MITSUBISHI DIAMANTE 1900 Repair Manual

BODYANDTRIil lo-13
1. Locate the release levers on the bottom front of
the seat cushion.
2. Grasp the release levers and lift the seat bot-
3. Place the seat cushion into place, and press
down to engage the retaining clips.
1 SEAT-BACK
1.
:.
4.
:ig. 57 Front seat mounting-199448 Galant L f
8. Tighten the front seat mounting nuts to 22 ft.
Ibs. (30 Nm). Tighten the rear mounting bolts to 33
ft. Ibs. (44 Nm).
9. Install the seat anchor covers.
IO. If equipped with power seats, attach the elec-
trical harness connector.
11. Connect the negative battery cable.
--_. -..-..
# See Figures 60, 61, and 62
shown, others similar
Rear Seats
SEAT CUSHION
ti See Figures 58 and 59 1. Remove the rear seat cushion,
2. Remove the seat back retaining bolts/nuts and
lift the seat back up and remove it from the vehicle.
To install:
3. Place the seat back into place and tighten the
retaining bolts/nuts to 16 ft. Ibs. (22 Nm). -
4. Install the seat cushion.
] REMOVAL &INSTALLATION
1. Disconnect the negative battery cable.
2. Remove the front seat assembly from the vehi-
cle.
3. Tag and detach the electrical connector(s).
4. Unfasten the retaining bolts, then remove the
power seat motor from the vehicle.
5. Installation is the reverse of the removal proce-
dure.

.
IO-14 BODYANDTRIM
TORQUE SPECIFICATIONS Components English Metric
Antenna nut 3 ft. Ibs. 4Nm
Door hinge-to-door bolts
1990-92 Mirage and 1990-93 Galant 12-19 ft. Ibs. 17-26 Nm
1993-96 Mirage, 1994-00 Galant, and Diamante 16 ft. Ibs. 22,Nm
1997-00 Mirage 20 ft. Ibs. 26 Nm
Door striker bolts 9ft. Ibs. 12Nm
Fender retaining screws 4 ft. Ibs. 6Nm
Front seat
Front retaining nuts 22 ft. Ibs. 30 Nm
Rear mounting bolts 33ft. Ibs. 44 Nm
Rear seat back retaining bolts 16 ft. Ibs. 22 Nm
Tailgate-to-hinge retaining nuts
10 ft. Ibs. 14 Nm
9315ocol
,

TROUBLESHOOTING INDEX 11-2
SECTION 1: ENGINE 11-2
SECTION 2: DRIVE TRAIN
11-3
SECTION 3:BRAKESYSTEM 11-3
SECTION 4:WHEELS,TIRES, STEERING,
AND SUSPENSION II-4
SECTION 5: ELECTRICAL
ACCESSORIES II-4
SECTION 6:lNSTRUMENTSAND
GAUGES II-5
SECTION 7:CLlMATE CONTROL II-5
DIAGNOSTIC PROCEDURES II-6
SECTION 1: ENGINE II-6
ENGINE STARTING PROBLEMS II-6
ENGINE RUNNING CONDITIONS II-7
ENGINE NOISES,ODORSAND
VIBRATIONS II-8
ENGINE ELECTRICALSYSTEM 11-8
ENGINE COOLING SYSTEM II-8
ENGINE EXHAUSTSYSTEM II-9
SECTION 2: DRIVE TRAIN
II-9
AUTOMATIC TRANSMISSION II-9
MANUALTRANSMISSION II-10
CLUTCH II-10
DIFFERENTIAL AND FINAL
DRIVE II-10
TRANSFER ASSEMBLY II-10
DRIVESHAFT II-10
AXLES II-II
OTHER DRIVE TRAIN
CONDITIONS II-II
SECTION 3:BRAKE SYSTEM II-II
BRAKESYSTEM
TROUBLESHOOTING II-II
SECTION 4:WHEELS, TIRES, STEERING
AND SUSPENSION II-12
WHEELSAND WHEEL
BEARINGS II-12
TIRES II-12
STEERING II-12
SUSPENSION II-12
DRIVING NOISES AND
VIBRATIONS II-13
SECTION 5:ELECTRlCAL
ACCESSORIES II-13 -
HEADLIGHTS II-13
TAIL, RUNNING AND SIDE MARKER
LIGHTS II-13
INTERIOR LIGHTS II-14
BRAKE LIGHTS II-14
WARNING LIGHTS II-14
TURN SlGNALAND4-WAYHAZARD
LIGHTS II-15
WINDSHIELD WIPERS II-15
SECTION 6:lNSTRUMENTSAND
GAUGUES II-15
I
SPEEDOMETER(CABLE
OPERATED) II-15
SPEEDOMETER(ELECTRONICALLY
OPERATED) II-16
FUEL,TEMPERATUREAkJD OIL
PRESSURE GAUGES II-16 SECTION 7:CLlMATECON
AIR CONDITIONER ll-
HEATER II-16 TR(
-16 IL II-16

