engine MITSUBISHI DIAMANTE 1900 Repair Manual

4-42 DRIVEABILITYAND EMISSIONS CONTROLS
Emission control system vacuum hose
routing-1994-96 2.4L engine, Federal
emissions
Emission control system vacuum hose
routing-1994-96 2.4L engine, California
emissions
Emission control system vacuum hose
routing-1997 2.4L engine, Federal
emissions I Emission control system vacuum hose I routing-1997 2.4L engine, California I emissions
TV TbE
93154v25
I Emission control system vacuum hose I routing-1998 2.4L engine, Federal I emissions
93154v26
El
ro
el nission control system vacuum hose
uting-1998 2.4L engine, California
nissions
93154v24
Emission control system vacuum hose
routing-1999-00 2.4L engine
93154~26
Emission control system vacuum hose
routing-1992 3.OL engines (SOHC and
DDHC) w/traction control, California
emissions
93154v31
Imission control system vacuum hose
-outing-l992 3.OL engines (SOHC and
IOHC) w/out traction control, California
:missions

DRIVEABILITYAND EMISSIONSCONTROL-S 4-43
L. Light blue
R. Red
B Black Fuel pressure
regulator
. Vehicle front
93154~33
I Fuel pressure
regulator
Vehicle front
93154V34
Emission control system vacuum hose routing-1992 3.01 engines
Emission control system vacuum hose routing-1993-94 3.OL en-
(SOHC and OOHC) w/out traction control, Federal emissions
gines (SOHC and DOHC) w/out traction control, Federal emissions
R’ Red
0. Black Venlcle front
9315-M
Emission control system vacuum hose routing-1996-96 3.OL en-
gines (SOHC and DOHC) w/traction control, Federal emissions
Evaporatwe em~smn Traction control
vacuum so&old Tracuon control
purge solmold
, ,ventllatlon solmold
Emission control system vacuum hose routing-1993-94 3.OL en-
Evaporatwe ernmon
purge solenoid
L Light blue
R Red
B Black
Fuel pressure
regulator
Vehicle front
931W3E
imission control system vacuum hose routing-1992 3.OL engines
SOHC and DOHC) w/traction control, Federal emissions
Evaporawe emss~on
purge solenoid
EGR solmold
G Green
Y Yellow
L L,gnt blue
R Red
B 3lack Fuel oressure
regUlatOr
Vetme front
93154v42
imission control system vacuum hose routing-1995-96 3.OL en-
lines (SOHC and DOHC) w/out traction control, Federal emjgsions

4-44 DRIVEABILITYAND EMISSIONS CONTROLS
Emission control system vacuum hose
pouting-1993-96 3.OL engines (SOHC and
DOHC) w/traction control, California emis-
rions Emission control system vacuum hose
routing-1993-96 3.OL engines (SOHC and
DOHC) w/out traction control, California
emissions
Emission control system vacuum hose routing-1998 3.5L engine
Emission control system vacuum hose routing-199%00 3.5L engine
w/out traction control Emission control system vacuum hose
routing-1997 3.5L engine
Emission control system vacuum hose routing-1999-00 3.5L engim
Mtraction control
Emission control system vacuum hose routing-199940 3.OL engine

I
5-2, FUELSYSTEM
When there is a problem starting or driving a vehi-
“is there fuel? will often lead to solving most basic
cle, two of the most important checks involve the ig- problems. For ignition system diagnosis and testing,
nition and the fuel systems. The questions most me-
please refer to the information on engine electrical
chanics attempt to answer first, “is there spark?” and
components and ignition systems found earlier in this manual. If the ignition system checks out (there
is spark), then you must determine if the fuel system
is operating properly (is there fuel?).
