engine overheat MITSUBISHI DIAMANTE 1900 Repair Manual

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1-2 GENERALINFORMATIONAND MAINTENANCE
Chitton’s Total Car Care manual for the 199M10
Mitsubishi Mirage, Galant and Diamante is intended
to help you learn more about the inner workings of
your vehicle while saving you money on its upkeep
and operation.
The beginning of the book will likely be referred to
the most, since that is where you will find information
for maintenance and tune-up. The other sections deal
with the more complex systems of your vehicle. Oper-
ating systems from engine through brakes are cov-
ered to the extent that the average do-it-yourselfer be-
comes mechanically involved. This book will not
explain such things as rebuilding a differential for the
simple reason that the expertise required and the in-
vestment in special tools make this task uneconomi-
cal. It will, however, give you detailed instructions to
help you change your own brake pads and shoes, re-
place spark plugs, and perform many more jobs that
can save you money, give you personal satisfaction
and help you avoid expensive problems.
A secondary purpose of this book is a reference for
owners who want to understand their vehicle and/or
their mechanics better. In this case, no tools at all are
required.
Before removing any bolts, read through the entire
procedure. This will give you the overall view of what
tools and supplies will be required. There is nothing
more frustrating than having to walk to the bus stop
on Monday morning because you were short one bolt
on Sunday afternoon. So read ahead and plan ahead.
Each operation should be approached logically and
all procedures thoroughly understood before attempt-
ing any work.
All sections contain adjustments, maintenance, re-
moval and installation procedures, and in some cases,
repair or overhaul procedures. When repair is not con-
sidered practical, we tell you how to remove the part
and then how to install the new or rebuilt replacement.
In this way, you at least save labor costs. “Backyard”
repair of some components is just not practical.
Many procedures in this book require you to “label
and disconnect. . ” a group of lines, hoses or wires.
Don’t be lulled into thinking you can remember where
everything goes-you won’t. If you hook up vacuum
or fuel lines incorrectly, the vehicle may run poorly, if
at all. If you hook up electrical wiring incorrectly, you
may instantly learn a very expensive lesson.
You don’t need to know the official or engineering
name for each hose or line. A piece of masking tape
on the hose and a piece on its fitting will allow you to
assign your own label such as the letter A or a short name. As long as you remember your own code, the
lines can be reconnected by matching similar letters
or names. Do remember that tape will dissolve in
gasolrne or other fluids; if a component is to be
washed or cleaned, use another method of identifica-
tion. A permanent felt-tipped marker or a metal scribe
can be very handy for marking metal parts. Remove
any tape or paper labels after assembly.
It’s necessary to mention the difference between
maintenance and repair Maintenance includes rou-
tine inspections, adjustments, and replacement of
parts which show signs of normal wear Maintenance
compensates for wear or deterioration. Repair implies
that something has broken or is not working. A need
for repair is often caused by lack of maintenance. Ex-
ample, draining and refilling the automatic transaxle
fluid is maintenance recommended by the manufac-
turer at specific mileage intervals. Failure to do this
can shorten the life of the transmission/transaxle, re-
quiring very expensive repairs. While no maintenance
program can prevent items from breaking or wearing
out, a general rule can be stated: MAINTENANCE IS
CHEAPER THAN REPAIR.
Two basic mechanrc’s rules should be mentioned
here. First, whenever the left side of the vehicle or en-
gine is referred to, it is meant to specify the drivers
side. Conversely, the right side of the vehicle means
the passengers side. Second, screws and bolts are
removed by turning counterclockwise, and tightened
by turning clockwrse unless specifically noted.
Safety is always the most important rule. Con-
stantly be aware of the dangers involved in working
on an automobile and take the proper precautions.
See the informatron in this section regarding SER-
VICING YOUR VEHICLE SAFELY and the SAFETY
NOTICE on the acknowledgment page.
