check engine MITSUBISHI DIAMANTE 1900 Repair Manual

SUSPENSION AND STEERING 8-33
*Matchmark the pinion input shaft of the
rack to the lower steering column joint for in-
stallation purposes.
6. Remove the pinch bolt holding the lower
steering column joint to the rack and pinion input
shaft.
7. Remove the cotter pins and disconnect the tie
rod ends from the steering knuckle.
8. Remove the rack and pinion steering assem-
bly and its rubber mounts from the right side of the
vehicle.
To install: 9. Align the matchmarks of the input shaft and
install the rack to the vehicle.
10. Secure the rack using the retainer clamps and
bolts. Tighten the bolts to 51 ft. Ibs. (70 Nm).
11. Tighten the steering column pinch bolt to 13
ft. Ibs. (18 Nm).
12. Install the center member.
13. Install the front exhaust pipe.
14. Connect the HO$ sensor.
15. Connect the tie rod ends to the steering
knuckles and tighten the castle nuts to 25 ft. Ibs. (34
Nm). Install new cotter pins.
16. Install the wheels and connect the negative
battery cable.
17. Have a front end alignment performed.
REMOVAL &INSTALLATION
Diamante
FRONT
*Prior to removal of the steering gear box,
center the front wheels and remove the igni-
tion key. Failure to do so may damage the
SRS clock spring and render SRS system in-
operative.
1. Disconnect the negative battery cable.
2. Disconnect the front exhaust pipe.
3. If equipped with AWD, remove the transfer
case assembly.
4. Remove the bolt holding the lower steering
column joint to the rack and pinion input shaft.
5. Remove the cotter pins and disconnect the tie
rod ends.
6. Remove the left and right frame members.
7. Remove the stabilizer bar bracket.
8. If equipped with four-wheel steering, discon-
nect the lines going to the rear pump.
9. Remove the rack and pinion steering assem-
bly and its rubber mounts. Move the rack to the right
to remove it from the crossmember.
To install: IO. Install the rack and mounting bolts. Tighten
the bolts to 51 ft. Ibs. (70 Nm). When installing the
rubber rack mounts, align the projection of the
mounting rubber with the indentation in the cross:
member. Install the pinch bolt.
11. Connect the pressure and return lines to the
rack and to the rear pump, if equipped.
12. Install the frame members and tighten the
bolts to 43-51 ft. Ibs. (60-70 Nm).
13. Connect the tie rods and install new cotter
pins. 14. Install the transfer case and front exhaust
pipe.
15. Refill the reservoir and bleed the system.
16. Have a front end alignment performed.
REAR
1. Disconnect the negative battery cable.
2. Raise the vehicle and support safely.
3. Drain the power steering fluid.
4. Remove the main muffler assembly.
5. Remove the rear shock absorber lower
mounting bolts.
6. Using the proper equipment, support the
weight of the rear differential. Remove the 2 small
crossmember brackets.
7. Remove the large self-locking crossmember
mounting nuts on the differential side.
8. Remove the oil line clamp bolts.
9. Remove the pressure tubes.
IO. Hold the tie rod ends stationary and remove
the tie rod end nuts. Remove the tie rod ends from
the trailing arms.
11. Remove the mounting bolts and remove the
rear steering gear.
To install: 12. Secure the unit to the crossmember. Move
the power cylinder piston rod over its full stroke to
determine its neutral position.
13. Align the tie rod ends with the holes in the
trailing arms and install the nuts. Adjust the length of
the tie rods with the nuts if necessary. The difference
in length between the 2 tie rod ends should not ex-
ceed 0.04 in. (1 mm). The nuts’ torque specification is
42 ft. Ibs. (58 Nm).
14. Replace the O-rings and install the pressure
tubes. Clamp in place.
15. Install the large self-locking crossmember
mounting nuts on the differential side. Tighten to
80-94 ft. Ibs. (110-130 Nm).
16. Remove the support equipment.
17. Install the 2 small crossmember brackets.
18. Install the shock mounting bolts.
19. Install the muffler assembly.
20. Refill the reservoir and bleed the system.
21. Have a front end alignment performed. _
Galant
1990-93 MODELS
1. Disconnect the negative battery cable.
2. Drain the power steering fluid.
3. Raise the vehicle and support safely.
4. Remove the bolt holding lower steering col-
umn joint to the rack and pinion input shaft.
5. Remove the transfer case, if equipped.
6. Remove the cotter pins and using the proper
tools, separate the tie rod ends from the steering
knuckle.
7. Locate the triangular brace near the stabilizer
bar brackets on the crossmember and remove both
the brace and the stabilizer bar bracket.
8. Support the center crossmember.
9. Remove the through-bolt from the round roll
stopper and remove the rear bolts from the center
crossmember.
10. Disconnect the front exhaust pipe, if
equipped with FWD.
11. Disconnect the power steering fluid pressure
pipe and return hose from the rack fittings. Plug the
fittings to prevent excess fluid leakage. 12. Lower the crossmember slightly.
13. Remove the rack and pinion steering assem-
bly and its rubber mounts. Move the rack to the right
to remove from the crossmember. Tilt the assembly
downward and remove from the left side of the vehi-
cle. Use caution to avoid damaging the boots.
To install: 14. Install the rack and install the mounting bolts. Tighten the mounting bolts to 43-58 ft. Ibs. (60-80
Nm). When installing the rubber rack mounts, align
the projection of the mounting rubber with the inden-
tation in the crossmember.
15. Connect the power steering fluid lines to the
rack.
16. Connect the exhaust pipe, if removed.
17. Raise the crossmember into position. Install
the center member mounting bolts and tighten to 72
ft. Ibs. (100 Nm). Install the roll stopper bolt and new
nut. Tighten nut to 47 ft. Ibs. (65 Nm).
18. Install the stabilizer bar brackets and brace.
19. Connect the tie rod ends and tighten nuts to
25 ft. Ibs. (34 Nm).
20. Install the transfer case, if removed. Check
and fill fluid.
21. Refill the reservoir with power steering fluid
and bleed the system.
22. Have a front end alignment performed.
1994-M MODELS
+ See Figure 96
Prior to removal of the steering gear box,
center the front wheels and remove the igni-
tion key. Failure to do so may damage the
SRS clock spring and render SRS system in-
operative.
1. Disconnect the negative battery cable.
2. Raise and properly support the vehicle.
3. Remove both front wheel assemblies.
4. Remove the bolt holding lower steering col-
umn joint to the rack and pinion input shaft.
5. Remove the stabilizer bar.
6. Remove the cotter pins, and using joint sepa-
rator MB991 113 or equivalent, disconnect the tie rod
ends from the steering knuckle.
7. On vehicles equipped with Electronic Control
Power steering (EPS), detach the wiring harness from
the solenoid connector.
8. Locate the two triangular braces near the
crossmember and remove both.
9. Support the center crossmember. Remove the
through-bolt from the front round roll stopper and re-
move the bolts securing the center crossmember.