REMOVAL&INSTALLATION
# See Figures 1 thru 7
The fuel lines used on all models covered by this
manual are quite straight forward. Typically the fit-
tings are either rubber hoses connecting to steel lines
with clamps, or steel lines connecting to steel lines
using retaining bolts or flare fittings. Several fittings
are unique such as the banjo-bolt fitting on the fuel
feed line from the fuel filter.
ventitateu area. Do not allow fuel spray or
vapors to come in contact with a spark or
ooen flame. Keen a drv chemical fire extin- Observe all applicable safety precautions
when working around fuel. Whenever servic-
ing the fuel system, always work in a well
___ _ . . . _
guisher near the’work &ea. Always keep fuel
in a container specifically designed for fuel
storage; also, always pmperly seal fuel con-
tainers to avoid the possibility of fire or ex-
plosion. Fig. 1 This photo of the fuel pump lines is
an example of the type of fittings found on
most models. The return line utilizes a rub-
ber hose and a hose clamp, while the feed
line utilizes a flare fitting
ren disconnect the hose from
1 the pressure regulator Fig. 2 This fitting on the fuel pressure reg-
ulator utilizes a rubber hose and a hose
clamp. Remove the hose clamp . . .
93153p45 Fig. 4 The fuel feed line-to-fuel rail fitting
is held by retaining bolts. Unfasten the
bolts . . .
Fig. 5 . . .
then remove the fuel feed line
from the fuel injector rail
I
1 Fig. 6 The fitting on the too of the fueg;?lz
I I
93155pzl Fig. 7 On the banjo-bolt type fitting, it is
ter utilizes a banjo-bolt type fitting. Re-
I I crucial that the copper washers are re-
move the bolt from the filter feed line on placed every time the fitting is removed
the top of the filter

FUELSYSTEM 513
l Always replace worn fuel fitting O-rings with
new. Do not substitute fuel hose or equivalent, where
I
The Multi-Point Injection (MPI) system is electroni-
rally controlled by the Engine Control Module (ECM),
based on data from various sensors. The ECM controls
the fuel flow, idle speed and ignition timing. fuel pipe is installed.
Fuel is supplied to the injectors by an electric in-
tank fuel pump and is distributed to the respective in-
jectors via the main fuel pipe. The fuel pressure ap-
plied to the injector is constant and higher than the
pressure in the intake manifold. The pressure is con-
trolled by the fuel pressure regulator. The excess fuel
is returned to the fuel tank through the fuel return pipe.
When an electric current flows in the injector, the
injector valve is fully opened to supply fuel. Since the
fuel pressure is constant, the amount of the fuel in-
jetted from the injector into the manifold is increased
or decreased in proportion to the time the electric
current flows. Based on ECU signals, the injectors in-
ject fuel to the cylinder manifold ports in firing order. Fuel injection systems remain under pres-
sure after the engine has been turned OFF.
Properly relieve fuel pressure before discon-
neeting any fuel lines. Failure to do so may
result in fire or personal injury.
1. Turn the ignition to the OFF position.
2. Loosen the fuel filler cap to release fuel tank
pressure.
I
The flow rate of the air drawn through the air
cleaner is measured by the air flow sensor. The air
enters the air intake plenum or manifold through the
throttle body. In the intake manifold, the air is mixed
with the fuel from the injectors and is drawn into the
cylinder, The air flow rate is controlled according to
the degree of the throttle valve and the servo motor
openings. The system is monitored through a num-
ber of sensors which feed information on engine con-
ditions and requirements to the ECM. The ECM cal-
culates the injection time and rate according to the
signals from the sensors,
Safety is the most important factor when perform-
ing not only fuel system maintenance but any type of
maintenance. Failure to conduct maintenance and re-
pairs in a safe manner may result in serious personal
injury or death. Maintenance and testing of the vehi-
cle’s fuel system components can be accomplished
safely and effectively by adhering to the following
rules and guidelines.
l To avoid the possibility of fire and personal in-
jury, always disconnect the negative battery cable un-
less the repair or test procedure requires that battery
voltage be applied.
l Always relieve the fuel system pressure prior to
disconnecting any fuel system component (injector,
fuel rail, pressure regulator, etc.), fitting or fuel line
connection. Exercise extreme caution whenever re- Observe all applicable safety precautions
when working around fuel. Whenever servic-
ing the fuel system, always work in a well
ventilated area. Do not allow fuel spray or va-
pors to come in contact with a spark or open
flame. Keep a dry chemical fire extinguisher
near the work area. Always keep fuel in a con-
tainer specifically designed for fuel storage;
also, always properly seal fuel containers to
avoid the possibility of fire or explosion.
