Mazda 1990 323 Workshop Manual Supplement page 62

F
FUEL SYSTEM
Transfer Pump Control
FUEL IN LEFT TANK
,
J
4x4 CONTROL UNIT
(FUEL PUMP CONTROL
UNIT)
NO FUEL IN LEFT TANK
TRANSFER
/
TRANSFER PUMP
PUMP SWITCH: OFF
4x4 CONTROL UNIT 4x4 CONTROL UNIT
(FUEL PUMP CONTROL
UNIT)
-
1
/
TRANiFER PUMP
XANSFER PUMP SWITCH: ON
DELAY TIMER FUNCTION
CONTACT POINT LE"EL,mj=
TRANSFER PUMP SWITCH
TRANSFER PUMP E&-j
Fuel in left tank
The transfer pump switch is OFF, and the transistor within the fuel pump control unit is ON.
As a result, current flows to the coil, the switch is switched ON, and the transfer pump is activated.
No fuel in left tank
The transfer pump switch is ON, and the transistor within the fuel pump control unit is OFF.
As a result, the current to the coil is interrupted, the switch is switched OFF, and the transfer pump is stopped.
When in this condition, if the vehicle were driven on a rough road surface, the fuel level would vary up and
down and fuel pump would switch ON and OFF.
The transfer pump would then operate excessively, shortening the pump life. In order to prevent this, a ten-
second delay circuit is provided within the fuel pump control unit.
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F-8