Pay attention to the instructions provided. There
are 3 common mistakes in mechanical work:
1. Incorrect order of assembly, disassembly or
adjustment. When taking something apart or putting
it together, performing steps in the wrong order usu-
ally just costs you extra time; however, it CAN break
something. Read the entire procedure before begin-
ning disassembly. Perform everything in the order in
which the instructions say you should, even if you
can’t immedrately see a reason for it. When you’re
taking apart something that is very intricate, you
might want to draw a picture of how it looks when as-
sembled at one point in order to make sure you get everything back in its proper position. We will supply
exploded views whenever possible. When making
adjustments, perform them in the proper order. One
adjustment possibly will affect another.
2. Overtorquing (or undertorquing). While it is
more common for overtorquing to cause damage,
undertorquing may allow a fastener to vibrate loose
causing serious damage. Especially when dealing
with aluminum parts, pay attention to torque specifi-
cations and utilize a torque wrench in assembly. If a
torque figure is not available, remember that if you
are using the right tool to perform the job, you will
probably not have to strain yourself to get a fastener
tight enough. The pitch of most threads is so slight
that the tension you put on the wrench will be multi-
plied many times in actual force on what you are
tightening. A good example of how critical torque is
can be seen in the case of spark plug installation, es-
pecially where you are putting the plug into an alu-
minum cylinder head. Too little torque can fail to
crush the gasket, causing leakage of combustion
gases and consequent overheating of the plug and
engine parts. Too much torque can damage the
threads or distort the plug, changing the spark gap.
There are many commercial products available for
ensuring that fasteners won’t come loose, even if they
are not torqued just right (a very common brand is
Loctite? If you’re worried
about getting something
together tight enough to hold, but loose enough to
avoid mechanical damage during assembly, one of
these products might offer substantial insurance. Be-
fore choosing a threadlocking compound, read the
label on the package and make sure the product is
compatible with the materials, fluids, etc. involved.
3. Crossthreading. This occurs when a part such
as a bolt is screwed into a nut or casting at the wrong
angle and forced. Crossthreading is more likely to
occur if access is difficult. It helps to clean and lubri-
cate fasteners, then to start threading the bolt, spark
plug, etc. with your fingers If you encounter resis-
tance, unscrew the part and start over again at a dif-
ferent angle until it can be inserted and turned several
times without much effort. Keep in mind that many
parts, especially spark plugs, have tapered threads,
so that gentle turning will automatically bring the part
you’re threading to the proper angle. Don’t put a
wrench on the part until its been tightened a couple
of turns by hand. If you suddenly encounter resis-
tance, and the part has not seated fully, don’t force it.
Pull it back out to make sure it’s clean and threading
properly.
Be sure to take your time and be patient, and al-
ways plan ahead. Allow yourself ample time to per-
form repairs and maintenance You may find main-
taining your car a satisfying and enjoyable
experience.
b See Figures 1 thru 15
Naturally, without the proper tools and equipment
it is impossible to properly service your vehicle. It
would also be virtually impossible
to catalog every
tool that you would need to perform all of the opera-
tions in this book. Of course, It would be unwise for
the amateur to rush out and buy an expensive set of
tools on the theory that he/she may need one or more
of them at some time, The best approach is to proceed slowly, gathering savings will
be far outweighed by frustration and
a good quality set of those tools that are used most mangled knuckles.
frequently Don’t be misled by the low cost of bargain Begin accumulating those tools that are used most
tools. It is far better to spend a little more for better frequently: those associated with routine maintenance
quality. Forged wrenches, 6 or 12-point sockets and and tune-up. In addition to the normal assortment of
fine tooth ratchets are by far preferable to their less screwdrivers and pliers, you should have the follow-
expensive counterparts. As any good mechanic can ing tools:
tell you, there are few worse experiences than trying
l Wrenches/sockets and combination open
to work on a vehicle with bad tools. Your monetary end/box end wrenches in sizes from %-% in. or

t
1-38 GENERALINFORMATIONAND MAINTENANCE
11 I Add the recommended automatic transaxle
fluid to the transaxle through the dipstick tube. You
will need a long necked funnel, or a funnel and tube
to do this. A quick check of the capacities chart later
in this Section will reveal the capacity of the transaxle
in your vehicle. On a first fill after removing the pan
and filter, this number should be cut into a ‘hand
checked on the dipstick before refilling.