3. For the Mirage, Diamante, and 1994-00
Galant, remove the rear seat cushion, then remove
the service cover and detach the fuel pump harness
connector.
4. For the 1990-93 FWD Galant, detach the fuel
pump harness connector located in the area of the
fuel tank. It may be necessary to raise the vehicle to
access the connector.
5. For the 1990-93 AWD Galant, remove the car-
pet from the trunk, locate the fuel tank wiring at the
pump access cover, then detach the wiring.
6. Start the vehicle and allow it to run until it
stalls from lack of fuel. Turn the key to the OFF posi-
tion.
7. Disconnect the negative battery cable, then at-
tach the fuel pump connector. Install the access .
cover, cushion or carpet as necessary.
8. Wrap shop towels around the fitting that is be-
ing disconnected to absorb residual fuel in the lines.
9. Place shop towels into proper safety container. Fig, 8 Detach the connector for the throttle
position (TP) sensor
93153ps5 Fig, 9 Remove the accelerator cable end
from the throttle lever
Fig. IO Remove the hose shown here from
lieving fuel system pressure to avoid exposing skin,
face and eyes to fuel spray. Please be advised that
fuel under pressure may penetrate the skin or any
part of the body that it contacts.
l Always place a shop towel or cloth around the
fitting or connection prior to loosening to absorb any
excess fuel due to spillage. Ensure that all fuel
spillage (should it occur) is quickly removed from
enginesurfaces. Ensure that all fuel soaked cloths or
towels are deposited into a suitable waste container.
l Always keep a dry chemical (Class B) fire ex-
tinguisher near the work area.
l Do not allow fuel spray or fuel vapors to come
into contact with a spark or open flame.
l Always use a backup wrench when loosening’
and tightening fuel line connection fittings. This will
prevent unnecessary stress and torsion to fuel line
piping. Always follow the proper torque specifica-
tions. REMOVAL &INSTALLATION
p See Figures 8 thru 18
1. Properly relieve the fuel system pressure as
outlined earlier in this section.
2. Drain the engine cooling system into a suit-
able container.
3. Matchmark the jocation of the adjuster bolt
on the accelerator cable mounting flange. This will
assure that the cable is installed in its original loca-
tion. Remove the throttle cable adjusting bolt and
disconnect the cable from the lever on the throttle
body. Position cable aside.

5-4 FUELSYSTEM
93155422 Fig. 12 Exploded view of the throttle body
and related components-l .5L engine
15-Z Nm
11-16 lt.lbs. 15-22 Nm 11-16 ft.lbr.
1. Connectnn for accelerator cable
2. Connection for breather hose
3 Connection for au intake hose
4 Connectton for au hose C
5. Connectton for vacuum hose
6 Connectton for IAC motor connector and
closed throttle posItIon swtch connector
7 ConnectIon for TPS connector
8 Connectton for water hose
9 Connectnon for water by-pass hose
10 Ground plate mounting screw
11. Throttle body stay and ground plate
12 Au flttlng
13 Gasket
14 Throttle body
15 Gasket ’
89575422 :ig. 14 Exploded view of the throttle body and related components-l.61 and 2.OL DOHC en-
line
93155g24 Yg. 15 Exploded view of the throttle body and related components- :ig. 16 Exploded view of the throttle body and related components-
1.OL SOHC engine, DOHC similar
1.5L engine
4. Remove the connection for the breather hose
10. Unfasten the throttle body mounting bolts, 14. If equipped, install the throttle body stay and
and the air intake hose from the throttle body and po-
then remove the throttle body from the engine. Re- QrOUnd plate. Secure with retainers tightened to
sition aside.
move and discard the gasket. 11-16 ft. Ibs. (15-22 Nm).
5. Tag and disconnect the necessary vacuum
To install: 15. Install the ground plate mounting screw.
hoses.
11. Clean all old gasket material from the both 16. Connect the water hoses to the throttle body.
6. Label and detach the electrical connectors at throttle body mounting surfaces. Install new gasket Install new hose clamps if required.
the throttle body, as necessary.
