repairs to be carried out.
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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
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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
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