12. With the transaxle in P, put on the parking
brake, block the front wheels, start the engine and let
it idle. DO NOT RACE THE ENGINE. DO NOT MOVE
THE LEVER THROUGH ITS RANGES.
13. With the lever in Park, check the fluid level. If
it’s OK, take the car out for a short drive, park on a
level surface, and check the level again, as outlined
earlier in this section. Add more fluid if necessary. Be
careful not to overfill, which will cause foaming and
w fluid loss. n of the transfer case filler
3. Remove the filler and the drain plug and allow
the oil to drain into the drain pan.
4. After the fluid has drained completely, install
the drain plug and tighten to 24 ft. Ibs. (32 Nm).
5. Refill the transfer case to the proper level with
Fig. 184 . . .
the transaxle case before in-
stalling the gasket
and pan onto the case FLUID RECOMMENDATIONS Hypoid gear oil SAE 75W-85W/75W-9OW conform-
ing to API specifications GL-4 or higher. The oil level
-‘-,*I’ -nnnh +‘* “%om edge of the oil filler hole.
nxfer raw filler nlm and tinhtm When adding fluid or refilling the transfer case,
use Hypoid gear oil SAE 75W-85W or 75W-9OW
conforming to API specifications 61-4 or higher.
LEVELCHECK 6. Install the tra .._._. ____ .._. T.-J _.._ .lJ . .._..
to 24 ft. lbs. (32 Nm).
7. Carefully lower the vehicle.
u See Figure 185
, 1 FLUID RECOMMENDATIONS
delivery service, the fluid should be changed accord-
ing to the severe service schedule.
The fluid must be hot before it is drained; a 20 u See Figure 187
Since fluid viscosity range may
vary depending on
specific temperature range of operation, please refer
~~
tne transaxle case.
You’ll be very sorry later if you do. bottom edge of the transfer case filler 1 1 Fig. 187 Rear axle lubricant application I
*If the drained fluld is discolored (brown or
1 plug hole chart black), thick, or pmmll~ hmmt nnrinmm I transaxle trouble .llln3llU ““III., url,““P s, probably due to overheat-
,r..rr,rA “#.a.- rrdr
trig, should be susp~~lr;u. lvUl vLlr J
transaxle should be inspected by a reliable
transaxle specialist to determine the prob-
lem.
5. Remove the pan and gasket.
6. Clean the pan with solvent and allow it to air
dry. If you use a rag to wipe out the pan, you risk
leaving bits of lint behind, which will clog the dinky
hydraulic passages in the bansaxle.
7. Remove the filter retaining bolts and remove
the filter from the valve bodv. lnsoect each component for leaking. Check the oil
he filler plug. If the oil is contami-
ry to replace it with new oil.
if% nn IPVPI z11rf2r~
level by removing t
nated, it is necessa
1. Park the vehi,., -.. ,-.“, __. ,“-_.
2. Remove the filler plug and make sure the oil
level reaches the lower edge of the filler plug hole.
3. Check to be sure that the oil is not noticeably
dirty and that it has the proper viscosity.
4. If necessary, add oil through the filler hole until
is runs out of the hole. to the accompanying chart for the proper fluid for
your vehicle.
LEVEL CHECK
1. Make sure the vehicle is parked on level
ground.
2. Remove the oil fill plug to check the oil level.
3. The oil level is sufficient if it reaches the lower
portion of the filler plug hole. If the fluid is low, add
as required through the filler plug.
To install: .
8. Install a new filter, then install the retaining
bolts and tighten them to 5 ft. Ibs. (7 Nm).
