Fiat 1998 Marea Weekend, Service Manual

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Marea- Marea Weekend 9
99 update
Engine
Fuel system
10.
The pump is the volumetric type and is designed to run on unleaded fuel. The rotor is driven by a d.c.
electric motor supplied with the battery voltage directly by the twin relay operated by the control unit in
order to ensure:
- that the pump cuts out if the engine speed goes below a minimum level (around 450 rpm);
- the timed operation (around 15 seconds) each time the ignition is turned to the ON position and the
engine is not started up;
- operation when the engine has been started.
1. Negative
2. Fuel system
3. Supply
4. Pre-filter
The pump is equipped with an excess pressure valve which short circuits the supply with the inlet if the
pressure in the supply circuit exceeds 5 bar to prevent the electric motor from overheating.
In addition, a one-way valve fitted on the supply prevents the entire fuel circuit from being drained when
the pump is not working.
The nominal flow rate of the pump varies according to the speed of the rotor and consequently the supply
voltage.
Fuel filter
The fuel filter is contained in the pump housing and does not require periodic replacement
Fuel pressure regulator
This is a differential diaphragm device, regu-
lated during manufacture to a pressure of
3.50±0.05 bar and located in the top part of
the drip tray.
The pressurized fuel (1), coming from the
pump, exerts a force on the flow valve (3) op-
posted by the calibrated spring (2). When the
calibration pressure is exceeded, the valve
opens and the excess fuel (4) returns to the
tank, thereby stabilizing the pressure in the cir-
cuit.
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