11-2 TROUBLESHOOTING
Condition
Section/Item Number
The following troubleshooting charts are divided into 7 sections covering engine, drive train, brakes, wheels/tires/steering/suspension, electrical accessories, instruments and gauges,
and climate control. The first portion (or index) consists of a list of symptoms, along with section and item numbers. After selecting the appropriate condition, refer to the corresponding
diagnostic procedure in the second portion’s specified location.
INDEX
Gasoline Engines Engine turns over, but will not start
Engine does not turn over when attempting to start
Engine stalls immediately when started
Starter motor spins, but does not engage
Engine is difficult to start when cold
Engine is difficult to start when hot
Diesel Engines Engine turns over but won’t start
Engine does not turn over when attempting to start
Engine stalls after starting
Starter motor spins, but does not engage
Engine is difficult to start I-A, 1
l-A, 2
I-A, 3
I-A, 4
I-A, 5
I-A, 6
I-A, 1
l-A, 2
I-A, 3
I-A, 4
l-A, 5
Gasoline Engines Engine runs poorly, hesitates
Engine lacks power
Engine has poorfuel economy
Engine runs on (diesels) when turned off
Engine knocks and pings during heavy acceleration, and on steep hills
Engine accelerates but vehicle does not gain speed
Diesel Engines Engine runs poorly
Engine lacks power l-B, 1
I-B, 2
l-B, 3
I-B, 4
l-B, 5
I-B, 6
l-B,-1
l-B, 2
Engine makes a knocking or pinging noise when accelerating
Starter motor grinds when used
Engine makes a screeching noise
Engine makes a growling noise
Engine makes a ticking or tapping noise
Engine makes a heavy knocking noise
Vehicle has a fuel odor when driven
Vehicle has a rotten egg odor when driven
Vehicle has a sweet odor when driven
Engine vibrates when idling
Engine vibrates during acceleration
Battery goes dead while driving
Battery goes dead overnight
Engine overheats
Engine loses coolant
Engine temperature remains cold when driving
Engine runs hot
Exhaust rattles at idle speed
Exhaust system vibrates when driving
Exhaust system seems too low
Exhaust seems loud l-C, 1
l-C, 2
l-C, 3
I-C, 4
l-C, 5
I-C, 6
l-C, 7
l-C, 8
I-C, 9
I-C, 10
l-C, 11
l-C, 1
I-C, 2
I-D, 1
I-D, 2
I-D, 3
I-D, 4
l-F, 1
l-F, 2
I-F, 3
I-F, 4