1 onto the intake manifold plenum mounting surface. 17. Attach the electrical and vacuum connectors
7. Disconnect the water and water by-pass
*Poor idling quality and poor performance to the throttle body, as tagged during removal.
hoses at the base of the throttle body.
may be experienced if the gasket is installed 18 Connect the accelerator cable to the throttle
8. If equipped, unfasten the ground plate
incorrectly. body and install the adjusting bolt in original posi-
mounting screws, then remove the throttle body stay
tion. Check adjustment of cable.
and QrOUnd plate from the engine.
12. Install the throttle body to the intake manifold 19 Install the air intake and breather hoses.
9. Remove the air fitting and
gasket. plenum and tighten the mounting bolts. 20. If removed, install the battery and connect the
13. Install the air fitting, if equipped, making sure positive cable.
new gasket iS in place.

FUEL SYSTEM 5-5,
21. Connect the negative battery cable. Refill the
cooling system.
REMOVAL & INSTALLATION
1.5L, 1.8L, And 2.OL SOHC Engines
ti See Figures 17, 18, and 19
1. Relieve the fuel system pressure as described
in this section.
2. Disconnect the PCV hose from the valve
cover. Also disconnect the breather hose at the oppo-
site end of the valve cover.
3. Remove the bolts holding the high pressure
fuel line to the fuel rail and disconnect the line. Be
prepared to contain fuel spillage; plug the line to
keep out dirt and debris.
Observe all applicable safety precautions
when working around fuel. Whenever servic-
ing the fuel system, always work in a well
ventilated area. 00 not allow fuel spray or
vapors to come in contact with a spark or
open flame. Keep a dry chemical fire extin-
guisher near the work area. Always keep fuel
in a container specifically designed for fuel
storage; also, always properly seal fuel con-
tainers to avoid the possibility of fire or ex-
plosion.
4. Remove the vacuum hose from the fuel pres-
sure regulator.
5. Disconnect the fuel return hose from the
pressure regulator.
6. Label and detach the electrical connectors
from each injector.
7. Remove the bolt(s) holding the fuel rail to the
manifold. Carefully lift the rail up and remove it with
the injectors attached. Take great care not to drop an
injector Place the rail and Injectors in a safe location
on the workbench; protect the tips of the injectors
from dirt and/or Impact.
8. Remove and discard the injector rnsulators
from the intake manifold. The insulators are not
reusable.
9. Remove the injectors from the fuel rail by
pulling gently in a straight outward motion. Make
certain the grommet and O-ring come off with the in-
jector.
To install: 10. Install a new insulator in each injector port in
the manifold.
11. Remove the old grommet and O-ring from
each injector Install a new grommet and O-ring; coat
the O-ring lightly with clean, thin oil.
12. If the fuel pressure regulator was removed,
replace the O-ring with a new one and coat it lightly
with clean, thin oil Insert the regulator straight into
the rail, then check that it can be rotated freely. If It
does not rotate smoothly, remove it and inspect the
O-ring for deformation or jamming. When properly
installed, align the mounting holes and tighten the
retaining bolts to 7 ft. Ibs. (9 Nm). This procedure
must be followed even if the fuel rail was not re-
moved.
13. Install the injector into the fuel rail, constantly
turning the injector left and right during installation.
1Hilt4naunfu(norc e Fu(l
:E%!,,.,.- 1: IEE
: Efgz tz!z? :: %%I
;P&.xmeaw 13 m
Fig. 17 Exploded view of the fuel injectors and related components-l .5L engine
I
.xs.
1 Connection for breather hose
2 Connection for PCV hose
3 Connection for high tm?ss”re fuel hose
4 0-ring
5 Connection for vacuum hose
6 Connecr~on for fuel return hose
7 Fuel pressure regulator
8 0-ring
9 Connection for control harness
10 Fuel ml
11 Insulator
12 insulator
13 lnlector
14 O-ring
15 Grommet
89575026
Fig. 19 Exploded view of the fuel injectors and related components-2.01 SOHC engine
When fully installed, the injector should still turn
freely in the rail. If it does not, remove the injector
and inspect the O-ring for deformation or damage.
14. Install the delivery pipe and injectors to the
engine. Make certain that each injector fits correctly
into its port and that the rubber insulators for the fuel
rail mounts are in position. 15. Install the fuel rail retaining bolts and tighten
* them to 9 ft. Ibs. (12 Nm).
