1900 MITSUBISHI DIAMANTE spark plugs replace

ENGINEANDENGINEOVERHALJL 3-5
Fig. 15 Camshaft, rocker arm and shaft as-
remblies-2.01 SOHC engine
remove the lifter from the bore in the rocker arm. It is
recommended that all of the rocker arms and lash ad-
justers be replaced at the same time.
1. Disconnect the negative battery cable.
2. Remove the valve cover.
3. Matchmark the distributor to the cylinder
head and remove the distributor.
4. Remove camshaft timing belt.
5. Working in a crisscross pattern from the cen-
ter outward, loosen the camshaft bearing caps in
gradual steps.
6. Remove the rocker arms, shafts and bearing
caps as an assembly.
*It is essential that all parts be kept in the
same order and orientation for reinstallation.
Be sure to mark and separate parts, so parts
will not be mixed during reassembly.
7. Disassemble rocker shaft assembly. Starting
at rear bearing cap, slide each piece off shafts.
*Inspect the roller surfaces of the rockers.
Replace if there are any signs of damage or
if the roller does not turn smoothly. Check
the inside bore of the rockers and lifter for
wear.
To install:
8. Apply a drop of sealant to the rear edges of
the end caps.
9. Install the assembly into the front bearing
cap, making sure the notches in the rocker shafts are
facing up. Insert the installation bolt, but do not
tighten at this point.
10. Install the remaining cap bolts. Tighten all
bolts evenly and gradually to 15 ft. Ibs. (20 Nm). Re-
move the lash adjuster retainers.
11. Install the timing belt as required.
12. Align the matchmarks and install the distribu-
tor.
13. Remove the lash adjuster retaining tools. 14. Install the valve cover, with a new gasket and
semi-circular packing in place.
15. Connect the negative battery cable.
16. Run the engine and check ignition timing.
1.6L and 2.OL DOHC (Turbo and Non-turbo)
Engines
6 See Figure 16
1. Disconnect the negative battery cable.
2. Remove the valve cover and discard the gas-
ket.
3. Install lash adjuster retainer tools MD998443
or equivalent, to the rocker arm.
4. Remove the rocker shaft hold-down bolts
gradually and evenly and remove the rocker shaft/arm
assemblies.
5. If disassembly is required, keep all parts in
the exact order of removal. Inspect the roller surfaces
of the rockers. Replace if there are any signs of dam-
age or if the roller does not turn smoothly. Check the
inside bore of the rockers and the adjuster tip for
wear.
To install: 6. Lubricate the rocker shaft with clean engine
oil and install the rockers and springs in their proper
places.
7. Install the rocker shaft assemblies on the en-
gine. Tighten the bolts gradually and evenly to 21-25
ft. Ibs. (29-35 Nm).
*When installing the rocker arm shaft,
make certain the notch is properly located.
8. Remove the lash adiuster retainina tools
9. Install the valve cover with a new gasket.
10. Connect the negative battery cable.
F :ig. 16 Camshaft, rocker arm and shaft as
s iemblies-1.6L and 2.OL DOHC engines
*o Nm
IILlbs -
9315390 3
2.4L Engine
# See Figures 17, 16, and 19
1. Disconnect the negative battery cable.
2. Remove the accelerator cable from the retain-
ing clamps and position the accelerator cable out of
the way.
3. Remove the air intake hose.
4. Disconnect the breather hose and the PCV
hose.
5. Disconnect the spark plug cables from the
spark plugs.
6. Remove the rocker cover and gasket.
7. Install lash adjuster retainer tools MD998443
or equivalent, to the rocker arm.
8. Remove the rocker shaft hold-down bolts
gradually and evenly and remove the rocker shaft/arm
assemblies.
9. Disassemble the rockers and the rocker shaft
springs from the rocker shafts. If they are to be
reused, note the location and positionrng of all rocker
shaft components. It is recommended that all lash
adjusters and rockers be replaced as a complete set.
To install: 10. Immerse the lash adjusters in clean diesel
fuel, and using a small wire, move the plunger up
and down four or five times. while pushing down
lightly on the check ball in order to bleed the air from
the adjuster.
11. Install the lash adjusters to the rocker arms
and attach the special holding tool.
12. Lubricate the rocker shaft with clean engine
oil and install the rocker arms.