I TROUBLESHOOTING II-3
Condition Section/hem Number
2-A, 1
2-A, 2
2-A, 3 Transmission shifts erratically
Transmission will not engage
Transmission will not downshift during heavy acceleration
Transmission grinds going into forward gears while driving
Transmission jumps out of gear
Transmission difficult to shift
Transmission leaks fluid 2-B, 1 2-C, 2
2-B, 2
2-B, 3 2-C, 2
2-B, 4
2-C,l
2-c,2
2-c,3
2-c,4
2-c,5
2-C,6 Clutch slips on hills or during sudden acceleration
Clutch will not disengage, difficult to shift
Clutch is noisy when the clutch pedal is pressed
Clutch pedal extremely difficult to press
Clutch pedal remains down when pressed
Clutch chatters when engaging
2-D, 1
2-D, 2 Differential makes a low pitched rumbling noise
Differential makes a howling noise
All Wheel and Four Wheel Drive Vehicles Leaks fluid from seals or vent after being driven
Makes excessive noise while driving
Jumps out of gear 2-E, 1
2-E, 2
2-E, 3
Rear Wheel, All Wheel and Four Wheel Drive Vehicles Clunking noise from center of vehicle shifting from forward to reverse
,Excessive vibration from center of vehicle when accelerating 2-F, l
2-F,2
All Wheel and Four Wheel Drive Vehicles , Front or rear wheel makes a clicking noise
Front or Rear wheel vibrates with increased speed 2-G,l
2-G,2
Front Wheel Drive Vehicles Front wheel makes a clicking noise
Rear wheel makes a clicking noise 2-G,3
2-G,4
Rear Wheel Drive Vehicles Front or rear wheel makes a clicking
Rear wheel shudders or vibrates noise 2-G,5
2-G,6
2-H, 1; 2-C, 1; 3-A, 9
2-H, 2; 2-C, 1; 3-A, 9 Burning odor from center of vehicle when accelerating
Engine accelerates, but vehicle does not gain speed
Brakes pedal pulsates or shimmies when pressed 3-A-l
Brakes make a squealing noise CI
3-A, 2
Brakes make a grinding noise
Vehicle pulls to one side during.braking
Brake pedal feels spongy or has excessive brake pedal travel
Brake pedal feel is firm, but brakes lack sufficient stopping power or fade 3-A, 3
3-A, 4
3-A, 5
3-A, 6

11-4 TROUBLESHOOTING
Condition
2 Section/Item Number ^i Vehicle has excessive front end dive or locks rear brakes too easily
3-A, 7
Brake pedal goes to floor when pressed and will not pump up
3-A, 8
Brakes make a burning odor
3-A, 9
All Wheel and Four Wheel Drive Vehicles Front wheel or wheel bearing loose
Rear wheel or wheel bearingloose
Front Wheel Drive Vehicles Front wheel or wheel bearing loose
Rear wheel or wheel bearing loose 4-A. 1
4-A: 1
4-A, 1
4-A, 2
Rear Wheel Drive Vehicles Front wheel or wheel bearing loose
Rear wheel or wheel bearing loose 4-A, 2
4-A, 1
Tires worn on inside tread
Tires worn on outside tread
s Tires worn unevenly 4-B, 1
4-B, 2
4-B, 3
Excessive play in steering wheel
Steering wheel shakes at cruising speeds
Steering wheel shakes when braking
Steering wheel becomes stiff when turned 4-c, 1
4-c, 2
3-A, 1
4-c, 4
Vehicle pulls to one side
Vehicle is very bouncy over bumps
Vehicle seems to lean excessively in turns
Vehicle ride quality seems excessively harsh
Vehicle seems low or leans to one side 4-D 1
4-D, 2
4-D, 3
4-D, 4
4-D, 5
Noises Vehicle makes a clicking noise when driven
Vehicle makes a clunking or knocking noise over bumps
Vehicle makes a low pitched rumbling noise when driven
Vehicle makes a squeaking noise over bumps
Vibrations Vehicle vibrates when driven 4-E, 1
4-E, 2
4-E, 3
4-E, 4

4-E, 5
One headlight only works on high or low beam
Headlight does not work on high or low beam
Headlight(s) very dim
Tail light, running light or side marker light inoperative
Tail light, running light or side marker light works intermittently
Tail light, running light or side marker light very dim 5-A, 1
5-A, 2
5-A, 3
/ .
5-B, 1
5-B, 2
5-B, 3
Interior light inoperative
Interior light works intermittently
Interior light very dim 5-c, 1
5-c, 2
5-c, 3

.
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.