10. Remove the center crossmember. ,
Il. Properly support the engine and remove the
rear roll stopper through-bolt.
12. Disconnect the power steering fluid pressure
pipe and return hose from the rack fittings. Plug the
fittings to prevent excessive fluid leakage.
13. Remove the clamp bolts and the two bolts se-
curing the rack assembly to the chassis.
14. Remove the rack and pinion steering assem-
bly and its rubber mounts.
*When removing the rack and pinion as-
sembly, tilt the assembly to the vehicle side
of the compression lower arm and remove
from the left side of the vehicle.

9-2 BRAKES
Hydraulic systems are used to actuate the brakes
of all modern automobiles. The system transports the
power required to force the frictional surfaces of the
braking system together from the pedal to the indi-
vidual brake units at each wheel. A hydraulic system
is used for two reasons.
First, fluid under pressure can be carried to all
parts of an automobile by small pipes and flexible
hoses without taking up a significant amount of room
or posing routing problems.
Second, a great mechanical advantage can be
given to the brake pedal end of the system, and the
foot pressure required to actuate the brakes can be
reduced by making the surface area of the master
cylinder pistons smaller than that of any of the pis-
tons in the wheel cylinders or calipers.
The master cylinder consists of a fluid reservoir
along with a double cylinder and piston assembly.
Double type master cylinders are designed to sepa-
rate the front and rear braking systems hydraulically
in case of a leak. The master cylinder converts me-
chanical motion from the pedal into hydraulic pres-
sure within the lines. This pressure is translated back
into mechanical motion at the wheels by either the
wheel cylinder (drum brakes) or the caliper (disc
brakes).
Steel lines carry the brake fluid to a point on the
vehicle’s frame near each of the vehicle’s wheels. The
fluid is then carried to the calipers and wheel cylin-
ders by flexible tubes in order to allow for suspen-
sion and steering movements.
In drum brake systems, each wheel cylinder con-
tains two pistons, one at either end, which push out-
ward in opposite directions and force the brake shoe
into contact with the drum.
In disc brake systems, the cylinders are part of the
calipers. At least one cylinder in each caliper is used
to force the brake pads against the disc.
All pistons employ some type of seal, usually
made of rubber, to minimize fluid leakage. A rubber
dust boot seals the outer end of the cylinder against
dust and dirt. The boot fits around the outer end of
the piston on disc brake calipers, and around the
brake actuating rod on wheel cylinders.
The hydraulic system operates as follows: When at
rest, the entire system, from the piston(s) in the mas-
ter cylinder to those in the wheel cylinders or
calipers, is full of brake fluid. Upon application of the
brake pedal, fluid trapped in front of the master cylin-
der piston(s) is forced through the lines to the wheel
cylinders. Here, it forces the pistons outward, in the
case of drum brakes, and inward toward the disc, in
the case of disc brakes. The motion of the pistons is
opposed by return springs mounted outside the
cylinders in drum brakes, and by spring seals, in disc
brakes.
Upon release of the brake pedal, a spring located
inside the master cylinder immediately returns the
master cylinder pistons to the normal position. The
pistons contain check valves and the master cylinder
I
has compensating ports drilled in it. These are un-
covered as the pistons reach their normal position.
The piston check valves allow fluid to flow toward the
wheel cylinders or calipers as the pistons withdraw.
Then, as the return springs force the brake pads or
shoes into the released position, the excess fluid
reservoir through the compensating ports. It is during the time the pedal is in the released position that any
fluid that has leaked out of the system will be re-
placed through the compensating ports.
Dual circuit master cylinders employ two pistons,
located one behind the other, in the same cylinder.
The primary piston is actuated directly by mechanical
linkage from the brake pedal through the power
booster. The secondary piston is actuated by fluid
trapped between the two pistons. If a leak develops in
front of the secondary piston, it moves forward until it
bottoms against the front of the master cylinder, and
the fluid trapped between the pistons will operate the
rear brakes. If the rear brakes develop a leak, the pri-
mary piston will move forward until direct contact
with the secondary piston takes place, and it will
force the secondary piston to actuate the front brakes.
In either case, the brake pedal moves farther when the
brakes are applied, and less braking power is avail-
able.
All dual circuit systems use a switch to warn the
driver when only half of the brake system is opera-
tional. This switch is usually located in a valve body
which is mounted on the firewall or the frame below
the master cylinder. A hydraulic piston receives pres-
sure from both circuits, each circuits pressure being
applied to one end of the piston. When the pressures
are in balance, the piston remains stationary. When
one circuit has a leak, however, the greater pressure
in that circuit during application of the brakes will
push the piston to one side, closing the switch and
activating the brake warning light.
In disc brake systems, this valve body also con-
tains a metering valve and, in some cases, a propor-
tioning valve. The metering valve keeps pressure
from traveling to the disc brakes on the front wheels
until the brake shoes on the rear wheels have con-
tacted the drums, ensuring that the front brakes will
never be used alone. The proportioning valve con-
trols the pressure to the rear brakes to lessen the
chance of rear wheel lock-up during very hard brak-
ing.
Warning lights may be tested by depressing the
brake pedal and holding it while opening one of the
wheel cylinder bleeder screws. If this does not cause
the light to go on, substitute a new lamp, make conti-
nuity checks, and, finally, replace the switch as nec-
essary.
The hydraulic system may
be checked for leaks by applying pressure to the pedal gradually and steadily.
If the pedal sinks very slowly to the floor, the system
has a leak. This is not to be confused with a springy
or spongy feel due to the compression of air within
the lines. If the system leaks, there will be a gradual
change in the position of the pedal with a constant
pressure.
Check for leaks along all lines and at wheel cylin-
ders. If no external leaks are apparent, the problem is
inside the master cylinder,
DISC BRAKES
Instead of the traditional expanding brakes that
press outward against a circular drum, disc brake
systems utilize a disc (rotor) with brake pads posi-
tioned on either side of it. An easily-seen analogy is
the hand brake arrangement on a bicycle. The pads
squeeze onto the rim of the bike wheel, slowing its
motion. Automobile disc brakes use the identical principle but apply the braking effort to a separate
disc instead of the wheel.
The disc (rotor) is a casting, usually equipped with
cooling fins between the two braking surfaces. This
enables air to circulate between the braking surfaces
making them less sensitive to heat buildup and more
resistant to fade. Dirt and water do not drastically af-
fect braking action since contaminants are thrown off
by the centrifugal action of the rotor or scraped off
the by the pads. Also, the equal clamping action of
the two brake pads tends to ensure uniform, straight
line stops. Disc brakes are inherently self-adjusting.
There are three general types of disc brake:
1. A fixed caliper.
2. A floating caliper.
3. A sliding caliper.
The fixed caliper design uses two pistons
mounted on either side of the rotor (in each side of
the caliper). The caliper is mounted rigidly and does
not move.
The sliding and floating designs are quite similar.