13. Temporarily tighten the rocker shaft assembly
with the mounting bolts so that all rocker arms on the
inlet valve side do not push on the valves,
14. Fit the rocker shaft springs from above and
position them so that they are at right angles to the
plug side. Install the rocker springs before installing
the exhaust side rocker shaft and rocker arm assem-
bly.
15. Install the exhaust side rocker shaft assembly
in the engine. Tighten the rocker shaft mounting bolts
gradually and evenly to 23 ft. Ibs. (32 Nm).
16. Remove the lash adjuster retaining tools.
17. Install the rocker cover and tighten the
mounting bolts to 30 inch Ibs. (3 Nm).
18. Reinstall the spark plug wires to the spark
plugs.
19. Reconnect the PCV and breather hoses.
20. Install the air intake hose.
21. Reattach the accelerator cable brackets and
reconnect the accelerator cable.
22. Connect the negative battery cable.
3.OL SOHC Engine
6 See Figures 20 and 21
On this engine, the hydraulic lash adjusters are
built into the rocker arms,
1. Disconnect the negative battery cable.
2. Remove the valve cover. Install lash adjuster
retainer tools MD998443 or equivalent, to prevent the
auto-lash adjuster from falling out of the rocker arm.
3. Loosen rocker arm and shaft assembly evenly
in several steps. Remove the rocker arm and shaft as-
sembly as a complete unit.
4. Remove the rear camshaft bearing cap and
slide the rocker arms, springs and washers from the
shaft. If they are to be reused, note the location and
positioning of all rocker shaft components. It is rec-

3-24 ENGINEANDENGINEOVERHAUL
Intake side Front of engine
e
Exhaust side
7923PG13 Fig. 110 Cylinder head bolt loosening se-
uuence-Mirage with 1.5L (4615) ermine
inwe side 0 Front of engine
((9
Exhaust side
7923PG14 Fig. 111 Cyllnder head bolt tightening se-
quence-Mirage with 1.5L (4615) engine
12. Disconnect the electrical harness plugs from
the following:
l Crankshaft Position (CKP) and Camshaft
Position (CMP) sensors
l Heated Oxygen (HO*S) sensor l Engine Coolant Temperature (ECT) sensor
and gauge sender
l Idle Speed Control (ISC) motor l Throttle Position (TP) sensor l Intake Air Temperature (IAT) sensor l Exhaust Gas Recirculation (EGR) tempera-
ture sensor
13. Disconnect electrical harness plugs from the
ignition distributor, fuel injectors, power transistor
and ground cable.
14. Disconnect the engine control wiring har-
ness.
15. Remove the clamp that holds the power steer-
ing pressure hose to the engine mounting bracket.
16. Place a jack and wood block under the oil
pan and carefully lift just enough to take the weight
off the engine mounting bracket and remove the
bracket.
17. Remove the valve cover.
18. Remove the timing belt upper cover.
19. Rotate the crankshaft clockwise and align the
timing marks.
20. Attach the timing belt to the camshaft
sprocket with cord or a wire tie.
21. Secure the camshaft from turning and remove
the camshaft sprocket with the timing belt attached.
22. Remove the timing belt rear upper cover.
23. Remove the exhaust pipe from the exhaust
manifold.
24. Loosen the cylinder head mounting bolts in
sequence using three steps.
25. Remove the cylinder head.
To install:
26. Thoroughly clean the mating surfaces of the
head and block. 27. Place a new head gasket on the cylinder
block with the identification marks facing upward. Do
not use sealer on the gasket.
28. Carefully install the cylinder head on the
block. Tighten the cylinder head bolts as outlined in
the followlng steps:
a. Tighten the bolts to 36 ft. Ibs. (49 Nm) in
the correct sequence
b. Loosen the bolts completely in the reverse
of the tightening order,
c. Tighten the bolts, in sequence, to 14 ft.
Ibs. (20 Nm)
d. Tighten each bolt, in sequence, 90 degrees
e. Tighten each bolt, in sequence, an addi-
tional 90 degrees
29. Install a new exhaust pipe gasket and connect
the exhaust pipe to the manifold.
30. Install the upper rear timing cover.
31. Align the timing marks and install the cam
sprocket. Torque the retaining bolt to 51 ft. Ibs. (76
Nm). Check the belt tension and adjust, if necessary.
Install the outer timing cover.
32. Install the valve cover and torque the retain-
ing bolts to 16 inch Ibs. (1.8 Nm).
33. Install the engine mount bracket and remove
the support jack.
34. Install the clamp that holds the power steer-
ing pressure hose to the engine mounting bracket.
