Fiat 1998 Marea Weekend, Service Manual

Page: 296 / 846

Engine
'fuel system
16v
Marea- Marea Weekend ft
99 update
Wiring connector
AIR FLOW METER
The air flow meter is the hot wire type and is
incorporated in the butterfly casing.
The upper part contains a duct parallel to the
main flow in which the heated filament is lo-
cated.
Part of the flow of intake air is introduced into
the duct and, after having passed through it, it
comes out of the opposite side, rejoining the
main flow.
As a result, only part of the mass of air which
passes through the flow meter is measured:
this quantity is, however, proportional to the
overall mass passing through the flow meter.
The flow meter electrical output voltage is
therefore representative of the total flow rate.
This type of flow meter has two advantages
compared with the full flow type:
- considerable insensitivity to the pulsing effect
of the columns of air, present especially at
Iwo speeds and heavy loads;
- less fouling of the filament, thanks to the re-
duced mass of air coming into contact with
it; as a result the control unit has no wire
cleaning strategy (burn-in).
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Print n° 506.763/15
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