1991 MITSUBISHI ECLIPSE engine

14-42FUEL SYSTEM - Service Adjustment Procedures C1.8L Engine>
6FU13%
Idle speed control
adjusting screw(3) Connect a digital voltmeter between terminal 19 (throttle
position sensor output voltage) of the engine control unit
kand terminal 24 (ground).
(4) Set the ignition switch at ON (without starting the engine)
hold it in that position for more than 15 seconds or more.
(5) Set the ignition switch at OFF.
(6) Disconnect the connectors of the idle speed control servo
and lock the idle speed control plunger at the initial position.(7) Back out the fixed SAS enough.
(8) Start the engine and let it run at idle.
(9) Check to ensure that the engine is running at the standard
basic idle speed.
Basic idle speed:
700&50 rpm
CautionLr1. On a new vehicle [driven less than 500 km
(380miles)], the engine speed may ‘be 20 to
100 rpm
lower, but no adjustment is necessary.
2.If the engine stalls or the engine speed is low after
the vehicle has been driven a distance of 500 km
(300 miles) or more, a deposit on the throttle valve
area is suspected. Clean the throttle valve area.
(10)lf the engine speed does not conform to the standard
value, adjust it with the idle speed control adjusting screw.
Caution
When adjusting the idle speed control, use a hexagon
wrench whenever possible.
(11)Turn in the fixed SAS .until the engine speed rises. Then
back out the fixed SAS until the “touch point” where the
engine speed does not fall any longer is found. Back out thefixed SAS an additional half a turn from the touch point.
(12)Stop the engine.
(13)Set the ignition switch at ON (do not start the engine) and
check that the output voltage from the throttle position
sensor is as specified.
Standard value:
0.48-0.52 VA

FUEL SYSTEM - Service Adjustment Procedures <1.8L Engine>14-43
(14)lf it is out of specification, adjust by loosing the throttle
position sensor mounting screws and rotating the throttle
position sensor. After adjustment, tighten the screws
firmly.
NOTEClockwise rotation of the throttle position sensor increases
the output voltage.
Throttle position
sensor
t-/ /I
(15)Set the ignition switch at OFF.
(16)Adjust the free play of the accelerator cable.
(17)Reconnect the connectors of the idle speed control servo.
(18)Remove the voltmeter.
(19)Start the engine and check that the engine is running at thecurb idle speed.
Curb idle speed:
700f 100 rpm
(20)Set the ignition switch at OFF, disconnect the negative
battery cable and reconnect it more than
10 seconds later
(By doing so, the memory storing the diagnosis data duringthe idle speed control adjustment is cleared.)
(21)Restart the engine, let it run at idle for about 5 minutes, andcheck that the engine is running in good idle quality.
THROTTLE BODY (THROTTLE VALVE AREA)
CLEANING
NllRCK
(1) Warm up the engine, then stop it.
(2) Remove the air intake hose from the throttle body.
(3) Spray cleaning solvent into the valve through the throttle
body intake port and leave it for about 5 minutes.
(4) Start the engine, race it several times and idle it for about 1minute. If the idling speed becomes unstable slightly open
the throttle valve to keep the engine running.
(5) If the throttle valve deposits are not removed, repeat steps
(3) and (4).
(6) Attach the air intake hose.
(7) Disconnect the battery terminal for
10 seconds or more,
and then reconnect it.
(8) Adjust the idle speed control and throttle position sensor.

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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FUEL SYSTEM - Service Adjustment Procedures <1.8L Engine>14-47
A
E3x>
/ )Engine speed
(rpm)1 FU446Engine speed (rpm)
>3FU262EGR VALVE CONTROL VACUUM CHECK

Check ConditionEngine coolant temperature: 85-‘95”C (185-205°F)
(1) Disconnect the vacuum hose from the throttle body EGR
vacuum nipple and connect a hand vacuum pump to the
nipple.(2) Start the engine and check to see that, after raising the
engine speed by racing the engine, vacuum raises pro-
portionately with the rise in engine speed.
NOTEIf there is a problem with the change in vacuum, it is
possible that the throttle body port may be clogged and
require cleaning.
PURGE PORT VACUUM CHECKCheck ConditionN14FvBcEngine coolant temperature:
85-95°C (185-205°F)
(1) Disconnect the vacuum hose from the throttle body purge
hose nipple and connect a hand vacuum pump to the
nipple.(2) Start the engine and check to see that, after raising the
engine speed by racing the engine, vacuum remains fairly
constant.NOTE
If there is no vacuum created, it is possible that the throttlebody port may be clogged and require cleaning.