35. Attach the following electrical connectors:
l CKP and CMP sensors l HOPS sensor l ECT sensor and gauge sender l ISC motor l TP sensor l IAT sensor l EGR temperature sensor
36. Connect wiring for the ignition distributor,
fuel injectors, power transistor and ground cable.
37. Connect the engine control wiring harness.
38. Replace the O-rings and connect the fuel
lines.
39. Install the air cleaner assembly. Connect the
breather hose.
40. Fill the system with coolant.
41. Connect the negative battery cable.
1.8L Engine
# See Figures 112 and 113
1. Relieve fuel system pressure. Disconnect the
negative battery cable.
2. Remove the air cleaner assembly.
3. Drain the cooling system.
Never open, service or drain the radiator or
cooling system when hot; serious burns can
occur from the steam and hot coolant. Also,
when draining engine coolant, keep in mind
that cats and dogs are attracted to ethylene
glycol antifreeze and could drink any that is
lefl in an uncovered container or in puddles
on the ground. This will prove fatal in suffi-
cient quantities. Always drain coolant into a
sealable container. Coolant should be reused
unless it is contaminated or is several years
old.
4. Disconnect the brake booster vacuum hose
and PVC valve connection. 5. Note the locations, then disconnect the vac-
uum hoses from the intake and throttle body.
6. Remove the upper radiator hose, overflow
tube and the water hose from the thermostat to the
throttle body.
7. Disconnect the fuel feed and return lines.
8. Unplug the accelerator cable connection from
the throttle body.
9. Detach the wiring from the oil pressure
switch.
10, Disconnect the wiring from the following
components:
l Heated Oxygen (HO*S) sensor l Engine Coolant Temperature (ECT) sensor
and gauge sender
l Idle Air Control (IAC) motor l Exhaust Gas Recirculation (EGR) tempera-
ture sensor
l Throttle Position (TP) sensor l Knock sensor l Fuel injectors
11. Remove the spark plug wires.
12. Unbolt the control harness assembly and po-
sition aside.
13. Remove the thermostat housing, thermostat
and the thermostat case with O-ring from the engine.
14. Remove the rocker cover.
15. Remove the timing belt upper cover.
16. Rotate the crankshaft clockwise and align the
timing marks.
17. Attach the timing belt to the camshaft
sprocket with cord or a wire tie.
18. Secure the camshaft from turning and remove
the camshaft sprocket with the timing belt attached.
19. Remove the timing belt rear upper cover.
20. Loosen the cylinder head bolts in two or three
steps in the proper sequence.
21. Remove the cylinder head from the engine.
Intake side
Front of engine c=>
I
Exhaust side
Loosening &der 7923PG15 Fig. 112 Cylinder head bolt loosening se-
quence-l .8L engine
intake side Front of engine *
Exhaust side libhtenng order
Fig. 113 Cylinder head bolt torque se-
quence-l .8L engine

ENGINEANDENGINEOVERHAUL 3-53
16. Torque the bearing cap bolts in the following
sequence: No. 3, No. 2, No. 1 and No. 4 to 85 inch
Ibs. (10 Nm).
17. Repeat the sequence increasing the torque to
14 ft. Ibs. (20 Nm).
18. Remove the auto lash adjuster retainer tools
from the rocker arms.
19. Install the camshaft sprocket and bolt.
20. Using camshaft sprocket holding tool
MB9g67 and MD998719 or equivalent, hold the
sprocket and tighten the bolt to 65 ft. Ibs. (90 Nm).
21. Install the timing belt and valve covers.
22. Using a new O-ring, install the distributor ex-
tension housing.
23. Install the intake manifold plenum stay
bracket.
24. Install the distributor assembly Be sure to
align the rotor and distributor housing matchmarks.
25. Connect the negative battery cable and check
for leaks.
3.5L Engine
+ See Figures 211 and 212
1. Disconnect the negative battery cable.
2. Remove the timing belt. Refer to the timing
belt procedure in this section.
3. Remove the rocker arm cover.
4. Install the lash adjuster clips on the rocker
arms, then loosen the bearing cap bolts. Do not re-
move the bolts from the bearing caps.
5. Remove the rocker arms, shafts and bearing
caps as an assembly.
6. Remove the camshafts.
To install: 7. Lubricate the camshafts with engine oil and
position them on the cylinder heads.
8. Position the dowel Dins as shown in the
drawing.