16. Connect the wiring harnesses to the appro-
priate injector.
17. Connect the fuel return hose to the pressure
regulator, then connect the vacuum hose.
18. Replace the O-ring on the high pressure fuel
line, coat the O-ring lightly with clean, thin oil and

install the line to the fuel rail. Tighten the mounting
bolts,
19. Attach the PCV hose and the breather hose if
thev were disconnected.
20. Connect the negative battery cable. Pressur-
ize the fuel system and inspect all connections for
I
leaks.
1.6L and 2.01 DOHC Engines
b See Figure 20
1. Relieve the fuel system pressure as described
in this section.
2. Disconnect the negative battery cable.
3. Wrap the connection with a shop towel and
disconnect the high pressure fuel line at the fuel rail.
Observe all applicable safety precautions
when working around fuel. Whenever servic-
ing the fuel system, always work in a well
ventilated area. Do not allow fuel spray or
vapors to come in contact with a spark or
open flame. Keep a dry chemical fire extin-
guisher near the work area. Always keep fuel
in a container specifically designed for fuel
storage; also, always properly seal fuel con-
* tainers to avoid the possibility of fire or ex-
plosion.
4. Disconnect the fuel return hose and remove
the O-ring.
5. Disconnect the vacuum hose from the fuel
pressure regulator.
6. Disconnect the PCV hose. On 2.OL engine,
remove the center cover.
1 x Connection for PCV hose
2. Connection for high pressure fuel hose
3. O-ring
4. Connection for vacuum hose
5. Connection for fuel return hose
&2 I=, 1c.1 nrncc*.ra regu,ator
lble clamD
7. Label and detach the electrical connectors
from each iniector.
8. Accelerator ca
9. Center cover . 10. Connection for control harness
11 Fuel rail
12. Insulator
13. Insulator
14. Injector
15. O-ring
16. Grommet
89575g27 Exploded view of the fuel injectors and related
components -1.6L and 2.QL DOHC
5-6 FUELSYSTEM
8. Remove the injector rail retaining bolts, Make
sure the rubber mounting bushings do not get lost.
9. Lift the rail assembly up and away from the
engine.
10. Remove the injectors from the rail by pulling
gently. Discard the lower insulator. Check the resis-
tance through the injector. The specification for 2.OL
turbocharged engine is 2-3 ohms at 70°F (20°C).
The specification for the others is 13-15 ohms at
70°F (20°C). To install:
11. Install a new grommet and O-ring to the in-
jector. Coat the O-ring with light oil.
12. install the injector to the fuel rail.
13. Replace the seats in the intake manifold. In-
stall the fuel rail and injectors to the manifold. Make
sure the rubber bushings are in place before tighten-
ing the mounting bolts.
14. Tighten the retaining bolts to 72 inch lbs. (11
Nm).
Fig. 21 Remove the fuel feed line-to-fuel
rail retaining fitting bolts . . .
15. Attach the connectors to the injectors and in-
stall the center cover. Connect the PCV hose.
16. Connect the fuel pressure regulator vacuum
hose.
17. Connect the fuel return hose.
18. Replace the O-ring, lightly lubricate it and
connect the high pressure fuel line.
19. Connect the negative battery cable and check
the entire system for proper operation and leaks. Fig. 22 . . . then remove the fuel feed line
from the fuel injector rail
2.4L Engine
b See Figures 21 thru 30

FUELSYSTEM 5-7
Fig, 25 Remove the vacuum hose from the Fig. 25 Detach the connectors from all of
pressure regulator the fuel injectors
1 H; :A ..;lt;;aft~rgi,i~;yl the ;F: 1 / . 93155p15 1 Fig 29 Remove the fuel injectors from the
tall by gently rocking them loose Fig. 27 Remove the two fuel rail retaining
bolts . . .
93155ps Fig. 30 Always replace the O-rings on the
injectors before reinstalling them
1. Relieve the fuel system pressure as described
in this section.
2. Label and disconnect the spark plug wires. ’
Position the wires aside.
3. Disconnect the PCV hose from the valve
cover,
4. Remove the bolts holding the high pressure
fuel line to the fuel rail, then disconnect the line. Be
prepared to contain fuel spillage; plug the line to on the workbench; protect the tips of the injectors
from dirt and/or impact.