9. Position the gasket on the pan, then install
the pan. Tighten the bolts evenly and in rotation to
8-9ft. Ibs. (10-12 Nm.). Do not overtighten.
IO. Lower the vehicle. DRAIN & REFILL
I8 DRAIN & REFILL
u See Figure 188 ) See Figure- 14
1. Raise and safely support the vehicle, for access
to the transfer case.
2. Place a suitable drain pan under the transfer
case fluid drain plug. 1. Position the vehicle on a flat surface or raise
and safely support the vehicle in a level position.
2. Place a suitable drain pan under the rear axle.

I)
ENGINEANDENGINEOVERHAUL 3-65
10. Install the camshaft(s), rockers, shafts and
any other components that were removed for disas-
sembly.
GENERAL INFORMATION ways number 1. However, depending on the engine
placement, the front of the engine could either be the
flywheel or damper/pulley end. Generally the front of
the engine faces the front of the vehicle. Use a num-
ber punch or scribe and also mark the main bearing
caps from front to rear with the front most cap being
number 1 (if there are five caps, mark them 1 through
5, front to rear).
A thorough overhaul or rebuild of an engine block
would include replacing the pistons, rings, bearings,
timing belt/chain assembly and oil pump. For OHV
engines also include a new camshaft and lifters. The
block would then have the cylinders bored and honed
oversize (or if using removable cylinder sleeves, new
sleeves installed) and the crankshaft would be cut
undersize to provide new wearing surfaces and per-
feet clearances. However, your particular engine may Take special care when pushing the connect-
ing rod up from the crankshaft because the
sharp threads of the rod bolts/studs will
score the crankshaft journal. Insure that spe-
cial plastic caps are installed over them, or
cut two pieces of rubber hose to do the
same.
Again, rotate the engine, this time to position the
number one cylinder bore (head surface) up. Turn the
crankshaft until the number one piston is at the bot-
tom of its travel, this should allow the maximum ac-
cess to its connecting rod. Remove the number one
connecting rods fasteners and cap and place two
lengths of rubber hose over the rod bolts/studs to
protect the crankshaft from damage. Using a sturdy
wooden dowel and a hammer, push the connecting
rod up about 1 in. (25mm) from the crankshaft and
remove the upper bearing insert. Continue pushing
or tapping the connecting rod up until the piston
rings are out of the cylinder bore. Remove the piston
and rod by hand, put the upper half of the bearing in-
sert back into the rod, install the cap with its bearing
insert installed, and hand-tighten the cap fasteners. If
the parts are kept in order in this manner, they will
not get lost and you will be able to tell which bear-
ings came form what cylinder if any problems are
discovered and diagnosis is necessary. Remove all
the other piston assemblies in the same manner. On
V-style engines, remove all of the pistons from one
bank, then reposition the engine with the other cylin-
der bank head surface up, and remove that banks nis-
prevent the assemblies from being removed,
necessitating its removal. Fig. 260 Carefully tap the piston out of the
bore using a wooden dowel
There are several different types of ridge reamers
on the market, none of which are inexpensive, Unless
.3 “me.+ ,-ins, rdnnn;nn mh~lil.-linn ;I nn+:n:nnL.* l.^W
a ylwx “Gal “I cllylllc Ir;““ll”llly 13 dllLILlpxC”, ““I- row or rent a reamer.
1. Turn the crankshaft until the piston is at the
bottom of its travel.
2. Cover the head of the piston with a rag.
3. Follow the tool manufacturers instructions and housing or transmission mounting surface. You must
1 as many
II of the
~1SA~E~BLY
b See Figures 259 and 260
The engine disassembly instructions following as-
sume that you have the engine mounted on an engine
stand. If not, it is easiest to disassemble the engine
on a bench or the floor with it resting on the bell be able to access the connecting rod fasteners and
turn the crankshaft during disassembly. Also, all en-
gine covers (timing, front, side, oil pan, whatever)
should
are sei2
nletelv have already been removed. Engines which
,ed or locked up may not be able to be com-
r’-‘-‘, disassembled, and a core (salvage yard) en-
gine sh ould be purchased.