In fact, these two types are often lumped together. In
both designs, the pad on the inside of the rotor is
moved into contact with the rotor by hydraulic force.
The caliper, which is not held in a fixed position,
moves slightly, bringing the outside pad into contact
with the rotor. There are various methods of attaching
floating calipers. Some pivot at the bottom or top,
and some slide on mounting bolts. In any event, the
end result is the same.
DRUM BRAKES
Drum brakes employ two brake shoes mounted on
a stationary backing plate. These shoes are posi-
tioned inside a circular drum which rotates with the
wheel assembly. The shoes are held in place by
springs. This allows them to slide toward the drums
(when they are applied) while keeping the linings and
drums in alignment. The shoes are actuated by a
wheel cylinder which is mounted at the top of the
backing plate. When the brakes are applied, hydraulic
pressure forces the wheel cylinder’s actuating links
outward. Since these links bear directly against the
top of the brake shoes, the tops of the shoes are then
forced against the inner side of the drum. This action
forces the bottoms of the two shoes to contact the
brake drum by rotating the entire assembly slightly
(known as servo action). When pressure within the
wheel cylinder is relaxed, return springs pull the
shoes back away from the drum.
Most modern drum brakes are designed to self-
adjust themselves during application when the vehi-
cle is moving in reverse. This motion causes both
shoes to rotate very slightly with the drum, rocking
an adjusting lever, thereby causing rotation of the ad-
justing screw. Some drum brake systems are de-
signed to self-adjust during application whenever the
brakes are applied. This on-board adjustment system
reduces the need for maintenance adjustments and
keeps both the brake function and pedal feel satisfac-
tory.
POWER BOOSTERS
Virtually all modern vehicles use a vacuum as-
sisted power brake system to multiply the braking
force and reduce pedal effort. Since vacuum is always
available when the engine is operating, the system is

BRAKiS 9-3
simple and efficient. A vacuum diaphragm is located gine. Have an assistant observe the brake lights at the
on the front of the master cylinder and assists the dri- rear of the vehicle while you push on the brake pedal.
ver in applying the brakes, reducing both the effort The lights should come on just as the brake pedal
and travel he must put into moving the brake pedal. passes the point of free play.
The vacuum diaphragm housing is normally con- 9.
Adjust the brake light switch as necessary. The
netted to the intake manifold by a vacuum hose. A small amount of free play in the
pedal should not
check valve is placed at the point where the hose en-
ters the diaphragm housing, so that during periods
Of low manifold vacuum brakes assist will not be lost.
Depressing the brake pedal closes off the vacuum
source and allows atmospheric pressure to enter on
one side of the diaphragm. This causes the master
cylinder pistons to move and apply the brakes. When
the brake pedal is released, vacuum is applied to
REMOVAL &INSTALLATION
both sides of the diaphragm and springs return the
diaphragm and master cylinder pistons to the re- ) See Figures 2 thru 10
leased position.
If the vacuum supply fails, the brake pedal rod will
contact the end of the master cylinder actuator rod
and the system will apply the brakes without any
power assistance. The driver will notice that much
higher pedal effort is needed to stop the car and that
the pedal feels harder than usual.
Vacuum leak Test
1. Operate the engine at idle without touching the
brake pedal for at least one minute.
2. Turn off the engine and wait one minute.
3. Test for the presence of assist vacuum by de-
pressing the brake pedal and releasing it several
3 MASTER N- 188A11Ly
times. If vacuum is present in the system, light appli- . KLNsIMEm 0s CLWRANCE
BETWEEN BRAKE WOSTER
cation will produce less and less pedal travel. If there PUSHROO AN0 PRIMARY PISTCU
is no vacuum, air is leaking into the system.
System Operation Test
1. With the engine OFF, pump the brake pedal
until the supply vacuum is entirely gone.
2. Put light, steady pressure on the brake pedal.
3. Start the engine and let it idle. If the system is
operating correctly, the brake pedal should fall to-
ward the floor if the constant pressure is maintained.
Power brake systems may be tested for hydraulic
leaks just as ordinary systems are tested.
REMOVAL&INSTALLATION
$ See Figure 1
1. Disconnect the negative battery cable.
2. Detach the stop lamp switch electrical harness
connector.
3. Loosenthe locknut holding the switch to the
bracket. Remove the locknut and the switch.
To install:
4.
Install the new switch and install the locknut,
tightening it just snug.
5. Reposition the brake light switch so that the
distance between the outer case of the switch and the
pedal is 0.02-0.04 in. (0.5-l .Omm). Note that the
switch plunger must press against the pedal to keep
the brake lights off. As the pedal moves away from
the switch, the plunger extends and closes the
switch, which turns on the stop lights.
6.
Hold the switch in the correct position and
tighten the locknut.
7. Connect the wiring to the switch.
8. Check the operation of the switch. Turn the ig-
nition key to the ON position but do not start the en-

9-4 BRAKES
Fig 8 Unfasten the master cylinder-to-
power booster retaining nuts . . . F57g’6~ Fig. 9 . . . then remove the master cylinder
assembly from the vehicle Fig. 10 The brake booster pushrod and prf-
mary piston clearance (A) must be adjusted
1. Disconnect the negative battery cable.
2. Remove the master cylinder reservoir cap,
then use a clean turkey baster or equivalent to siphon
out as much fluid as possible and place in a suitable
container. Install the cap.
Brake fluid contains polyglycol ethers and
polyglycols. Avoid contact with the eyes and
wash your hands thoroughly after handling
brake fluid. If you do get brake fluid in your
eyes, flush your eyes with clean, running wa-
ter for 15 minutes. If eye irritation persists,
or if you have taken brake fluid internally,
IMMEDIATELY seek medical assistance.
3. Disconnect and plug the lines from the brake
master cylinder reservoir.
4. Detach the fluid level sensor connector, un-
fasten the retainers, then remove the master cylinder
reservoir.
5. For vehicles equipped with manual transaxle,
remove the clutch master cylinder reservoir bracket.
6. Disconnect and plug the brake lines from the
master cylinder.
7. Unfasten the master cylinder-to-power
booster retainino nuts, then remove the master cvlin- ante value will become 0.004-0.012 in.
(0.1-0.3mm).
9. install the master cylinder to the brake
booster, then install the retaining nuts. Tighten the
nuts to 7 ft. Ibs. (10 Nm).
10. Install the master cylinder reservoir, securing
the retainers.
11. Attach the fluid level sensor connector, then
unplug and connect the fluid lines to the reservoir.
12. The remainder of installation is the reverse of
the removal procedure. Fill the reservoir with the
proper type and amount of DOT 3 brake fluid from a
fresh, sealed container.
I l
Clean, high quality brake fluid is essential to
the safe and proper operation of the brake
system. You should always buy the highest
quality brake fluid that is available. If the
brake fluid becomes contaminated, drain and
flush the system, then refill the master cylin-
der with new fluid. Never reuse any brake
fluid. Any brake fluid that is removed from
the system should be discarded. Also, do not
allow any brake fluid to come in contact with
a painted surface; it will damage the paint. Measure the brake pedal height from the floor of
the vehicle to the upper surface of the brake pedal.
