Mitsubishi 3000GT Service Manual page 185

OPERATION
Drives the fuel pump during cranking and engine operation.
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relay coil to ground. This turns on the MFI relay switch and drive power is supplied from the battery
through the MFI relay switch to the fuel pump.
While the engine is running, the engine control module keeps the power transistor on and energizes
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the MFI relay coil so that drive power is supplied to the fuel pump.
Fuel Pump Relay II Operation
Change the fuel pump discharge in two stages by ON-OFF operation of the relay switch for fuel
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pump relay II.
If the amount of inlet air is small (the engine load is low), the engine control module turns on the
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power transistor to energize the coil of fuel pump relay II, sending drive power to the fuel pump
through the resistor. If the amount of inlet air is large (the engine load is high), the engine control
module turns off the power transistor to send drive power directly to the fuel pump without passing
through the resistor.
INSPECTION
Using Scan Tool
<Fuel Pump>
Function
Actuator test 07
<Fuel Pump Relay lb
Function Item No.
Actuator test 13
HARNESS INSPECTION
MULTIPORT
On-Vehicle Inspection of MFI
FUEL INJECTION - Components
Check condition
Fuel pump is Engine cranking
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driven to cir- Forced drive of fuel
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Check is made for
above two conditions
Operation
Turn the fuel pump relay
II from OFF to ON
Check the fuel pump.
Apply battery voltage to the
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check terminal
checking terminal and oper-
ate the pump.
Check the ground circuit of the
fuel pump.
Fuel pump connector: Dis-
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connected
TSB Revision
Check item
Hold return hose with
fingers to feel pulsation
indicating fuel flow
Listen to pump operat- Operating sound
ing sound near fuel tank
Check condition
Ignition switch: ON Operating sound is
heard.
Pulsation is felt
is heard
Normal condition
Repair the
harness.
(B2 -
Ground)