14-48FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>
SERVICE ADJUSTMENT PROCEDURES
<2.0L DOHC Engine>
CURB IDLE SPEED INSPECTION
Caution
N14FHADThe improper setting (throttle valve opening) will increase
exhaust gas temperature at deceleration, reducing
catalys-tic converter life greatly and deteriorating exhaust gas
cleaning performance. It also has effect on fuel ‘consump-
tion and engine braking.
Pre-conditions for inspection
l Engine coolant temperature:
85-95°C (185-205°F)
l Lights, electric cooling fan and accessories: OFF
lTransaxle: Neutral (P for vehicles with automatic transaxle)l Steering wheel: Neutral position (vehicles with a power-
steering)l Check ignition timing and adjust if necessary. Refer to
GROUP 8.
NOTEWith vehicles for Canada, the headlights and taillights, etc.
remain on even when the lighting switch is turned OFF, but thiscauses no problems during inspection.
(1) Connect the tachometer to the engine speed detection
terminal.
(2)Run the engine for more than 5 seconds at an engine speedof 2,000 to 3,000 rpm.
(3) Run the engine at idle for 2 minutes.
(4) Read the idling rpm. If it is not within the specified speed,
check the idle speed control system.
Curb idle speed:
750f 100 rpm
NOTE1. Adjustment of the idling speed is usually unnecessary,
because this system controls the idling speed.
2.For rpm, one-half of the actual engine rpm is indicated,so the actual engine rpm is two times the indicated
value shown by the tachometer.
BASIC IDLE SPEED ADJUSTMENT
N14FHBIPre-conditions for inspection
l Engine coolant temperature:
85-95°C (185-205°F)
l Lights, electric cooling fan, and accessories: OFF
lTransaxle: Neutral (P for vehicles with automatic transaxle)l Steerig wheel: Neutral position (vehicles with a
power-
steering)(1) Connect a tachometer.

FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>14-49
TerminalNo.10screw(2) Disconnect the female connector (for waterproof protec-
tion of the connector) from the connector for ignition timing
adjustment.
(3) Connect the ignition timing adjusting terminal to the groundusing a jumper wire with alligator clips.
(4) Connect terminal No.
10 of the self-diagnosis connector to
the ground with a jumper wire with alligator clips.
(5) Start the engine and run at idle.
(6) Check to be sure that the engine idling speed is the basic
idle speed.
Basic idle speed: 750
250 rpm
If there is a deviation of the engine speed from the basic
idle speed, first determine whether or not the conditions
described below exist, and then use the speed adjustment
screw to adjust to the basic idle speed.
(a) The engine speed may be
20-100 rpm low for a
new vehicle [driven about 500 km (300 miles) or
less], but adjustment is not necessary.
(b) If engine stalling occurs or the engine speed is low
even though the vehicle has been driven about 500
km (300 miles) or more, it is probable that these are
deposits adhered to the throttle valve, so it should
be cleaned.
(Refer to
P.14-51.)(c) If the engine speed is higher than the standard
value even though the speed adjusting screw is
fully close, check for any indication that the idle
position switch (fixed speed adjusting screw) posi-
tion has changed; if there is such an indication,
adjust the idle position switch (fixed speed adjust-
ing screw).
If there is no evidence of a change of position, it is
probable that there is leakage resulting from de-
terioration of the fast-idle air valve (FIAV), so
replace the throttle body.
(7) Turn OFF the ignition switch and stop the engine.
(8) Disconnect the grounding jumper wire from the diagnosis
connector.(9) Disconnect the grounding jumper wire from the ignition
timing connector and mount a waterproof connector.
(1O)Disconnect the tachometer.
(11)Star-t the engine once again and let it idle for about 5
minutes; check to be sure that the idling condition is
normal.