If no
t done during the cylinder head removal, re-
move the timing chain/belt and/or gear/sprocket as-
sembly. Remove the oil pick-up and pump assembly
and, if necessary, the pump drive. If equipped, re-
move any balance or auxiliary shafts. If necessary, re-
move the cylinder ridge from the top of the bore. See
the cylinder ridge removal procedure earlier in this
section.
Rotate the engine over so that the crankshaft is ex-
posed. Use a number punch or scribe and mark each
connecting rod with its respective cylinder number.
The cylinder closest to the front of the engine is al- cut away the ridge, exercising extreme care to avoid
~ ioo deepfy.
4. Remove the ridge reamer, the rag and
armings as possible. Continue until a
biter ridges have been removed. ton assemblies.
The only remaining component in the engine
block should now be the crankshaft. Loosen the main
bearing caps evenly until the fasteners can be turned
by hand, then remove them and the caps. Remove the
crankshaft from the engine block. Thoroughly clean
all of the components.
INSPECTION
Now that the engine block and all of its compo-
nents are clean, it’s time to inspect them for wear
and/or damage. To accurately inspect them, you will
need some specialized tools:
l Two or three separate micrometers to measure
the prstons and crankshaft journals
l A dial indicator l Telescoping gauges for the cylinder bores l A rod alignment fixture to check for bent con-
netting rods
If you do not have access to the proper tools,
you may want to bring the components to a shop
that does.
Generally, you shouldn’t expect cracks in the en-
gine block or its components unless it was known to
leak, consume or mix engine fluids, it was severely
overheated, or there was evidence of bad bearings
and/or crankshaft damage. A visual inspection

3-66 ENGINEANDENGINEOVERHAUL
should be performed on all of the components, but
just because you don’t see a crack does not mean it
is not there. Some more reliable methods for inspect-
ing for cracks include Magnaflux? a magnetic
process or Zyglo@‘, a dye penetrant. Magnaflux@ is
used only on ferrous metal (cast iron). Zyglo@ uses a
spray on fluorescent mixture along with a black light
to reveal the cracks. It is strongly recommended to
have your engine block checked professionally for
cracks, especially if the engine was known to have
overheated and/or leaked or consumed coolant. Con-
tact a local shop for availability and pricing of these
services.
Engine Block
ENGINE BLOCK BEARING ALIGNMENT
Remove the main bearing caps and, if still in:
stalled, the main bearing inserts. Inspect all of the
main bearing saddles and caps for damage, burrs or
high spots. If damage is found, and it is caused from
a spun main bearing, the block will need to be align-
bored or, if severe enough, replacement. Any burrs or
high spots should be carefully removed with a metal
file.
Place a straightedge on the bearing saddles, in the
engine block, along the centerline of the crankshaft. If
any clearance exists between the straightedge and the
saddles, the block must be align-bored.
Align-boring consists of machining the main
bearing saddles and caps by means of a flycutter that
runs through the bearing saddles.
DECK FLATNESS
The top of the engine block where the cylinder
head mounts is called the deck. Insure that the deck
surface is clean of dirt, carbon deposits and old gas-
ket material. Place a straightedge across the surface
of the deck along its centerline and, using feeler
gauges, check the clearance along several points. Re-
peat the checking procedure with the straightedge
placed along both diagonals of the deck surface. If
the reading exceeds 0.003 in. (0.076mm) within a 6.0
in. (152cm) span, or 0.006 in. (0.152mm) over the
total length of the deck, it must be machined.
CYLINDER BORES
$ See Figure 261
The cylinder bores house the pistons and are
slightly larger than the pistons themselves. A com-
mon piston-to-bore clearance is 0.0015-0.0025 in. (0.0381mm-O.0635mm). Inspect and measure the
cylinder bores. The bore should be checked for out-
of-roundness, taper and size. The results of this in-
spection will determine whether thecylinder can be
used in its existing size and condition, or a rebore to
the next oversize is required (or in the case of remov-
able sleeves, have replacements installed).