9. Install the bearing caps/rocker arm assem-
blies. Tighten the bolts to 23 ft. Ibs. (31 Nm).
10. hstall the rocker arm cover using a new gas-
ket.
11. Install the timing belt and remaining compo-
nents Refer to the timing belt procedure in this sec-
tion.
12. Connect the negative battery cable.
INSPECTION
Camshaft Lobe Liff
Camshaft lobe lift is the amount (measured in
inches or millimeters) that the camshaft is capable of
LIFTING the valve train components in order to open
the valves. The lobe lift is a measure of how much
taller the “egg shaped” portion of the camshaft lobe
is above the base or circular portion of the shaft lobe.
Lift is directly proportional to how far the valves can
open and a worn camshaft (with poor lobe lift) cannot
fully open the valves. The lobe lift therefore can be
directly responsible for proper or poor engine perfor-
mance.
Lobe lift can be measured in 2 ways, depending
on what tools are available and whether or not the
camshaft has been removed from the engine. A dial
gauge can be used to measure the lift with the
camshaft installed, while a micrometer is normally
only used once the shaft has been removed from the
engine.
10 Rocker arm shaft
11 Lash ad,uster
12 Rocker arm C
13 Rocker arm six,,
14 Lash adluster
15 Thrust case
16 orng
17 Camshan
:ig. 211 Exploded view of the camshaft mounting-3.51 engine 1923PGD
Rear bank Front bank
7923PGD4 Fig. 212 Camshaft dowel position during in-
stallation-3.51 engine
DIAL GAUGE METHOD
Lobe lift may be checked with the camshaft in-
stalled. In all cases, a dial gauge is positroned some-
where on the valve train (pushrod, lifter, or camshaft
itself) and the camshaft is then turned to measure the
lift.
Check the lift of each lobe in consecutive order
and make a note of the reading.
1. Remove the valve cover for access to the
camshaft.
2. Install a dial indicator so that the actuating
point of the indicator is directly placed on the
camshaft.
*A remote starter can be used to turn the
engine over during the next steps. If a re-
mote starter is not available, remove the
spark plugs in order to relieve engine com-
pression, and turn the engine over using a
large wrench or socket on the crankshaft
damper bolt. BE SURE to only turn the engine
in the normal direction of rotation.
3. Turn the crankshaft over until the tappet is on
the base circle of the camshaft lobe.
4. Zero the dial indicator. Continue to rotate the
crankshaft slowly until the pushrod (or camshaft
lobe) is in the fully raised position.
5. Compare the total lift recorded on the dial indi-
cator with the elevation specification shown in the
Engine Specification chart.
To check the accuracy of the original indicator
reading, continue to rotate the crankshaft until the in-
dicator reads zero. If the lift on any lobe is below
specified wear limits listed, the camshaft and the
valve tappets must be replaced.
6. Install the valve cover(s).
MICROMETER
) See Figure 213
A micrometer may used to measure camshaft lobe
lift, but this is usually only after it has been removed
from the engine. Once the valve cover is removed
I
@
Fig. 213 Camshaff lobe IIR Is measured In

3-58 ENGINEANDENGINEOVERHAUL '
*The editors at Chilton feel that most engine
machining should be performed by a profes-
sional machine shop. Don’t think of it as
wasting money, rather, as an assurance that
the job has been done right the first time.
There are many expensive and specialized
tools required to perform such tasks as bor-
ing and honing an engine block or having a
valve job done on a cylinder head. Even in-
specting the parts requires expensive mi-
crometers and gauges to properly measure
wear and clearances. Also, a machine shop
can deliver to you clean, and ready to as-
semble parts, saving you time and aggrava-
tion. Your maximum savings will come from
performing the removal, disassembly, as-
sembly and installation of the engine and
purchasing or renting only the tools required
to perform the above tasks. Depending on
the particular circumstances, you may save
40 to 60 percent of the cost doing these your-
self.
A complete rebuild or overhaul of an engine in-
volves replacing all of the moving parts (pistons,
rods, crankshaft, camshaft, etc.) with new ones and
machining the non-moving wearing surfaces of the
block and heads. Unfortunately, this may not be cost
effective. For instance, your crankshaft may have
been damaged or worn, but it can be machined un-
dersize for a minimal fee.