9. Remove and discard the injector insulators
from the intake manifold. The insulators are not
reusable.
10. Remove the injectors from
pulling gently in a straight outwarc the fuel rail by
I motion. Make cer-
tain the grommet and O-ring come off with the injector. 18. Connect the fuel return hose to the pressure
regulator, then connect the vacuum hose.
19. Replace the O-ring on the high pressure fuel
line, coat the O-ring lightly with clean, thin oil and
install the line to the fuel rail. Tiahten the mountina
To install: -
the fuel system and inspect all connections for leaks. bolts to 4 ft. Ibs. (6 Nm).
20. Connect the PCV hose and spark plug wires.
21. Connect the negative battery cable. Pressurize
1. neneve me rueI system pressure.
2. Disconnect the negative battery cable. 3.OL and 3.5L Engines
# See Figures 31 and 32
> - ,. .* , ,
I
I
Work MUST NOT be started until at least 90
seconds after the ignition switch is turned to
the LOCK position and the negative battery
cable is disconnected from the battery. This
will allow time for the air bag system backup
power supply to deplete its stored energy,
preventing accidental air bag deployment
which could result in unnecessary air bag
system repairs and/or personal injury.
3. Drain the cooling system.
4. Disconnect all components from the air in-
take plenum and remove the plenum from the intake
manifold. Refer to Section 3.
5. Wrap the connection with a shop towel and
disconnect the high pressure fuel line at the fuel rail. keep out dirt and debris.
Observe all applicable safety precautions
when working around fuel. Whenever servic-
ing the fuel system, always work in a well
ventilated area. Do not allow fuel spray or
vapors to come in contact with a spark or
open flame. Keep a dry chemical fire extin-
guisher near the work area. Always keep fuel
in a container specifically designed for fuel
storage; also, always properly seal fuel con-
tainers to avoid the possfbility of fire or ex-
plosion.
5. Remove the vacuum hose from the fuel pres-
sure regulator.
6. Disconnect the fuel return hose from the
pressure regulator.
7. Label and detach the electrical connectors
from each injector.
8. Remove the bolt(s) holding the fuel rail to the
manifold. Carefully lift the rail up and remove it with
the injectors attached. Take great care not to drop an
injector. Place the rail and injectors in a safe location 11. Install a new insulator in each injector port in
the manifold.
12. Remove the old grommet and D-ring from
each injector. Install a new grommet and O-ring; coat
the O-ring lightly with clean, thin oil.
13. If the fuel pressure regulator was removed, re-
place the O-ring with a new one and coat it lightly with
clean, thin oil. Insert the regulator straight into the rail,
then check that it can be rotated freely. If it does not ro-
tate smoothly, remove it and inspect the O-ring for de-
formation or jamming. When properly installed, align
the mounting holes and tighten the retaining bolts to 7
ft. Ibs. (9 Nm). This procedure must be followed even if
the fuel rail was not removed.
14. Install the injector into the fuel rail, constantly
turning the injector left and right during installation.
When fully installed, the injector should still turn
freely in the rail. If it does not, remove the injector
and inspect the O-ring for deformation or damage.
15. Install the delivery pipe and injectors to the
engine. Make certain that each injector fits correctly
into its port and that the rubber insulators for the fuel
rail mounts are in position.
16. Install the fuel rail retaining bolts and tighten
them to 9 ff. Ibs. (12 Nm).
17. Connect the wiring harnesses to the appro-
priate injector.

5-8 FUELSYSTEM
9 ,npimr w1m.m
1: i”“L,
1: 82”w
93155gx Fig. 31 Exploded view of the fuel injectors and related components-
s.OL engines
Observe all applicable safety precautions
when working around fuel. Whenever servic-
ing the fuel system, always work in a well
ventilated area. Do not allow fuel spray or
vapors to come in contact with a spark or
open flame. Keep a dry chemical fire extin-
guisher near the work area. Always keep fuel
in a container specifically designed for fuel
storage; also, always properly seal fuel con-
tainers to avoid the possibility of fire or ex-
plosion.
6. Disconnect the fuel return hose and remove
the O-ring.
7. Disconnect the vacuum hose from the fuel
pressure regulator.
