FIAT MAREA WEEKEND FIAT MAREA 2000 1.G Repair Manual

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

Marea- Marea Weekend <§l ™
2000 range ©
Engine
Fuel feed system
TZZZZZZZZZZZZZZZZZZb
TZZZZZZZZZZZZZZ*
10.
MULTIFUNCTION VALVE
The multifunction valve is located on the fuel
tank and performs the following functions:
- tank pressurisation
- ventilation
- seal if the car rolls over
Tank pressurisation
Tank pressurisation is maintained at a level be­
tween 55 and 75 mbars by means of a valve
mounted on a sealing rim.
The valve is supported by a steel plate and held in place by a spring.
When tank pressure exceeds a specified level, it overcomes spring resistance and allows the valve to rise
so that vapours can flow out.
When the pressure returns to within specified limits, the valve closes again
Ventilation
Under certain car service conditions, a vacuum may build up in the tank due to the effect of:
- heat changes;
- fuel consumption
in this case, the valve's function is to make up pressure inside the tank by letting air into the tank.
If this function is not performed correctly, the car may judder or stall due to difficulties in supplying the
pump.
Seal if the car rolls over
The roll-over function prevents fuel emerging from the tank if the car rolls over or tilts to a great extent.
During normal car operation (bends, acceleration, braking etc.), the fuel slops about and may emerge.
The highly-sensitive roll-over valve prevents this happening.
DELIVERY MANIFOLD (RAIL)
The delivery manifold (rail) is fitted to the cylinder head on the intake side.
Its volume damps fuel pressure fluctuations due mainly to:
- operation of the pressure pump;
- injector opening.
A fuel pressure sensor is fitted in the middle of the delivery manifold.
Hydraulic connections (high pressure) are via special steel pipes.
Copyright by Fiat Auto 21

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 0 *° Engine
2000 range @ Fuel feed system
10.
EMISSION CONTROL DEVICES
The car is equipped with devices designed to reduce polluting emissions in accordance with Euro 3
reguirements:
- Oxidising catalytic converter (1)
- Exhaust gas recirculation circuit (EGR) (2)
- Crankcase blow-by vapour recirculation circuit (3).
4F027XJ01
OXIDISING CATALYTIC CONVERTER
The oxidising catalytic converter is a post-
treatment device used to oxidise CO, HC and
particulate and convert them to carbon dioxide
(C02) and water vapour (H20).
The catalytic converter consists of a ceramic
honeycomb case (1) with its chambers im­
pregnated with platinum, a substance that
catalyses oxidation reactions.
Exhaust gases flow through the chambers and
heat the catalytic converter where they trigger
the conversion of pollutants to inert com­
pounds.
The chemical reaction involved in oxidising
the CO, HC and particulate is effective at tem­
peratures between 200 °C and 350 °C.
Above 350 °C, the sulphur in the diesel begins
to oxidise to produce sulphur dioxide and sul­
phuric acid.
EXHAUST GAS RECIRCULATION CIRCUIT (EGR)
This system sends a proportion of exhaust gases to the intake under certain engine service conditions.
This dilutes the fuel mixture with inert gsaes to lower.peak temperature in the combustion chamber; This
helps limit the formation of nitrogen oxides (NOx) and reduces exhaust levels by 30-50%.
4F027XJ02
Copyright by Fiat Auto 27

Marea-Marea Weekend
2000 range (j§)
1
4F029XJ02
Engine
Fuel feed system
10.
RECIRCULATION CIRCUIT FOR CRANK-
CASE VAPOURS (BLOW-BY)
The control of the oil vapour emissions is
achieved through a separator (1) (function
carried out by the tappet cover) which collects
the vapours released by the crankcase in the
pipe (2).
The difference in temperature between the
separator and the oil vapours causes partial
condensation.
The vapours which have not condensed are
sent, via the pipe (3), to the turbocharger air
intake hose.
The adjustment valve, consisting of a spring
(1) and a diaphragm (2), on the tappet cover
makes it possible to prevent intake.
When the vacuum values inside the tappet
cover exceed a pre-set limit, the diaphragm
moves downwards sealing the duct from the
crankcase.
Copyright by Fiat Auto 29

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

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

Ma tea- Marea Weekend 9 m
2000 range ©)
Engine
Fuel feed system
10.
1. Undo the fixing nuts (1) and remove the
vacuum reservoir.
SOLENOID VALVE CONTROLLING
SUPERCHARGING PRESSURE
Removing-refitting
- Position the vehicle on a lift, then discon­
nect the negative battery lead.
2. Working from underneath the vehicle, dis­
connect the electrical connector (1) and
the pipes (2).
3. Press the retaining tab on the rear of the
mounting bracket and release the solenoid
valve.
FUEL FILTER
Removing-refitting
4. Disconnect the electrical connections (1)
from the fuel filter and the supply and re­
turn pipes to the tank and the supply pipes
to the pump (2), then undo 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.
Copyright by Fiat Auto oi upjdin 35