The amount of cylinder wall wear is always greater
at the top of the cylinder than at the bottom. This
wear is known as taper. Any cylinder that has a taper
of 0.0012 in. (0.305mm) or more, must be rebored.
Measurements are taken at a number of positions in
each cylinder: at the top, middle and bottom and at

two points at each position; that is, at a point 90 de-
grees from the crankshaft centerline, as well as a
point parallel to the crankshaft centerline. The mea-
surements are made with either a special dial indica-
tor or a telescopic gauge and micrometer. If the nec-
essary precision tools to check the bore are not
available, take the block to a machine shop and have
them mike it. Also if you don’t have the tools to check
the cylinder bores, chances are you will not have the
necessary devices to check the pistons, connecting
rods and crankshaft. Take these components with you
and save yourself an extra trip.
For our procedures, we will use a telescopic
gauge and a micrometer. You will need one of each,’
with a measuring range which covers your cylinder
bore size.
1, Position the telescopic gauge in the cylinder
bore, loosen the gauges lock and allow it to expand.
*Your first two readings will be at the top of
the cylinder bore, then proceed to the middle
and finally the bottom, making a total of six
measurements.

2. Hold the gauge square in the bore, 90 degrees
from the crankshaft centerline, and gently tighten the
lock. Tilt the gauge back to remove it from the bore.
3. Measure the gauge with the micrometer and
record the reading.
4. Again, hold the gauge square in the bore, this
time parallel to the crankshaft centerline, and gently
tighten the lock. Again, you will tilt the gauge back to
remove it from the bore.
5. Measure the gauge with the micrometer and
record this reading. The difference between these two
readings is the out-of-round measurement of the
cylinder.
6. Repeat steps 1 through 5, each time going to
the next lower position, until you reach the bottom of
the cylinder. Then go to the next cylinder, and con-
tinue until all of the cylinders have been measured.
The difference between these measurements will
tell you all about the wear in your cylinders. The
measurements which were taken 90 degrees from the
crankshaft centerline will always reflect the most
wear.,That is because at this position is where the en-
gine power presses the piston against the cylinder
bore the hardest. This is known as thrust wear. Take
your top, 90 degree measurement and compare it to
your bottom, 90 degree measurement. The difference
between them is the taper. When you measure your
pistons, you will compare these readings to your pis-
ton sizes and determine piston-to-wall clearance. crankshaft, but you should hardly feel them with your
fingernail. When measuring the crankshaft with a mi-
crometer, you will take readings at the front and rear
of each journal, then turn the micrometer 90 degrees
and take two more readings, front and rear. The dif-
ference between the front-to-rear readings is the jour-
nal taper and the first-to-90 degree reading is the
out-of-round measurement. Generally, there should
be no taper or out-of-roundness found, however, up
to 0.0005 in. (0.0127mm) for either can be over-
looked. Also, the readings should fall within the fac-
tory specifications for journal diameters.
If the crankshaft journals fall within specifications,
it is recommended that it be polished before being
returned to service. Polishing the crankshaft insures
that any minor burrs or high spots are smoothed,
thereby reducing the chance of scoring the new bear-
ings.
Pistons and Connecting Rods
PISTONS
N See Figure 262
The piston should be visually inspected for any
signs of cracking or burning (caused by hot spots or
detonation), and scuffing or excessive wear on the
skirts. The wrist pin attaches the piston to the con-
netting rod. The piston should move freely on the
wrist pin, both sliding and pivoting. Grasp the con-
netting rod securely, or mount it in a vise, and try to
rock the piston back and forth along the centerline of
the wrist pin. There should not be any excessive play
evident between the piston and the pin. If there are C-
clips retaining the pin in the piston then you have
wrist pin bushings in the rods. There should not be
any excessive play between the wrist pin and the rod
bushing. Normal clearance for the wrist pin is ap-
prox. 0.001-0.002 in. (0.025mm-0.051mm).
