ignition FIAT MAREA 2001 1.G User Guide

Marea- Marea Weekend 9* Engine
2000 range (Q) Fuel feed system
10.
LOCATION OF INJECTION/IGNITION SYSTEM COMPONENTS IN THE ENGINE COMPART­
MENT
1 2345678 9
Key
1. Active charcoal filter
2. Anti-evaporation solenoid valve
3. Intake air pressure and temperature sensor
4. Engine idle adjustment stepping motor on
throttle casing
5. Throttle valve position sensor on throttle cas­
ing
6. System relay feed
7. Protective fuse
8. Throttle case
9. Maxi-fuse protecting I.E. system (EFI)
10. Speedometer sensor
11. Engine management control unit
12. Coolant temperature sensor
13. Ignition coil
14. Injectors
15. Rpm and TDC sensor
16. Timing sensor
17. Spark plugs
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Marea- MareaWeekend • ** Engine
2000 range @ . . Index
10.
. Page
FUEL FEED SYSTEM
- Engine management system 1
- Location of injection/ignition system
components 2
- Location of diagnostic socket 2
- Removing-refitting accelorometer 3
- Removing-refitting front Lambda sensor 3
- Removing-refitting rear Lambda sensor 4
- Removing-refitting heat shield 5
- Removing-refitting catalytic converter 7
Copyright by Fiat Auto

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
Copyright by Fiat Auto 1

Engine
Fuel feed system
Marea-Marea Weekend ®> *»
2000 range @)
10.
LOCATION OF INJECTION/IGNITION SYSTEM COMPONENTS
Key
1. Variable valve timing control solenoid
2. Injectors
3. Fuel vapour cut-out solenoid valve
4. Injection/ignition control unit
5. General system protective fuse
6. Flow meter/air temperature sensor
7. Motorized throttle body
8. Engine coolant temperature sensor
9. Vehicle speed sensor
10. Variable geometry manifold actuator solenoid
valve
11. RPM sensor
12. Front Lambda sensor connector
13. Ignition coil
14. Timing sensor
15. Rear Lambda sensor connector
16. Detonation sensors
17. Accelerometer
LOCATION OF DIAGNOSTIC SOCKET
The diagnostic socket for the analysis of the en­
gine management system is located under the
junction unit in the dashboard. This socket also
makes a connection with the diagnostic equip­
ment (Examiner or other instruments) for the
other electronic control units on the vehicle.
It is a "standardized" 16-way diagnostic socket
which can be connected to the diagnostic equip­
ment using the "MPX97" adaptor.
2 Print n° 506.763/23

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

Fuel feed system
Engine Marea- Marea Weekend 9 ™
2000 range (Q)
10.
Control of idle speed
On the basis of signals from the rpm sensor and engine coolant temperature sensor, the injection control
unit controls the pressure governor and alters the injector control times to maintain idle speed stable at all
times.
Under certain conditions, the idle speed control unit also considers battery voltage.
Control of maximum speed limitation
According to rpm level, the injection control unit limits maximum speed by means of two types of inter­
vention:
- as maximum speed approaches, it reduces the amount of fuel injected to reduce line pressure;
- when maximum speed is exceeded, it inhibits operation of the auxiliary pump and injectors.
Control of maximum torque limitation
On the basis of rpm level, the injection control unit computes limit torque and maximum permitted fume
index parameters on the basis of predefined, stored maps.
It then corrects the above parameters using engine coolant temperature and car speed data. The resulting
values are then used to modulate the amount of fuel to be injected by adjusting the pressure regulator and
injectors.
Control of fuel temperature
The injection control uint is kept constantly informed of fuel temperature by a sensor on the return mani­
fold.
If fuel temperature exceeds a set value (about 110 °C), the control unit reduces line pressure by adjusting
the pressure governor, leaving injection times unaltered.
Control of coolant temperature
The injection control unit is constantly informed of coolant temperature by a sensor on the thermostat.
If engine coolant temperature or air conditioning fluid pressure exceeds certain levels, the control unit
performs the following actions:
- It reduces the amount of fuel injected by adjusting the pressure governor and injectors (power reduc­
tion);
- it controls the engine radiator cooling fan.
Control of glow plugs
The injection control unit controls operation of the glow plug preheating control unit to bring the tem­
perature in the combution chambers up to levels that promote fuel self-ignition and thus make start-up
easier.
The control unit controls the operation of the glow plug control unit for a certain time both before (pre­
heating) and after (postheating) engine start-up and also controls activation of the warning light on the
control panel.
Preheating, postheating and glow plug warning light activation times vary according to engine coolant
temperature.
4 Publication no. 506.763/24

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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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 ©) 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
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Engine Marea- Marea Weekend 9*nD
Fuel feed system 2000 range (§)
10.
THROTTLE BODY
To reduce engine noise during shut-down, a throttle has been added to the intake port with the aim of
closing off the air flow to the cylinders.
Throttle valve opening or closure is controlled by an engine control unit (5) that manages a control ac­
tuator (3) on throttle body (4) via solenoid (2).
Operation
When the engine is off, the throttle is open because no vacuum is present.
When the engine is running, the throttle is open because the Pierburg solenoid is not activated and pre­
vents the vacuum reaching the pneumatic actuator.
A vacuum builds up in the tank during engine operation.
During engine shut-down (when the ignition key is turned OFF), the control unit keeps the actuator sup­
ply relay activated for a further 4 or 5 seconds and simultaneously earths the Pierburg valve. The Pierburg
valve opens to send the vacuum that has built up in the vacuum tank to the pneumatic actuator, which
closes the throttle to cut off the flow of air to the cylinders.
4F024XJ01
1. Vacuum tank;
2. Pierburg solenoid controlling throttle body
actuator;
3. Pneumatic actuator on throttle body
4. Throttle body
5. Engine control unit
6. Vacuum pump
24 Publication no. 506.763/24