11-8 TROUBLESHOOTING
Ignition systems may be controlled by, or linked to, the engine fuel management sys-
tem. Similar to the fuel injection system, these ignition systems rely on electronic sen-
sors for information to determine the optimum ignition timing for a given engine speed
and load. Some ignition systems no longer allow the ignition timing to be adjusted.
Feedback from low voltage electrical sensors provide information to the control unit to
determine the amount of ignition advance. On these systems, if a failure occurs the failed
component must be replaced. Before replacing suspected failed electrical components,
carefully inspect the wiring and electrical connectors to the related components. Make
sure the electrical connectors are fully connected, clean and not physically damaged. If
necessary, clean the electrical contacts using electrical contact cleaner. The use of clean-
ing agents not specifically designed for electrical contacts should be avoided, as they
could leave a surface film or damage the insulation of the wiring.
1. Engine makes a knocking or pinging noise when accelerating
a. Check the octane rating of the fuel being used. Depending on the type of driving or
driving conditions, it may be necessary to use a higher octane fuel.
b. Verify the ignition system settings and operation. Improperly adjusted ignition timing
or a failed component, such as a knock sensor, may cause the ignition timing to ad-
vance excessively or prematurely. Check the ignition system operation and adjust, or
replace components as needed.
c. Check the spark plug gap, heat range and condition. If the vehicle is operated in se-
vere operating conditions or at continuous high speeds, use a colder heat range spark
plug. Adjust the spark plug gap to the manufacturer’s recommended specification and
replace worn or damaged spark plugs.
2. Sfarter motor grinds when used
a. Examine the starter pinion gear and the engine ring gear for damage, and replace dam-
aged parts.
b. Check the starter mounting bolts and housing. If the housing is cracked or damaged
replace the starter motor and check the mounting bolts for tightness.
3. Engine makes a screeching noise
a. Check the accessory drive belts for looseness and adjust as necessary.
b. Check the accessory drive belt tensioners for seizing or excessive bearing noises and
replace if loose, binding, or excessively noisy.
c. Check for a seizing water pump. The pump may not be leaking; however, the bearing
may be faulty or the impeller loose and jammed. Replace the water pump.
4. Engine makes a growling noise
a. Check for a loose or failing water pump. Replace the pump and engine coolant.
b. Check the accessory drive belt tensioners for excessive bearing noises and replace if
loose or excessively noisy.
5. Engine makes a ticking or tapping noise
a. On vehicles with hydraulic lash adjusters, check for low or dirty engine oil and top off
or replace the engine oil and filter.
b. On vehicles with hydraulic lash adjusters, check for collapsed lifters and replace failed
components.
c. On vehicles with hydraulic lash adjusters, check for low oil pressure caused by a re-
stricted oil filter, worn engine oil pump, or oil pressure relief valve.
d. On vehicles with manually adjusted valves, check for excessive valve clearance or
worn valve train parts. Adjust the valves to specification or replace worn and defective
parts.
e. Check for a loose or improperly tensioned timing belt or timing chain and adjust or re-
place parts as necessary.
f. Check for a bent or sticking exhaust or intake valve. Remove the engine cylinder head
to access and replace.
6. Engine makes a heavy knocking noise
a. Check for a loose crankshaft pulley or flywheel; replace and torque the mounting
bolt(s) to specification.
b. Check for a bent connecting rod caused by a hydro-lock condition. Engine disassem-
bly is necessary to inspect for damaged and needed replacement parts.
c. Check for excessive engine rod bearing wear or damage. This condition is also asso-
ciated with low engine oil pressure and will require engine disassembly to inspect for
damaged and needed replacement parts,
7. Vehicle has a fuel odor when driven ’ a. Check the fuel gauge level. If the fuel gauge registers full, it is possible that the odor is
caused by being filled beyond capacity, or some spillage occurred during refueling.
The odor should clear after driving an hour, or twenty miles, allowing the vapor canis-
ter to purge.
b. Check the fuel filler cap for looseness or seepage. Check the cap tightness and, if
loose, properly secure. If seepage is noted, replace the filler cap.
c. Check for loose hose clamps, cracked or damaged fuel delivery and return lines, or
