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D
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4
AILY
URO
Cold starting
If even just one of the three temperature sensors (water, air
or diesel) records a temperature lower than 10°C, pre-post
heating is activated.
When the key makes contact the pre-heating indicator light
comes on and stays on for a length of time that varies in
relation to the temperature (while the glow plugs in the
cylinder head heat the air), then flashes. It is now possible to
start up the engine.
When the motor is running this indicator light goes out, while
the glow plugs continue to be powered for a certain length of
time (variable) for post-heating.
If, with the indicator light flashing, the engine is not started up
within 20-25 seconds (inattention time), the operation is
cancelled so as not to run down the batteries pointlessly.
The pre-heating curve is also variable in relation to the battery
voltage.
Warm starting
If the reference temperatures all exceed 10°C, when the key
makes contact the indicator light comes on for approximately
2 sec., for a short test, and then goes out. It is now possible to
start up the engine.
Run up
When the key makes contact, the control unit transfers the
information stored in memory when the engine was last
stopped into the main memory (see After Run) and makes a
diagnosis of the system.
After run
Whenever the engine is switched off with the key, the control
unit stays powered for a few seconds by the main relay.
This makes it possible for the microprocessor to transfer some
data from the main memory (volatile) to a non-volatile
memory, which can be erased and written over (EEPROM),
so as to make it available at the next start up (see Run Up).
These data basically consist of:
- various settings (engine idling adjustment, etc.);
- settings of some components;
- fault memory.
The process lasts a few seconds, typically from 2 to 7
(depending on the amount of data to save), after which the
ECU sends a command to the main relay and makes it
disconnect from the battery.
NOTE
It is extremely important for this procedure not to
be broken off, for example by switching off the
engine with the battery cut-out, or by disconnecting
the battery cut-out before 10 seconds have passed
since switching off the engine.
If this happens, the functioning of the system is
ensured, but repeated interruptions may damage
the control unit.
Print 603.93.651
Cut-off
This function cuts off fuel delivery when the vehicle is
decelerating (accelerator pedal released).
Cylinder balancing
Individual cylinder balancing contributes to increasing comfort
and handling.
This function permits individual, customized control over the
delivery of fuel and the start of delivery for each cylinder, even
differently from one cylinder to another, to compensate for
the hydraulic tolerances of the injector.
The differences in flow (delivery specifications) between the
various injectors cannot be evaluated directly by the control
unit. This information is supplied by Modus reading the bar
code of each injector at the time of assembly.
Synchronization search
If there is no signal from the camshaft sensor, the control unit
is anyhow able to recognize the cylinders into which the fuel
is to be injected.
If this occurs when the engine is already running, the
combustion sequence has already been acquired, so the
control unit continues with the sequence on which it has
already been synchronized.
If this occurs when the machine is at a standstill, the control
unit energizes a single solenoid valve. Within at most 2 turns
of the crankshaft, injection will take place in that cylinder, so
the control unit just needs to get synchronized on the firing
sequence and to start up the engine.
297
F1C ENGINE
Base - March 2006
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