fuel pump MITSUBISHI ECLIPSE 1991 User Guide

FUEL SYSTEM - Troubleshootina
<2.0LDOHC Engine>
FunctronArr-fuellgnrtronIdleAir con-
FuelFuel
PurgeEGRmixturetimrng
speeddrtronerpump pressureaircontrc
controlcontrol
controlpowerdrivecontrol
control
relaycontrol
Functronal elementscontrol
InPower supplyXXXXXXXXPut(ignrtron switch coupled)
Power supply (battery backup)
Ix Ix Ix lx lx lx lx Ix
Top dead center sensorI xXI
1 Crank angle sensorIxlxIxIxIxI lxlx
Oxygen sensorI x I
Vehrcle speed sensor
Air conditioner switch
XX
XX”XPower steering
011 pressure switchXIDetonation sensor
lgnrtron switch
X
XXX
lgnrtron switch ST terminalXXX
lnhibrtor switch XXX”
)ut-InjectorXutResistor X
Idle speed control servoX
Power transistorI 1x1 I I I I I
Arr condrtroner power relay
Control relay
Fuel pressure control valve
Purge control solenord valve
X
X
X
X
EGR control solenoid valveX
NOTE*:

FUEL SYSTEM - Troubleshootinn
MPI CIRCUIT1.8L
Engine
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FUEL SYSTEM - Troubleshooting
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FUEL SYSTEM - Troubleshooting14-21
2.0L DOHC Engine (Non-Turbo)-_
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MAIN
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X36-AC-UOSlB-NC

FUEL SYSTEM - Troubleshooting2.0L DOHC
Engine (Non-Turbo)
II'SIBLE
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4 E-47
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FUEL SYSTEM - Troubleshooting
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FUEL SYSTEM - Service Adjustment Procedures 4.8L Engine>
RELEASE OF RESIDUAL
PRESSURE FROM HIGHPRESSURE FUEL HOSE
N14FGAE
MD998709
MD998742
IFUO157Make the following operations to release the pressure remain-
ing in fuel pipe line so that fuel will not flow out.
(1) Disconnect the fuel pump harness connector at the fuel
tank rear side.
(2) Start the engine and after it stops by itself, turn the ignition
switch to OFF.
(3) Disconnect the battery
(-) terminal.
(4) Connect the fuel pump harness connector.
FUEL PUMP OPERATION CHECK
Nl4FDAG(1) Set the ignition switch at OFF.
(2) Check that when the batten/ voltage is directly applied to
the fuel pump check terminal, the operating sound of the
pump can be heard.
NOTESince the fuel pump is installed in the fuel tank, its
operating sound cannot be readily heard. Remove the fuel
tank cap and listen to the operating sound through the filler
port.(3) Hold the high pressure fuel hose between your fingers and
check that the fuel pressure can be felt.
FUEL PRESSURE TEST
Nl4FNAN(1) Reduce the fuel pressure in the fuel line.
(2) Disconnect the high pressure fuel hose from the delivery
pipe.
CautionCover the hose connection with shop towel to prevent
splash of fuel that could be caused by residual pressurein the fuel pipe line.
(3) Connect a fuel pressure gauge to the special tool (hose
adapter).Use a suitable O-ring or gasket between the fuel pressure
gauge and the special tool so as to seal in order to preventfuel leakage at this time.
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FUEL SYSTEM - Service Adjustment Procedures 4.8L Engine>14-45(4) Install the special tool, which was set in place in step
(3),
between the delivery pipe and the high pressure fuel hose.(5) Connect the
0 terminal of the batten/.
(6) Apply battery voltage to the fuel pump check terminal and
activate the fuel pump; then, with fuel pressure thus
applied, check to be sure that there is no fuel leakage fromthe pressure gauge or the special tool connection part.
(7) Start the engine and run at curb idle speed.
(8) Disconnect the vacuum hose form the pressure regulator
and clog the vacuum hose end. Measure the fuel pressure.Standard value:
330-350 kPa (47-50 psi) at curb idle
(9) Measure the fuel pressure when the vacuum hose is
connected to the pressure regulator:
Standard value: Approx. 270
kPa (38 psi) at curb idle
(10)Race the engine repeatedly in two or three series. Then
check that the fuel pressure does not fall when the engine
is running at idle.
(11)Check to be sure that there is fuel pressure in the return
hose also (by gently pressing the fuel return hose with a
finger while repeatedly racing the engine).
NOTEThere will be no fuel pressure in the return hose when the
volume of fuel flow is not sufficient.
(12)lf the results of the measurements made in steps (8) and
(9) above are not within the standard value, use the table
below to determine the probable cause, and then make the
necessan/ repair.

14-46FUEL SYSTEM - Service Adjustment Procedures <1.8L Engine>
Condition
Fuel pressure too low
Fuel pressure too highProbable causea. Clogged fuel filter
b. Fuel leaking toward return port due to
Remedy
a. Replace fuel filter.
improper seating of valve in fuel pressure
b. Replace fuel pressure regulator.
regulatorc. Low delivery pressure of fuel pump
c. Replace fuel pump.
a. Stuck valve in fuel pressurea. Replace fuel pressure regulator.
regulator
b. Clogged or bent fuel return hose or pipeb. Repair or replace hose or pipe.
‘.
Fuel pressure witha. Clogged or broken vacuum hose or nipple
a. Repair or replace the vacuum hose or
vacuum hose connectednipple.
not different from fuel
pressure with vacuum
b. Stuck valve in fuel pressure regulator orb. Replace fuel pressure regulator.
hose not connecteddefective valve seating
(13)Stop the engine and check for change in fuel pressure
gauge indication, which should not drop.
If the gauge indication drops, observe the rate of drop and
determine and remove the causes according to the
following table.
ConditionProbable causeRemedy
Fuel pressure dropsLeakage from injectorReplace injector.
slowly after engine is
stopped.
rqFuel pressure drops im-Check valve in fuel pump does not closeReplace fuel pump.
mediately after engine is
stooped.
(14)Reduce the fuel pressure in the fuel line.
(16)Disconnect the high pressure fuel hose and remove the
fuel pressure gauge from the delivery pipe.
Caution
Cover the hose connection with shop tdwel to prevent
splash of fuel that could be caused by residual pressure
in the fuel pipe line.
(16)Mount a new O-ring in the groove at the end of the high
pressure fuel hose.
(17)Connect the high pressure fuel hose to the delivery pipe,
and tighten the screws to the specified torque.
(18)Check for fuel leaks.
@ Apply battery voltage to the fuel pump check terminal
to operate the fuel pump.
@ With fuel pressure acting, check the fuel line for leaks.
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