leaking components or seals, and replace or repair as necessary. d. Check the vehicle’s fuel economy. If fuel consumption has increased due to a failed
component, or if the fuel is not properly ignited due to an ignition related failure, the
catalytic converter may become contaminated. This condition may also trigger the
check engine warning light. Check the spark plugs for a dark, rich condition or verify
the condition by testing the vehicle’s emissions. Replace fuel fouled spark plugs, and
test and replace failed components as necessary.
5. Vehicle has a rotten egg odor when driven
a. Check for a leaking intake gasket or vacuum leak causing a lean running condition. A
lean mixture may result in increased exhaust temperatures, causing the catalytic con-
verter to run hotter than normal. This condition may also trigger the check engine
warning light. Check and repair the vacuum leaks as necessary.
b. Check the vehicle’s alternator and battery condition. If the alternator is overcharging,
the battery electrolyte can be boiled from the battery, and the battery casing may begin
to crack, swell or bulge, damaging or shorting the battery internally. If this has oc-
curred, neutralize the battery mounting area with a suitable baking soda and water
mixture or equivalent, and replace the alternator or voltage regulator. Inspect, service,
and load test the battery, and replace if necessary.
9. Vehicle has a sweet odor when driven
a. Check for an engine coolant leak caused by a seeping radiator cap, loose hose clamp,
weeping cooling system seal, gasket or cooling system hose and replace or repair as
needed.
b. Check for a coolant leak from the radiator, coolant reservoir, heater control valve or
under the dashboard from the heater core, and replace the failed part as necessary.
c. Check the engine’s exhaust for white smoke in addition to a sweet odor. The presence
of white, steamy smoke with a sweet odor indicates coolant leaking into the combus-
tion chamber. Possible causes include a failed head gasket, cracked engine block or
cylinder head. Other symptoms of this condition include a white paste build-up on the
inside of the oil filler cap, and softened, deformed or bulging radiator hoses.
19. Engine vibraies when idling
a. Check for loose, collapsed, or damaged engine or transmission mounts and repair or
replace as necessary.
b. Check for loose or damaged engine covers or shields and secure or replace as neces-
sary.
11. Engine vibrates during acceleration
a. Check for missing, loose or damaged exhaust system hangers and mounts; replace or
repair as necessary.
b. Check the exhaust system routing and fit for adequate clearance or potential rubbing;
repair or adjust as necessary.
7. Battery goes dead while driving
a. Check the battery condition. Replace the battery if the battery will not hold a charge or
fails a battery load test. If the battery loses fluid while driving, check for an overcharg-
ing condition. If the alternator is overcharging, replace the alternator or voltage regula-
tor. (A voltage regulator is typically built into the alternator, necessitating alternator re-
placement or overhaul.)
b. Check the battery cable condition. Clean or replace corroded cables and clean the bat-
tery terminals.
c. Check the alternator and voltage regulator operation. If the charging system is over or
undercharging, replace the alternator or voltage regulator, or both.
d. Inspect the wiring and wire connectors at the alternator for looseness, a missing .
ground or defective terminal, and repair as necessary.
e. Inspect the alternator drive belt tension, tensioners and condition. Properly tension the
drive belt, replace weak or broken tensioners, and replace the drive belt if worn or
cracked.
2. Battery goes dead overnight
a. Check the battery condition. Replace the battery if the battery will not hold a charge or
fails a battery load test.
b. Check for a voltage draw, such as a trunk light, interior light or glove box light staying
on. Check light switch position and operation, and replace if defective.
c. Check the alternator for an internally failed diode, and replace the alternator if defec-
tive.
1. Engine overheats
a. Check the coolant level. Set the heater temperature to full hot and check for internal air
pockets, bleed the cooling system and inspect for leakage. Top off the cooling system
with the correct coolant mixture.
b. Pressure test the cooling system and radiator cap for leaks. Check for seepage caused
by loose hose clamps, failed coolant hoses, and cooling system components such as
the heater control valve, heater core, radiator, radiator cap, and water pump. Replace
defective parts and fill the cooling system with the recommended coolant mixture.