The distance should be 6.9-7.1 in (176181mm). If
the brake pedal height is incorrect, adjust as follows:
1. Detach the stop lamp switch connector.
2. Loosen the locknut on the base of the stop
light switch and move the switch to a position where
it does not contact the brake pedal.
3. Loosen the operating rod locknut. Adjust the
height of the brake pedal by turning the operating rod
using pliers. Once the desired pedal height is ob-
tained, tighten the locknut on the operating rod.
4. Screw the stop light switch until the it contacts
the brake pedal stopper. Turn switch in until the
brake pedal just starts to move. At this point, return
(loosen) the stoplight switch $-1 turn and secure in
this position by tightening the locknut. In this posi-
tion, the distance between the lower stop light switch
case and the brake pedal stop should be 0.02-0.04
in. (0.5-l .Omm).
5. Attach the electrical connector to the stop light
switch.
6. Check to be sure that the stop lights are not il-
luminated with no pressure on the brake pedal.
7. Without starting the vehicle, depress the brake
pedal. If the brake light switch is properly connected,
the brake lights will illuminate.
der from the vefiicle.
To install:
8. Adjust the clearance (A)
booster pushrod ant
a. Calculate tl -,
between the brake
I the primary piston as follows:
le clearance A from the B, C
accompa-
i D.
I.335 in.
negative and D measurements, as shown in the
nying figure.A equals B minus C minus
b. The clearance should be 0.256-t
(0.65-0.858mm). When brake booster I
pressure 9.7 psi (67 kPa) is applied, then clear- 13. Bleed the brake system, as outlined later in
this section.
14. Adjust the brake pedal, as outlined later in
this section.
BRAKE PEDAL ADJUSTMENTS
Brake Pedal Height
b See Figures 11, 12, and 13 Brake Pedal Free-Play
II See Figure 14
1. With the engine off, depress the brake pedal
fully several times to evacuate the vacuum in the
booster.
2. Once all the vacuum assist has been elimi-
nated, press the brake pedal down by hand and con-
/
0.5-1.0 mm (.020-B40in.J I
I
I I
Fig. 12 Adjust the brake pedal height by in- I I.
@57w
Cir 44 “a*., .._^ *I.- 9.--l,- ---I-* L-@-L. -I Fig. 13 Inspect the clearance between thf . . - _-.L -*.a- - . . * _ . . . . ._ . rly. I I rnca~urc we urime peoai nefgnr ar
A and compare to specifications creasmg or aecreasing the lengrn or me op-
erating rod mop llgnt WItCh arm the brake pedal stop
and compare to specifications

BRAKES 9-5
Inspect brake pedal free-play
firm that the amount of movement before resistance
is felt is within 0.1-0.3 in. (3-8mm).
3. If the free-play is less than desired, confirm
that the brake light switch is in proper adjustment.
4. If there is excessive free-play, look for wear or
play in the clevis pin and brake pedal arm. Replace
worn parts as required and recheck brake pedal free-
Play*
REMOVAL &INSTALLATION '
b See Figure 15
1. Disconnect the negative battery cable.
2. Siphon the brake fluid from the master cylin-
der reservoir.
Brake fluid contains polyglycol ethers and
polyglycols. Avoid contact with the eyes and
wash your hands thoroughly after handling
brake fluid. If you do get brake fluid in your
eyes, flush your eyes with clean, running wa-
. ter for 15 minutes. If eye irritation persists,
or if you have taken brake fluid internally,
IMMEDIATELY seek medical assistance.
3. Remove and relocate the air conditioning re-
lay box and the solenoid valve located at the power
brake unit.
4. Disconnect the vacuum hose from the
booster by pulling it straight off. Prying off the vac-
uum hose could damage the check valve installed in
the brake booster vacuum hose.
5. Detach the electrical harness connector from
the brake level sensor.
6. Remove the nuts attaching the master cylin-
der to the booster and remove the master cylinder
and position aside. If necessary, disconnect and plug
the brake fluid lines at the master cylinder.
7. From inside the passenger compartment, re-
move the cotter pin and clevis pin that secures the
booster pushrod to the brake pedal.
8. From inside the vehicle, remove the nuts that
attach the booster to the dash panel. Remove the
brake booster from the engine compartment.
To install: 9. Install the brake booster to the dash panel.
From inside the vehicle, install the attaching nuts and
tighten to 12 ft. Ibs. (17 Nm). 10. Apply grease to the clevis pin and install with
washers in place. Install new cotter pin and bend to
secure in place.
11. Attach the vacuum hose to the booster fitting.
12. Install the master cylinder assembly to the
mounting studs on the brake booster. Install the mas-
ter cylinder mounting nuts and tighten to 9 ft. Ibs. (12
Nm).
13. Reconnect the brake fluid reservoir to the
master cylinder, if disconnected. Attach the electrical
connector to the brake fluid level sensor.
14. Install the solenoid valve assembly and the
relay box, if removed.
15. Connect the negative battery cable.
16. Add fluid to the brake fluid reservoir as re-
quired.
Clean, high quality brake fluid is essentlal to
the safe and proper operation of the brake
system. You should always buy the highest
quality brake fluid that is available. If the
brake fluid becomes contaminated, drain and
flush the system, then refill the master cylin-
der with new fluid. Never reuse any brake
fluid. Any brake fluid that is removed from
the system should be discarded. Also, do not
allow any brake fluid to come in contact with
a painted surface; it will damage the paint.
17. Bleed the master cylinder. If after bleeding the
master cylinder the brake pedal feels soft, bleed the
brake system at all wheels.
18. Check the brake system for proper operation. *
rn( mr
'13 1. Relay box for air
conditioner
l-13 t- I, Ltx5. 5-18 NM 2. Solenoid valve
3. Brake fluid level
sensor connector
6 4. Brake tube
5. Master cylinder, hose
and reservoir
assem biy
Fig. 15 Exploded view of the power brake booster and related components-most models
12.
13.
14. Fitting 1
Cotter pin;
Washer 1
Clevis pin’ Fuel retuti tub8 installatiob bolt
Brake tUd8 installatioh bolt
Brake booster
Sealer
89579glt

BRAKES 9-23
1. Make sure the parking brake cable is free and
is not frozen or sticking.
2. Apply the parking brake with 45 Ibs. (200 N) of
force while counting the number of notches. The de-
sired parking brake stroke should be 5-7 notches.
3. If adjustment is required, access the adjusting
nut from inside the floor console.
4. Loosen the locknut on the cable rod.
5. Rotate the adjusting nut to adjust the parking
brake stroke to the 5-7 notch setting. After making
the adjustment, check there is no looseness between
the adjusting nut and the parking brake lever, then
tighten the locknut.