Use a micrometer and measure the diameter of the
piston, perpendicular to the wrist pin, on the skirt.
Compare the reading to its original cylinder measure-
ment obtained earlier. The difference between the two
readings is the piston-to-wall clearance. If the clear-
ante is within specifications, the piston may be used
as is. If the piston is out of specification, but the bore
is not, you will need a new piston. If both are out of
specification, you will need the cylinder rebored and
oversize pistons installed. Generally if two or more
pistons/bores are out of specification, it is best to re-
bore the entire block and purchase a complete set of
oversize pistons.
Crankshaft
Inspect the crankshaft for visible signs of wear or
damage. All of the journals should be perfectly round
and smooth. Slight scores are normal for a used

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

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.

TROUBLESHOOTING 11-9
c. On vehicles with electrically controlled cooling fans, check the cooling fan operation.
Check for blown fuses or defective fan motors, temperature sensors and relays, and
replace failed components.
d. Check for a coolant leak caused by a failed head gasket, or a porous water jacket cast-
ing in the cylinder head or engine block. Replace defective parts as necessary.
e. Check for an internally restricted radiator. Flush the radiator or replace if the blockage
is too severe for flushing.
f. Check for a damaged water pump. If coolant circulation is poor, check for a loose wa-
ter pump impeller. If the impeller is loose, replace the water pump.
2. Engine loses coolant
a. 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.
b. Check for a coolant leak caused by a failed head gasket, or a porous water jacket cast-
ing in the cylinder head or engine block. Replace defective parts as necessary.
3. Engine temperature remains co/d when driving
a. Check the thermostat operation. Replace the thermostat if it sticks in the open posi-
tion.
b. On vehicles with electrically controlled cooling fans, check the cooling fan operation.
Check for defective temperature sensors and stuck relays, and replace failed compo-
nents.
c. Check temperature gauge operation if equipped to verify proper operation of the
gauge. Check the sensors and wiring for defects, and repair or replace defective com-
ponents.
4. Engine runs hot
a. Check for an internally restricted radiator. Flush the radiator or replace if the blockage
is too severe for flushing.
b. Check for a loose or slipping water pump drive belt. Inspect the drive belt condition.
Replace the belt if brittle, cracked or damaged. Check the pulley condition and prop-
erly tension the belt.
c. Check the cooling fan operation. Replace defective fan motors, sensors or relays as
necessary.
d. Check temperature gauge operation if equipped to verify proper operation of the
gauge. Check the sensors and wiring for defects, and repair or replace defective com-
ponents.
e. Check the coolant level. Set the heater temperature to full hot, check for internal air
pockets, bleed the cooling system and inspect for leakage. Top off the cooling system
with the correct coolant mixture. Once the engine is cool, recheck the fluid level and
top off as needed.
NOTE: The engine cooling system can also be affected by an engine’s me-
chanical condition. A failed head gasket or a porous casting in the engine
block or cylinder head could cause a loss of coolant and result in engine
overheating.
Some cooling systems rely on electrically driven cooling fans to cool the radiator and
use electrical temperature sensors and relays to operate the cooling fan. When diagnos-
ing these systems, check for blown fuses, damaged wires and verify that the electrical
connections are fully connected, clean and not physically damaged. If necessary, clean
the electrical contacts using electrical contact cleaner. The use of cleaning igents not specifically designed for electrical contacts could leave a film or damage the insulation of
the wiring.
1. Exhaust rattles at idle speed
a. Check the engine and transmission mounts and replace mounts showing signs of
damage or wear.
b. Check the exhaust hangers, brackets and mounts. Replace broken, missing or dam-
aged mounts.
c. Check for internal damage to mufflers and catalytic converters. The broken pieces from
the defective component may travel in the direction of the exhaust flow and collect
and/or create a blockage in a component other than the one which failed, causing en-
gine running and stalling problems. Another symptom of a restricted exhaust is low
engine manifold vacuum. Remove the exhaust system and carefully remove any loose
or broken pieces, then replace any failed or damaged parts as necessary.
d. Check the exhaust system clearance, routing and alignment. If the exhaust is making
contact with the vehicle in any manner, loosen and reposition the exhaust system.