So, as you can see, you can replace everything in-
side the engine, but, it is wiser to replace only those
parts which are really needed, and, if possible, repair
the more expensive ones. Later in this section, we
will break the engine down into its two main compo-
nents: the cylinder head and the engine block. We
will discuss each component, and the recommended
parts to replace during a rebuild on each. spect the component, buy the necessary parts and OVERHAULTIPS
deliver these to a shop for actual machine work.
Much of the assembly work (crankshaft, bearings, Aluminum has become extremely popular for use
piston rods, and other components) is well within the in engines, due to its low weight. Observe the follow-
scope of the do-it-yourself mechanic’s tools and abil- ing precautions when handling aluminum parts:
ities. You will have to decide for yourself the depth of
l Never hot tank aluminum parts (the caustic hot
involvement you desire in an engine repair or rebuild. 6nk solution will eat the aluminum.
l Remove all aluminum parts (identification tag,
TOOLS etc.) from engine parts prior to the tanking.
l Always coat threads lightly with engine oil or
The tools required for an engine overhaul or parts
anti-seize compounds before installation, to prevent
replacement will depend on the depth of your in-
seizure.
volvement. With a few exceptions, they will be the
l Never overtighten bolts or spark plugs espe-
tools found in a mechanic’s tool kit (see Section 1 of
this manual). More in-depth work will require some cially in aluminum threads.
When assembling the engine, any parts that will
or all of the following:
be exposed to frictional contact must be prelubed to
l A dial indicator (reading in thousandths)
provide lubrication at initial start-up. Any product
mounted on a universal base
specifically formulated for this purpose can be used,
l Micrometers and telescope gauges
* Jaw and screw-type pullers but engine oil is not recommended as a prelube in
most cases.
‘ Scraper
When semi-permanent (locked, but removable) in-
l Valve spring compressor
stallation of bolts or nuts is desired, threads should l Ring groove cleaner l Piston ring expander and compressor be cleaned and coated with Loctite@ or another simi- l Ridge reamer , lar, commercial non-hardening sealant. l Cylinder hone or glaze breaker l Plastigage@ l Engine stand
The use of most of these tools is illustrated in
this section. Many can be rented for a one-time use
from a local parts jobber or tool supply house spe-
cializing in automotive work.
Occasionally, the use of special tools is called for.
See the information on Special Tools and the Safety
Notice in the front of this book before substituting
another tool. CLEANING
) See Figures 227, 228, 229, 230, and 231
Before the engine and its components are in-
spected, they must be thoroughly cleaned. You will
need to remove anv enaine varnish, oil sludoe and/or
c arbon deposits from ail of the componentsio insure
a In accurate inspection. A crack in the engine block or
c :ylinder head can easily become overlooked if hidden
t ry a layer of sludge or carbon.
Most engine overhaul procedures are fairly stan-
dard. In addition to specific parts replacement proce-
dures and specifications for your individual engine,
this section is also a guide to acceptable rebuilding
procedures. Examples of standard rebuilding practice
are given and should be used along with specific de-
tails concerning your particular engine.
Competent and accurate machine shop services
will ensure maximum performance, reliability and en-
gine life. In most instances it is more profitable for
the do-it-yourself mechanic to remove, clean and in- Fig. 227 Thoroughly clean the gasket sur-
faces of the cylinder head as well as . . .
Fig. 229 Use a ring expander tool to remove
the piston rings
fccs3911 ::“,z s,rpuse,a piece of fn old ring to 1
clean the grooves Be careful the ring can
230 Clean the piston ring grooves us-
ing a ring groove cleaner tool, or . . .

ENGINEAND ENGINEOVERHAUL 3-59
Most of the cleaning process can be carried out
with common hand tools and readily available sol-
vents or solutions. Carbon deposits can be chipped
away using a hammer and a hard wooden chisel. Old
gasket material and varnish or sludge can usually be
removed using a scraper and/or cleaning solvent. Ex-
tremely stubborn deposits may require the use of a
power drill wrth a wire brush. If using a wire brush,
use extreme care around any critical machined sur-
faces (such as the gasket surfaces, bearing saddles,
cylinder bores, etc.). USE OF A WIRE BRUSH IS NOT
RECOMMENDED ON ANY ALUMINUM COMPO-
NENTS Always follow any safety recommendations
given by the manufacturer of the tool and/or solvent.
You should always wear eye protection during any
cleaning process involvrng scraping, chipping or
spraying of solvents.
An alternative to the mess and hassle of cleaning
the parts yourself is to drop them off at a local garage
or machine shop. They will, more than likely, have
the necessary equrpment to properly clean all of the
parts for a nominal fee.