*Do not adjust the parking brake too tight. If
the number of notches is less than specifica-
tion, the cable has been pulled too much and
the automatic adjuster will fail or the brakes
will drag.
6. After adjusting the lever stroke, raise the rear of
the vehicle and safely support. With the parking brake
lever in the released position, turn the rear wheels to
confirm that the rear brakes are not dragging.
7. Check that the parking brake holds the vehicle
on an incline.
Galant
‘ 1990-93 VEHICLES
# See Figure 111
1. Pull the parking brake lever up with a force of
about 45 Ibs. (200 N). The total number of clicks
heard should be 5-7 clicks. If the number of clicks
was not within that range, the system requires adjust-
ment.
*The parking brake shoes must be adjusted
before attempting to adjust the cable mecha-
nism
2. To adjust the parking brake shoes perform the
following steps.
a. Remove the floor console, release the lever
and back off the cable adjuster locknut at the
base of the lever.
b. Raise the vehicle, support safely and re-
move the wheel.
c. Remove the hole plug in the brake rotor.
d. Remove the brake caliper and hang out of
the way with wire. Do not disconnect the fluid
line.
e. Use a suitable prybar to pry up on the self-
adjuster wheel until the rotor will not turn.
f. Return the adjuster 5 notches in the oppo-
site direction. Make sure the rotor turns freely
with a slight drag.
Fig. 111 Parking brake system adjustment
points-1993 Galant
g. Install the caliper and check operation.
3. Once the parking brake shoes have been prop-
erly adjusted, adjust the cable mechanism, by per-
forming the following steps: _
a. Turn the adjusting nut to give the proper
number of clicks when the lever is raised full
travel.
b. Raise and support the rear of the car on
jackstands.
c. Release the brake lever and make sure that
the rear wheels turn freely. If not, back off on the
adjusting nut until they do.
1994470 VEHICLES
1, Pull the parking brake lever with a force of ap-
prox. 45 Ibs. (200 N) and count the number of
notches. Standard value is: 5-7 notches.
The 45 lbs. (200 N) force of the parking brake
lever must be strictly observed.
2. If the parking brake lever is not the standard
value, adjust in the following manner:
a. Remove the inner compartment mat of the
floor console
b. Loosen the adjusting nut at the end of the
cable rod, freeing the parking brake.
c. With the engine idling, forcefully depress
the brake pedal five or six times and confirm that
the pedal stroke stops changing. If the pedal
stroke stops changing, the automatic-adjustment
mechanism is functioning normally, and the
clearance between the shoe and the drum is cor-
rect.
d. After adjusting the parking brake lever
stroke, safely raise and support the rear of the
vehicle and with the parking brake lever in the re-
leased position, turn the rear wheels to confirm
that there is no brake drag.
Diamante
1. Pull the parking brake lever up with a force of
about 45 Ibs. (200 N). The total number of clicks
heard should be 3-5. If the number of clicks was not
within that range, the system requires adjustment.
93159901 Fig. 112 Exploded view of the parking shoes
and related components-1994-00 Galant
with disc brakes *The parking brake shoes must be adjusted
before attempting to adjust the cable mecha-
nism
2. To adjust the parking brake shoes, perform the
following steps: -
a. Remove the floor console, release the lever
and back off the cable adjuster locknut at the
base of the lever.
b. Raise the vehicle, support safely and re-
move the wheel. Remove the hole plug in the
brake rotor.
c. Remove the brake caliper and hang out of
the way with wire, Do not disconnect the fluid
line.
d. Use a suitable prybar to pry up on the self-
adjuster wheel until the rotor will not turn.
e. Return the adjuster 5 notches in the oppo-
site direction, Make sure the rotor turns freely
with a slight drag.
f. Install the caliper and check operation.
3. Once the parking brake shoes have been prop-
erly adjusted, adjust the cable mechanism, by per-
forming the following steps:
a. Pull the parking brake lever up with a force
of 45 Ibs. (200 N). The total number of clicks
heard should be 3-5.
b. Turn the adjusting
nut to give the proper
number of clicks when the lever is raised.
c. Raise and support the rear of the car on
jackstands.
d. Release the brake lever and make sure
that the rear wheels turn freely.
REMOVAL &INSTALLATION
1994-00 Galant and 1992-96 Diamante
# See Figures 112, 113, and 114
1. Raise and safely support the vehicle securely
on jackstands.
2. Remove the caliper assembly.
3. Remove the rear brake rotor.
I
I 93159902 Fig. 113 Exploded view of the parking brake
shoes and related components-1992-96
Diamante

BRAKES 9-25
Diagnostic inspection item Diagnostic content
trouble
code No.
11 Right front wheel speed sensor
12 Left front wheel speed sensor Open circuit
13 Right rear wheel speed sensor
14 Left rear wheel speed sensor
Abnormal output signal
Abnormal battery posi-
tive voltage 15 Wheel speed sensor system
16 Power supply system
r 21
I Right front wheel speed sensor 1 Excessive gap
22 I Left front wheel speed sensor or short circuit
23 Right rear wheel speed sensor
24 Left rear wheel speed sensor
36 Stop light switch system Open circuit or ON mal-
function
Right front solenoid valve system
I 5’ I Valve relay system 1 Valve relay OFF failure
I 53 1 Motor relay or motor system Motor relay OFF failure
and motor drive failure
63 ABS-ECU Malfunction in ABS-
ECU (program maze,
etc.)
I
!
Detection
conditions
B ’
A, B
A, B
A, B
A, 8
B
A, B
Detection conditions
A: During system check immediately after starting
B: When driving
89579954 Fig. 117 ABS diagnostic trouble code list-1992-96 Diamante
Diagnostrc
trouble Inspection item Detectron
code no. condalons
1
11 1 Front right wheel speed SensOr
I
I I
12 1 Front left wheel speed sensor
13 1 Rear right wheel speed sensor Open circuit
lBsC I
14
Rear left wheel speed sensor
15 Wheel speed sensor output signal abnormal
16 Power supply system
21 Front right wheel speed sensor A B
A, B, C
22 Front left wheel speed sensor
23 Rear right wheel speed sensor
24 Rear left wheel speed sensor
38 Stop light switch system Short circuit
8, c
B. C
41 1 Front right solenoid valve (inlet)
I I
42
Front left solenoid valve (inlet)
43 Rear right solenord valve (inlet) 0.c
44 Rear left solenoid valve (inlet)
45 Front right solenoid valve (outlet)
46 Front left solenoid valve (outlet)
47
Rear nght solenoid valve (outret) - B,C
48 Rear left solenoid valve (outlet)
51
Valve relay A 6, c
53
Motor relay B
63 ABSECU A B, c
Detection conditions
A: During system check immediately after starting 6: While ABS control is not operating while driving C: While ABS control is operating 93159go4 Fig. 118 ABS diagnostic trouble code list-1997-00 Diamante
The ABS control unit performs system tests and
self-tests during startup and normal operation. The
valves, wheel sensors and fluid level circuits are
monitored for proper operation. If a fault is found, the ABS will be deactivated and the amber ANTI LOCK
light will be lit until the ignition is turned OFF. When
the light is lit, the Diagnostic Trouble Code (DTC)
may be obtained. Under normal operation, the ANTI-
89579g53 Fig. 119 ABS diagnostic trouble code list-
1990-93 Galant
LOCK warning lamp will flash either twice (FWD) or 4
times (AWD) vehicles, in about 1 second with the ig-
,
nition switch ON , then the lamp will turn OFF.
