1991 MITSUBISHI ECLIPSE fuel

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.

14-50FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>THROllLE
POSITION SENSOR ADJUSTME!-T’“.
(1) Slacken the accelerator cable enough.
6FU13%(2) Connect a digital voltmeter between terminal 19 (throttle
position sensor output voltage) of the engine control unit
and terminal 24 (ground).
(3) 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 V(4) If it is out of specification adjust by loosening the throttle
position sensor mounting screws and rotating the throttle
position sensor. After adjustment, tighten the screws
firmly.
NOTE1. Clockwise rotation of the throttle position sensor
increases the output voltage.
2.For information concerning the removal and installationof the throttle body, refer to
P.14-89.(5) Set the ignition switch at OFF.
(6) Adjust the free play of the accelerator cable.
(7) Remove the voltmeter.
(8) Disconnect the negative battery cable, and reconnect it
more than
10 seconds later. (By doing so, the memory
storing the diagnosis data during the idle speed control
adjustment is cleared.)

FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>14-51THROTTLE BODY (THROTTLE VALVE AREA)
CLEANINGNl4FtU
(1) Warm up the engine, then stop it.
(2) Remove the air intake hose from the throttle body.
(3) Plug the bypass passage inlet of the throttle body.
CautionDo not allow cleaning solvent to enter the bypass
passage.(4) Spray cleaning solvent into the valve through the throttle
body intake port and leave it for about 5 minutes.
(5) Start the engine, race it several times and idle it for about 1minute. If the idling speed becomes unstable (or if the
engine stalls), slightly open the throttle valve to keep the
engine running.
(6) If the throttle valve deposits are not removed, repeat steps
(4) and (5).
(7) Unplug the bypass passage inlet.
(8) Attach the air intake hose.
(9) Disconnect the battery terminal for 10 seconds or more,
and then reconnect it.
(lO)Adjust the basic idle speed. (Refer to P.14-48.)
RELEASE OF RESIDUAL PRESSURE FROM HIGH
PRESSURE FUEL HOSE
N14FGAFRefer to
P.14-44.FUEL PUMP OPERATION CHECK
N14FDAG(1) Set the ignition switch at OFF.
(2) Check that when the battery voltage is directly applied to
the fuel pump check terminal, the operating sound of the
pump can be heard.
NOTESince the high pressure 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.
I(3) Hold the high pressure fuel hose between your fingers and
check that the fuel pressure can be felt.

14-52FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>
IDLE POSITION SWITCH ADJUSTMENT
Caution
N14UDAThe idle position switch has been adjusted by the manu-
facturer.Do not, therefore, disturb the setting of the idle-position
switch.
If the setting is disturbed as a result of carelessness, or if
the idle-position switch is replaced, make the necessary
setting as described below.
(1) Sufficiently loosen the tension of the accelerator cable.
(2) Disconnect the connector of the idle position switch (fixed
speed adjusting screw).
(3) Loosen the lock nut of the idle position switch (fixed speed
adjusting screw).
(4) Sufficiently loosen the idle position switch by turning it in
the counterclockwise direction and fully close the throttle
valve.Caution
Be sure to completely close the throttle valve.
(5) Connect a tester (ohm range) between the switch’s
terminal and the body.
(6) Turn down the idle position switch until it enter the “ON”
state where the switch establishes a continuity to body
(this point is called “touch point”). Turn the switch down
15/16 of a turn more from that point.
NOTEThe “touch point” refers to the point where the throttle
valve begins opening.
(7) While holding the idle position switch to make sure that it
does not turn, tighten the lock nut.
(8) Adjust the accelerator cable.
(9) Adjust the basic idle speed. (Refer to P.14-48.)
(lO)Setting the throttle position sensor.
FUEL PRESSURE TESTN14FNAO(1) Reduce the fuel pressure in the fuel line.
(Refer to
P.14-44.)(2) Disconnect the high pressure fuel hose from the delivery
pipe.Caution
Cover the hose connection with shop towel to prevent
splash of fuel that could be caused by residual pressurein the fuel pipe line.
(3) Remove the throttle body stay.

FUEL SYSTEM - Service Adjustment Procedures <2.0L Enaine>14-53
MD998709
MD998742
I
FU01571-(4) 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.
(5) Install the special tool, which was set in place in step
(4),
between the delivery pipe and the high-pressure fuel hose.(6) Connect the
0 terminal of the battery.
(7) 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.
(8) Start the engine and run at curb idle speed.
(9) Disconnect the vacuum hose from the pressure regulator
and clog the vacuum hose end. Measure the fuel pressure.Standard value:
Turbo>330-350 kPa (47-50 psi) at curb idle

250-270 kPa (36-38 psi) at curb idle

290-320 kPa (41-46 psi) at curb idle
(10)Measure the fuel pressure when the vacuum hose is
connected to the pressure regulator:
Standard value:
Approx. 270
kPa (38 psi) at curb idle
Approx.
190 kPa (27 psi) at curb idle
Approx. 230
kPa (33 psi) at curb idle

14-54FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>
(11)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.
(12)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.
(13)lf the results of the measurements made in steps (9) and
(10) above are not within the standard value, use the table
below to determine the probable cause, and then make the
necessary repair.
Condition
Fuel pressure too lowProbable causeRemedy
a. Clogged fuel filtera. Replace fuel filter.
b. Fuel leaking toward return port due tob. Replace fuel pressure regulator.
improper seating of valve in fuel pressure
regulator
c. Low delivery pressure of fuel pumpc. Replace fuel pump.
Fuel pressure too higha. Stuck valve in fuel pressure
a. 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 nipplea. Repair or replace vacuum hose or
vacuum hose connected
nipple.
not different from fuel
pressure with vacuumb. Stuck valve in fuel pressure regulator or
b. Replace fuel pressure regulator.
hose not connecteddefective valve seating
(14)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.
Condition
Fuel pressure drops
slowly after engine is
stopped.Probable cause
Leakage from injectorRemedy
Replace injector.
Fuel pressure drops
im-Check valve in fuel pump does not closeReplace fuel pump.
mediately after engine is
stopped.
(15)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 towel to prevent
splash of fuel that could be caused by residual pressurein the fuel pipe line.
(17)Mount a new O-ring in the groove at the end of the high
pressure fuel hose.

FUEL SYSTEM - Service Adjustment Procedures <2.0L Engine>14-55
(18)Connect the high-pressure fuel hose,,to the delivery pipe
and tighten the screws to the specified torque.
(19)Check for fuel leaks.
@I Apply battery voltage to the fuel pump check terminal
to operate the fuel pump.
@ With fuel pressure acting, check the fuel line for leaks.
A
E2li:>
/ )
Engine speed (rpm)lFU4l6EGR VALVE CONTROL VACUUM CHECK
NlQFVBBlCheck Condition
Engine 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 CHECK
Check Condition
N14FVBClEngine 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.
Engine speed (rpm)3FU262(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.