Always wear eye protection during any clean-
ing process involving scraping, chipping or
spraying of solvents.
Remove any oil galley plugs, freeze plugs and/or
pressed-in bearings and carefully wash and degrease
all of the engine components including the fasteners
and bolts. Small parts such as the valves, springs,
etc., should be placed in a metal basket and allowed
to soak. Use pipe cleaner type brushes, and clean all
passageways in the components. Use a ring ex-
pander and remove the rings from the pistons. Clean
the piston ring grooves with a special tool or a piece
of broken ring Scrape the carbon off of the top of the
piston. You should never use a wire brush on the
pistons. After preparing all of the piston assemblies
in this manner, wash and degrease them again.
Use extreme care when cleaning around the
cylinder head valve seats. A mistake or slip
may cost you a new seat.
When cleaning the cylinder head, remove carbon
from the combustron chamber with the valves in-
stalled. This will avoid damaging the valve seats.
:ig. 234 Drill out the damaged threads with
he specified size bit. Be sure to drill corn.
rletely through the hole or to the bottom oi
I blind hole REPAIRING DAMAGEDTHREADS
# See Figures 232, 233, 234, 235 and 236
Several methods of repairing damaged threads are
available Heli-Coil@ (shown here), Keenserts@ and
Microdop are among the most widely used. All in-
volve basically the same principle-drilling out
stripped threads, tapping the hole and installing a
prewound insert-making welding, plugging and
oversize fasteners unnecessary.
Two types of thread repair inserts are usually sup-
plied: a standard type for most inch coarse, rnch fine,
metric course and metrrc fine thread sizes and a
spark lug type to fit most spark plug port sizes. Con-
sult the individual tool manufacturers catalog to de-
termine exact applications. Typical thread repair kits
will contain a selection of prewound threaded inserts,
a tap (corresponding to the outside diameter threads
of the insert) and an installation tool. Spark plug in-
serts usually differ because they require a tap
equipped wrth pilot threads and a combined
reamer/tap section. Most manufacturers also supply
blister-packed thread repair Inserts separately in ad-
dition to a master kit containing a variety of taps and
inserts plus installation tools
Before attempting to repair a threaded hole, re-
move any snapped, broken or damaged bolts or
studs. Penetrating oil can be used to free frozen
threads. The offending item can usually be removed
with locking pliers or using a screw/stud extractor.
After the hole is clear, the thread can be reparred, as
shown in the series of accompanying illustrations
and in the krt manufacturers instructions.
THREADED
lCCS3039
replaced with thread repair inserts
:ig. 235 Using the kit, tap the hole in order
o receive the thread insert. Keep the tap
veil oiled and back it out frequently to avoid
:logging the threads
To properly rebuild an engine, you must first re-
move it from the vehicle, then disassemble and diag-
nose it. Ideally you should place your engine on an
engine stand. This affords you the best access to the
engine components. Follow the manufacturers direc-
tions for using the stand with your particular engine.
Remove the flywheel or flexplate before installing the
engine to the stand.
Now that you have the engine on a stand, and as-
suming that you have drained the oil and coolant
from the engine, it’s time to strip it of all but the nec-
essary components. Before you start disassembling
the engine, you may want to take a moment to draw
some pictures, or fabricate some labels or containers
to mark the locations of various components and the
bolts and/or studs which fasten them. Modern day
engines use a lot of little brackets and clips which
hold wiring harnesses and such, and these holders
are often mounted on studs and/or bolts that can be
easily mixed up. The manufacturer spent a lot of time
and money designing your vehicle, and they wouldn’t
have wasted any of it by haphazardly placing brack-
ets, clips or fasteners on the vehicle. If it’s present
when you disassemble it, put it back when you as-
semble, you will regret not remembering that little
bracket which holds a wire harness out of the path of
a rotating part.
You should begin by unbolting any accessories
still attached to the engine, such as the water pump,
power steering pump, alternator, etc. Then, unfasten
any manifolds (intake or exhaust) which were not re-
moved during the engine removal procedure. Finally,
Fig. 233 Standard thread repair insert (left),
and spark plug thread insert
im3043 Fig. 236 Screw the insert onto the installer
1001 until the tang engages the slot. Thread
‘he insert into the hole until it is l/4-l/~ turn
lelow the top surface, then remove the tool
and break off the tano usina a uunch

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.