8. Detach the electrical connectors from each
injector.
9. Remove the fuel pipe connectmg the fuel
rails. Remove the injector rail retaining bolts. Make
sure the rubber mounting bushings do not get lost.
10. Lift the rail assemblies up and away from the
engine.
11. Remove the injectors from the rail by pulling
gently. Discard the lower insulator.
To install:
*Some of the vehicles may have a clip that
secures the injector to the fuel rail. Be sure
to remove or install the injector clip where
necessary.
12. Install a new grommet and O-ring to the in-
jector. Coat the O-ring with light oil.
13. Install the injector to the fuel rail.
14. Replace the seats in the intake manifold. In-
stall the fuel rails and injectors to the manifold. Make
sure the rubber bushings are in place before tighten-
ing the mounting bolts.
15. Tighten the retaining bolts to 7-9 ft. Ibs.
(W-13 Nm) Install the fuel pipe with new gasket.
16. Attach the electrical connectors to the injec-
tors
Fig. 32 Exploded view of the fuel injectors and related components-
3.5L engine
17. Connect the fuel return hose.
18. Replace the O-ring, lightly lubricate it and
connect the high pressure fuel line.
19. Usmg new gaskets, install the intake plenum
and all related items. Refer to Section 3.
20. Fill the cooling system.
21. Connect the negative battery cable and check
the entire system for proper operation and leaks.
The easiest way to test the operation of the fuel in-
jectors is to listen for a clicking sound coming from
the injectors while the engine IS running. This is ac-
complished using a mechanic’s stethoscope, or a
long screwdriver. Place the end of the stethoscope or
the screwdriver (tip end, not handle) onto the body of
the injector. Place the ear pieces of the stethoscope
in your ears, or if using a screwdriver, place your ear
on top of the handle. An audible chcking noise
should be heard; this is the solenoid operating. If the
injector makes this noise, the injector driver circuit
and computer are operating as designed. Continue
testing all the injectors this way.
Be extremely careful while working on an op-
erating engine, make sure you have no dan-
gling jewelry, extremely loose clothes,
power tool cords or other items that might
get caught in a moving part of the ermine.
All Injectors Clicking
If all the injectors are clicking, but you have de-
termined that the fuel system is the cause of your
driveability problem, continue diagnostics. Make
sure that you have checked fuel pump pressure as
outlined earlier in this section. An easy way to de-
termine a weak or unproductive cylinder is a cylin-
der drop test. This is accomplished by removing
one spark plug wire at a time, and seeing which cylinder causes the least difference in the idle.
The one that causes the least change is the weak
cylinder.
If the injectors were all clicking and the ignition
system is functioning properly, remove the injector of
the suspect cylinder and bench test it. This is accom-
plished by checking for a spray pattern from the in-
jector itself Install a fuel supply line to the injector
(or rail if the injector is left attached to the rail) and
momentarily apply 12 volts DC and a ground to the
injector itself; a visible fuel spray should appear. If no
spray is achieved, replace the injector and check the
running condition of the engine.
One or More Injectors Are Not Clicking
6 See Figures 33, 34, 35, and 36
If one or more injectors are found to be not operat-
ing, testing the injector driver circuit and computer
can be accomplished using a “noid” light. First, with
the engine not running and the ignition key in the
OFF position, remove the connector from the injector
you plan to test, then plug the “noid” light tool into
the injector connector. Start the engine and the
“noid” light should flash, signaling that the injector
driver circuit is working. If the “noid” light flashes,
but the injector does not click when plugged in, test
the injectors resistance. Resistance should be be-
tween:
l All non-turbo engines: 13-16 ohms at 68°F
(20°C)
l Turbocharged engines: 2-3 ohms at 68 “F
(20°C)
If the “noid” light does not flash, the injector dri-
ver circuit is faulty. Disconnect the negative battery
cable. Unplug the “noid” light from the injector con-
nector and also unplug the PCM. Check the harness
between the appropriate pins on the harness side of
the PCM connector and the injector connector. Re-
sistance should be less than 5.0 ohms; if not, repair
the circuit. If resistance
IS within specifications, the
injector driver inside the PCM is faulty and replace-
ment of the PCM will be necessary.