Page 111 of 330

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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Page 112 of 330

Engine
Fuel feed system
JTD Marea- Marea Weekend 9
2000 range @
10.
Operation at high rotation speeds
When the engine speed is increased, the ki
netic energy of the exhaust gases increases
gradually.
As a result, the speed of the turbine (5) in
creases and consequently the supercharging
pressure.
The VGT solenoid valve (2) operated by the
injection control unit (1), through the actuator
(4) causes the moving vanes to change posi
tion until the maximum opening position is
reached.
1. Injection control unit
2. VGT solenoid valve
3. Vacuum reservoir
4. Pneumatic actuator
5. Turbine
There is therefore an increase in the passage
sections and consequently a slowing down in
the flow of exhaust gases which pass through
the turbine (1) at the same speed or slower
than the low speed conditions.
The speed of the turbine (1) decreases and
settles down at a suitable vaule for the correct
operation of the engine at high speeds.
1. Turbine
2. Moving vanes
3. Pneumatic actuator
4. Rotary seal
TURBOCHARGER (1910 JTD 100 CV)
It basically consists of two impellers (1) on
one shaft (2) which rotates on floating bear
ings lubricated by a duct (3) from the engine
lubrication circuit.
The oil used dissipates some of the large
amount of heat given off by the exhaust gases
at the turbine.
There is a waste gate valve (4) fitted on the
turbocharger, operated by a pneumatic actua
tor (5), that makes it possible to shutter the
flow of exhaust gases to the turbine, accord
ing to the engine power/torque requirements.
The pneumatic actuator is controlled by the en
gine management control unit via a solenoid
valve.
* The turbocharger used on the 1910 JTD 100 CV version is the fixed geometry type.
26 VI 0^ Cam.frtfi and ri!plact<& Print n° 506.763/25
Page 139 of 330
Marea-Marea Weekend Electrical equipment
2000 range (§) Location of components on the car
55.
LOCATION OF RELAYS AND FUSES ON THE VEHICLE (BONNET - Petrol engine types)
Fi998l152B 273 274 i * *
3B-3C Power fusebox
96 Power fuse protecting ABS
98 Headlamp washer intermittent function
122 Engine cooling fan low speed relay
123 Engine cooling fan high speed timer
124 Air condiitoning compressor control relay
129 Power fuse protecting engine coling fan
150 Injection system relay feed
151 Lambda probe control relay for fuel pump
and injectors
152 Fuse protecting injection system
152A Fuse protecting injection system
152B Fuse protecting injection system
273 Fuse protecting automatic transmission
system
274 Fuse protecting automatic transmission
system
276 Starter enablement relay
(••) Versions with air conditioning
(*) With automatic transmission
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Page 186 of 330

Marea-Marea Weekend Electrical equipment
2000 range (§) Wiring diagrams
55.
DESCRIPTION
Engine types
DESCRIPTION 10i 0) c.a. 01/70
ANTI-LOCKING BRAKING SYSTEM (ABS) AND FAILURE WARNING LIGHT 67 67 67 67
STARTING - ELECTRONIC IGNITION AND INJECTION - RECHARGING AND WARNING LIGHT - INSUFFICIENT ENGINE OIL PRESSURE WARNING LIGHT - INJECTION SYSTEM FAILURE WARNING LIGHT -
REV COUNTER 69 69 — 71
STARTING - ELECTRONIC INJECTION - RECHARGING AND WARNING LIGHT - LOW ENGINE OIL PRESSURE WARNING LIGHT - HEATER PLUGS WARNING LIGHT - INJECTION SYSTEM FAILURE WARNING
LIGHT - FUEL PREHEATING — — 73 —
STARTING - EGR CONTROL - INJECTION CONTROL - HEATER PLUGS AND WARNING LIGHT - RECHARGING AND WARNING LIGHT - LOW ENGINE OIL PRESSURE WARNING LIGHT — — — —
AUTOMATIC TRANSMISSION - SYSTEM FAILURE WARNING LIGHT — 75 — —
DIAGNOSTIC SOCKECT CONNECTIONS 77 77 77 77
PREPARATION FOR TAXI 79 79 79 79
FM.B. The numbers in the table correspond to the page number of the electrical system in the manual
Copyright by Fiat Auto III
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