2. Exhaust system vibrates when driving
a. Check the exhaust hangers, brackets and mounts. Replace broken, missing or dam-
aged mounts.
b. Check the exhaust system clearance, routing and alignment. If the exhaust is making
contact with the vehicle in any manner, check for bent or damaged components and
replace, then loosen and reposition the exhaust system.
c. Check for internal damage to mufflers and catalytic converters. The broken pieces from
the defective component may travel in the direction of the exhaust flow and collect
and/or create a blockage in a component other than the one which failed, causing en-
gine running and stalling problems. Another symptom of a restricted exhaust is low
engine manifold vacuum. Remove the exhaust system and carefully remove any loose
or broken pieces, then replace any failed or damaged parts as necessary.
3. Exhaust system hangs too low
a. Check the exhaust hangers, brackets and mounts. Replace broken, missing or dam-
aged mounts.
b. Check the exhaust routing and alignment. Check and replace bent or damaged com-
ponents. If the exhaust is not routed properly, loosen and reposition the exhaust sys-
tern.
4. Exhaust sounds loud
a. Check the system for looseness and leaks. Check the exhaust pipes, clamps, flange
bolts and manifold fasteners for tightness. Check and replace any failed gaskets.
b. Check and replace exhaust silencers that have a loss of efficiency due to internally
broken baffles or worn packing material.
c. Check for missing mufflers and silencers that have been replaced with straight pipes
or with non-original equipment silencers.
NOTE: Exhaust system rattles, vibration and proper alignment should not
be overlooked. Excessive vibration caused by collapsed engine mounts,
damaged or missing exhaust hangers and misalignment may cause surface
cracks and broken welds, creating exhaust leaks or internal damage to ex-
haust components such as the catalytic converter, creating a restriction to
exhaust flow and loss of power.
1. Transmission shit& erratically
a. Check and if not within the recommended range, add or remove transmission fluid to
obtain the correct fluid level. Always use the recommended fluid type when adding
transmission fluid.
b. Check the fluid level condition. If the fluid has become contaminated, fatigued from
excessive heat or exhibits a burning odor, change the transmission fluid and filter us-
ing the recommended type and amount of fluid. A fluid which exhibits a burning odor
indicates that the transmission has been slipping internally and may require future re-
pairs.
c. Check for an improperly installed transmission filter, or missing filter gasket, and re-
pair as necessary.
d. Check for loose or leaking gaskets, pressure lines and fittings, and repair or replace as
necessary.
e. Check for loose or disconnected shift and throttle linkages or vacuum hoses, and re-
pair as necessary. ,
2. Transmission will not engage
a. Check the shift linkage for looseness, wear and proper adjustment, and repair as nec-
essary. b. Check for a loss of transmission fluid and top off as needed with the recommended
fluid.
c. If the transmission does not engage with the shift linkage correctly installed and the
proper fluid level, internal damage has likely occurred, requiring transmission removal
and disassembly.
3. Transmission will not downshift during heavy acceleration
a. On computer controlled transmissions, check for failed sensors or control units and
repair or replace defective components.
b. On vehicles with kickdown linkages or vacuum servos, check for proper linkage ad-
justment or leaking vacuum hoses or servo units.
NOTE: Mlany automatic transmissions use an electronic control module,
electrical sensors and solenoids to control transmission shifting. When
troubleshooting a vehicle with this type of system, be sure the electrical
connectors are fully connected, clean and not physically damaged. If nec-
essary, clean the electrical contacts using electrical contact cleaner. The
use of cleaning agents not specifically designed for electrical contacts
could leave a film or damage the insulation of the wiring.