The Diagnostic Trouble Codes (DTC) are an al-
phanumeric code and a scan tool, such as DRB-III,
MUT-II or equivalent diagnostic scan tool, is required
to retrieve the codes. Refer to the scan tool manufac-
turers instructions for operating the tool and retriev-
ing the codes.
The Data Link Connector (DLC) for the ABS is lo-
cated under the dash on the driver’s side. It is the
same connector used for the electronic engine con-
trol system.
REMOVALANDINSTALLATION
The Hydraulic Control Unit (HCU) is located in the
engine compartment. It contains the solenoid valves
and the pump/motor assembly which provides pres-
surized fluid for the anti-lock system when necessary.
Hydraulic units are not interchangeable on any vehi-
cles Neither unit is serviceable; if any fault occurs
within the hydraulic unit, the entire unit must be re-
placed.
Diamante
b See Figure 124
1. Disconnect the negative battery cable.
2. Remove the splash shield from beneath the
vehicle.
3. Use a syringe or similar device to remove as
much fluid as possible from the reservoir. Some fluid
will be spilled from lines during removal of the hy-
draulic unit; protect adjacent painted surfaces.
Brake fluid contains polyglycol ethers and
poly9lycols. Avoid contact with the eyes and
wash your hands thoroughly after handling
brake fluid. If you do 9et brake fluid in your
eyes, flush your eyes with clean, running wa-
ter for 15 minutes. If eye irritation persists,
or if you have taken brake fluid internally,
IMMEDIATELY seek medical assistance.
4. Lift the relay box with the harness attached
and position it aside.
5. Remove the air intake duct.
6. Disconnect the brake lines from the hydraulic
unit. Correct reassembly is critical. Label or identify
the lines before removal. Plug each line immediately

.
TROUBLESHOOTING II-5
Condition Section/Item Number
One brake light inoperative
Both brake lights inoperative
One or both brake lights very dim 5-D, 1
5-D, 2
5-D, 3
Ignition, Battery and Alternator Warning Lights, Check Engine
Light, Anti-Lock Braking System (ABS) Light, Brake Warning
Light, Oil Pressure Warning Light, and Parking Brake Warning
Light
Warning light(s) remains on after the engine is started
Warning light(s) flickers on and off when driving
Warning light(s) inoperative with ignition on, and engine not started 5-E, 1
5-E, 2
5-E, 3
Turn signals or hazard lights come on, but do not flash
Turn signals or hazard lights do not function on either side
Turn signals or hazard lights only work on one side
One signal light does not work
Turn signals flash too slowly
Turn signals flash too fast
Four-way hazard flasher indicator light inoperative
Turn signal indicator light(s) do not work in either direction
One turn signal indicator light does not work 5-F, 1
5-F, 2
5-F, 3
5-F, 4
5-F, 5
5-F, 6
5-F, 7
5-F, 8
5-F, 9
Horn does not operate
Horn has an unusual tone 5-G, 1
5-G, 2
Windshield wipers do not operate
Windshield wiper motor makes a humming noise, gets hot or blows fuses
Windshield wiper motor operates but one or both wipers fail to move
Windshield wipers will not park 5-H, 1
5-H, 2
5-H, 3
5-H, 4
Speedometer does not work
Speedometer needle fluctuates when driving at steady speeds
Speedometer works intermittently 6-A, 1
6-A, 2
6-A, 3
Speedometer does not work
Speedometer works intermittently 6-B, 1
6-B, 2
Gauge does not register 6-C 1
Gauge operates erratically 6-C 2
’
Gauge operates fully pegged 6-C 3
No air coming from air conditioner vents 7-A, 1
Air conditioner blows warm air ’ 7-A, 2
Water collects on the interior floor when the air conditioner is used
Air conditioner has a moldy odor when used 7-A, 3
7-A, 4
Blower motor does not operate
Heater blows cool air
Heater steams the windshield when used 7-B, 1
7-B, 2
7-B, 3

II-6 TROUBLESHOOTING
DIAGhUSTIC PROCEDURES
Gasoline Engines
1. Engine turns over, but wilt not start
a. Check fuel level in fuel tank, add fuel if empty.
b. Check battery condition and state of charge. If voltage and load test below specifica-
tion, charge or replace battery.
c. Check battery terminal and cable condition and tightness. Clean terminals and replace
damaged, worn or corroded cables.
d. Check fuel delivery system. If fuel is not reaching the fuel injectors, check for a loose
electrical connector or defective fuse, relay or fuel pump and replace as necessary.
e. Engine may have excessive wear or mechanical damage such as low cylinder cranking
pressure, a broken camshaft drive system, insufficient valve clearance or bent valves.
f. Check for fuel contamination such as water in the fuel. During winter months, the wa-
ter may freeze and cause a fuel restriction. Adding a fuel additive may help, however
the fuel system may require draining and purging with fresh fuel.
g. Check for ignition system failure. Check for loose or shorted wires or damaged igni-
tion system components. Check the spark plugs for excessive wear or incorrect elec-
trode gap. If the problem is worse in wet weather, check for shorts between the spark
plugs and the ignition coils.
h. Check the engine management system for a failed sensor or control module.
2. Engine does not turn over when attempting to start
a. Check the battery state of charge and condition. If the dash lights are not visible or
very dim when turning the ignition key on, the battery has either failed internally or
discharged, the battery cables are loose, excessively corroded or damaged, or the al-
ternator has failed or internally shorted, discharging the battery. Charge or replacethe
battery, clean or replace the battery cables, and check the alternator output.
b. Check the operation of the neutral safety switch. On automatic transmission vehicles,
try starting the vehicle in both Park and Neutral. On manual transmission vehicles, de-
press the clutch pedal and attempt to start. On some vehicles, these switches can be
adjusted. Make sure the switches or wire connectors are not loose or damaged. Re-
place or adjust the switches as necessary.
c. Check the starter motor, starter solenoid or relay, and starter motor cables and wires.
Check the ground from the engine to the chassis. Make sure the wires are not loose,
damaged, or corroded. If battery voltage is present at the starter relay, try using a re-
mote starter to start the vehicle for test purposes only. Replace any damaged or cor-
roded cables, in addition to replacing any failed components.
d. Check the engine for seizure. If the engine has not been started for a long period of
time, internal parts such as the rings may have rusted to the cylinder walls. The engine
may have suffered internal damage, or could be hydro-locked from ingesting water.
Remove the spark plugs and carefully attempt to rotate the engine using a suitable
breaker bar and socket on the crankshaft pulley. If the engine is resistant to moving, or
moves slightly and then binds, do not force the engine any further before determining
the problem.
3. Enpine stalls immediately when started
a. Check the ignition switch condition and operation. The electrical contacts in the run
position may be worn or damaged. Try restarting the engine with all electrical acces-
sories in the off position. Sometimes turning the key on an off will help in emergency
situations, however once the switch has shown signs of failure, it should be replaced
as soon as possible.
b. Check for loose, corroded, damaged or shorted wires for the ignition system and re-
pair or replace.
c. Check for manifold vacuum leaks or vacuum hose leakage and repair or replace parts
as necessary.
d. Measure the fuel pump delivery volume and pressure. Low fuel pump pressure can
also be noticed as a lack of power when accelerating. Make sure the fuel pump lines
are not restricted. The fuel pump output is not adjustable and requires fuel pump re-
placement to repair.
e. Check the engine fuel and ignition management system. Inspect the sensor wiring and
electrical connectors. A dirty, loose or damaged sensor or control module wire can
simulate a failed component.
f. Check the exhaust system for internal restrictions.
4. Starter motor spins, but does not engage
a. Check the starter motor for a seized or binding pinion gear.
b. Remove the flywheel inspection plate and check for a damaged ring gear.
5. Engine is difficult to start when Gold
a. Check the battery condition, battery state of charge and starter motor current draw. Re-
place the battery if marginal and the starter motor if the current draw is beyond specifi-
cation. b. Check the battery cable condition. Clean the battery terminals and replace corroded or
damaged cables.
c. Check the fuel system for proper operation. A fuel pump with insufficient fuel pressure
or clogged injectors should be replaced.
d. Check the engine’s tune-up status. Note the tune-up specifications and check for items
such as severely worn spark plugs; adjust or replace as needed. On vehicles with
manually adjusted valve clearances, check for tight valves and adjust to specification.
e. Check for a failed coolant temperature sensor, and replace if out of specification.
f. Check the operation of the engine management systems for fuel and ignition; repair or
replace failed components as necessary.
6. En#ine is ditticutt to start when hot
a. Check the air filter and air intake system. Replace the air filter if it is dirty or contami-
nated. Check the fresh air intake system for restrictions or blockage.
b. Check for loose or deteriorated engine grounds and clean, tighten or replace as
needed.
c. Check for needed maintenance. Inspect tune-up and service related items such as
spark plugs and engine oil condition, and check the operation of the engine fuel and
ignition management system.
Diesel Engines
1. Engine turns over but won’t start
a. Check engine starting procedure and restart engine.
b. Check the glow plug operation and repair or replace as necessary.
c. Check for air in the fuel system or fuel filter and bleed the air as necessary.
d. Check the fuel delivery system and repair or replace as necessary.
e. Check fuel level and add fuel as needed.
f. Check fuel quality. If the fuel is contaminated, drain and flush the fuel tank.
g. Check engine compression. If compression is below specification, the engine may
need to be renewed or replaced.
h. Check the injection pump timing and set to specification.
i. Check the injection pump condition and replace as necessary.
j. Check the fuel nozzle operation and condition or replace as necessary.
2. Engine does
hot turn over when attempting to start
a. Check the battery state of charge and condition. If the dash lights are not visible or
very dim when turning the ignition key on, the battery has either failed internally or
discharged, the battery cables are loose, excessively corroded or damaged, or the al-
ternator has failed or internally shorted, discharging the battery. Charge or replace the
battery, clean or replace the battery cables, and check the alternator output.
b. Check the operation of the neutral safety switch. On automatic transmission vehicles,
try starting the vehicle in both Park and Neutral. On manual transmission vehicles, de-
press the clutch pedal and attempt to start. On some vehicles, these switches can be
adjusted. Make sure the switches or wire connectors are not loose or damaged. Re-
place or adjust the switches as necessary.
c. Check the starter motor, starter solenoid or relay, and starter motor cables and wires.
Check the ground from the engine to the chassis. Make sure the wires are not loose,
damaged, or corroded. If battery voltage is present at the starter relay, try using a re-
mote starter to start the vehicle for test purposes only. Replace any damaged or cor-
roded cables, in addition to replacing any failed components.
d. Check the engine for seizure. If the engine has not been started for a long period of
time, internal parts such as the rings may have rusted to the cylinder walls. The engine
may have suffered internal damage, or could be hydro-locked from ingesting water.
Remove the injectors and carefully attempt to rotate the engine using a suitable
breaker bar and socket on the crankshaft pulley. If the engine is resistant to moving, or
moves slightly and then binds, do not force the engine any further before determining
the cause of the problem.
3. Engine stalls afier starting
a. Check for a restriction in the fuel return line or the return line check valve and repair as
necessary.
b. Check the glow plug operation for turning the glow plugs off too soon and repair as
necessary.
c. Check for incorrect injection pump timing and reset to specification.
d. Test the engine fuel pump and replace if the output is below specification.
e. Check for contaminated or incorrect fuel. Completely flush the fuel system and replace
with fresh fuel.
f. Test the engine’s compression for low compression. If below specification, mechanical
repairs are necessary to repair.
g. Check for air in the fuel. Check fuel tank fuel and fill as needed.
h. Check for a failed injection pump. Replace the pump, making sure to properly set the
pump timing.

TROUBLESHOOiNG 11-7
4. Starter motor spins, but does not engage
a. Check the starter motor for a seized or binding pinion gear.
b. Remove the flywheel inspection plate and check for a damaged ring gear.
Gasoline Engines
1. Engine runs poor/y, hesiiates
a. Check the engine ignition system operation and adjust if possible, or replace defective
parts.
b. Check for restricted fuel injectors and replace as necessary.
c. Check the fuel pump output and delivery. Inspect fuel lines for restrictions. If the fuel
pump pressure is below specification, replace the fuel pump.
d. Check the operation of the engine management system and repair as necessary.
2. Enfline lacks power
a. Check the engine’s tune-up status. Note the tune-up specifications and check for items
such as severely worn spark plugs; adjust or replace as needed. On vehicles with
manually adjusted valve clearances, check for tight valves and adjust to specification.
b. Check the air filter and air intake system. Replace the air filter if it is dirty or contami-
nated. Check the fresh air intake system for restrictions or blockage.
c. Check the operation of the engine fuel and ignition management systems. Check the
sensor operation and wiring. Check for low fuel pump pressure and repair or replace
components as necessary.
d. Check the throttle linkage adjustments. Check to make sure the linkage is fully open-
ing the throttle. Replace any worn or defective bushings or linkages.
e. Check for a restricted exhaust system. Check for bent or crimped exhaust pipes, or in-
ternally restricted mufflers or catalytic converters. Compare inlet and outlet tempera-
tures for the converter or muffler. If the inlet is hot, but outlet cold, the component is
restricted.
f. Check for a loose or defective knock sensor. A loose, improperly torqued or defective
knock sensor will decrease spark advance and reduce power. Replace defective knock
sensors and install using the recommended torque specification.
g. Check for engine mechanical conditions such as low compression, worn piston rings,
worn valves, worn camshafts and related parts. An engine which has severe mechani-
cal wear, or has suffered internal mechanical damage must be rebuilt or replaced to re-
store lost power.
h. Check the engine oil level for being overfilled. Adjust the engine’s oil level, or change
the engine oil and filter, and top off to the correct level.
i. Check for an intake manifold or vacuum hose leak. Replace leaking gaskets or worn
vacuum hoses.
j. Check for dragging brakes and replace or repair as necessary.
k. Check tire air pressure and tire wear. Adjust the pressure to the recommended set-
tings. Check the tire wear for possible alignment problems causing increased rolling
resistance, decreased acceleration and increased fuel usage.
I. Check the octane rating of the fuel used during refilling, and use a higher octane rated
fuel.
3. Poor fuel economy
a. Inspect the air filter and check for any air restrictions going into the air filter housing.
Replace the air filter if it is dirty or contaminated.
b. Check the engine for tune-up and related adjustments. Replace worn ignition parts,
check the engine ignition timing and fuel mixture, and set to specifications if possible.
c. Check the tire size, tire wear, alignment and tire pressure. Large tires create more
rolling resistance, smaller tires require more engine speed to maintain a vehicle’s road
speed. Excessive tire wear can be caused by incorrect tire pressure, incorrect wheel
alignment or a suspension problem. All of these conditions create increased rolling
resistance, causing the engine to work harder to accelerate and maintain a vehicle’s
speed.
d. Inspect the brakes for binding or excessive drag. A sticking brake caliper, overly ad-
justed brake shoe, broken brake shoe return spring, or binding parking brake cable or
linkage can create a significant drag, brake wear and loss of fuel economy. Check the
brake system operation and repair as necessary.
4. Engine runs on (diesels) when turned off
a. Check for idle speed set too high and readjust to specification.
b. Check the operation of the idle control valve, and replace if defective.
c. Check the ignition timing and adjust to recommended settings.
Check for defective
sensors or related components and replace if defective.
d. Check for a vacuum leak at the intake manifold or vacuum hose
and replace defective
gaskets or hoses.
e. Check the engine for excessive carbon build-up in the combustion chamber. Use a
recommended decarbonizing fuel additive or disassemble the cylinder head to remove
the carbon.
f. Check the operation of the engine fuel management system and replace defective sen-
sors or control units.
g. Check the engine operating temperature for overheating and repair as necessary. 5. Engine knocks and pinfls during heavy accele/ation, and on steep hills
a. Check the octane rating of the fuel used during refilling, and use a higher octane rated
fuel.
b. Check the ignition timing and adjust to recommended settings. Check for defective
sensors or related components and replace if defective.
c. Check the engine for excessive carbon build-up in the combustion chamber. Use a
recommended decarbonizing fuel additive or disassemble the cylinder head to remove
the carbon.
d. Check the spark plugs for the correct type, electrode gap and heat range. Replace worn
or damaged spark plugs. For severe or continuous high speed use, install a spark plug
that is one heat range colder.
e. Check the operation of the engine fuel management system and replace defective sen-
sors or control units.
f. Check for a restricted exhaust system. Check for bent or crimped exhaust pipes, or in-
ternally restricted mufflers or catalytic converters. Compare inlet and outlet tempera-
tures for the converter or muffler. If the inlet is hot, but outlet cold, the component is
restricted.
6. Engine atxelerates, but vehicle does not gain speed
a. On manual transmission vehicles, check for causes of a slipping clutch. Refer to the
clutch troubleshooting section for additional information.
b. On automatic transmission vehicles, check for a slipping transmission” Check the
transmission fluid level and condition. If the fluid level is too high, adjust to the cor-
rect level. If the fluid level is low, top off using the recommended fluid type. If the fluid
exhibits a burning odor, the transmission has been slipping internally. Changing the
fluid and filter may help temporarily, however in this situation a transmission may re-
quire overhauling to ensure long-term reliability.
Diesel Engines
1. Engine runs pOOr!y a. Check the injection pump timing and adjust to specification.
b. Check for air in the fuel lines or leaks, and bleed the air from the fuel system.
c. Check the fuel filter, fuel feed and return lines for a restriction and repair as necessary.
d. Check the fuel for contamination, drain and flush the fuel tank and replenish with fresh
fuel.
2. Enfline lacks power
a. Inspect the air intake system and air filter for restrictions and, if necessary, replace the
air filter.
b. Verify the injection pump timing and reset if out of specification.
c. Check the exhaust for an internal restriction and replace failed parts.
d. Check for a restricted fuel filter and, if restricted, replace the filter.
e. Inspect the fuel filler cap vent. When removing the filler cap, listen for excessive hiss-
ing noises indicating a blockage in the fuel filler cap vents, If the filler cap vents are
blocked, replace the cap.
f. Check the fuel system for restrictions and repair as necessary.
g. Check for low engine compression and inspect for external leakage at the glow plugs
or nozzles. If no external leakage is noted, repair or replace the engine.
ENGINE PERFORMANCE TROUBLESHOOTING HINTS When troubleshooting an engine running or performance condition, the mechanical
condition of the engine should be determined before lengthy troubleshooting procedures
are performed.
The engine fuel management systems in fuel injected vehicles rely on electronic sen-
sors to provide information to the engine control unit for precise fuel metering. Unlike
carburetors, which use the incoming air speed to draw fuel through the fuel metering jets
in order to provide a proper fuel-to-air ratio, a fuel injection system provides a specific
amount of fuel which is introduced by the fuel injectors into the intake manifold or intake
port, based on the information provided by electronic sensors.
The sensors monitor the engine’s operating temperature, ambient temperature and the
amount of air entering the engine, engine speed and throttle position to provide informa-
tion to the engine control unit, which, in turn, operates the fuel injectors by electrical
pulses. The sensors provide information to the engine control unit using low voltage
electrical signals. As a result, an unplugged sensor or a poor electrical contact could
cause a poor running condition similar to a failed sensor.
When troubleshooting a fuel related engine condition on fuel injected vehicles, care-
fully inspect the wiring and electrical connectors to the related components. Make sure
the electrical connectors are fully connected, clean and not physically damaged. If neces-
sary, clean the electrical contacts using electrical contact cleaner. The use of cleaning
agents not specifically designed for electrical contacts should not be used, as they could
leave a surface film or damage the insulation of the wiring.
The engine electrical system provides the necessary electrical power to operate the ve-
hicle’s electrical accessories, electronic control units and sensors. Because engine man-
agement systems are sensitive to voltage changes, an alternator which over or under-
charges could cause engine running problems or component failure. Most alternators
utilize internal voltage regulators which cannot be adjusted and must be replaced indi-
vidually or as a unit with the alternator.