width CHRYSLER VOYAGER 2003 User Guide

CONDITION POSSIBLE CAUSES CORRECTION
OIL CONSUMPTION OR SPARK
PLUGS FOULED1. PCV system malfunction. 1. Check system and repair as
necessary. (Refer to 25 -
EMISSIONS CONTROL/
EVAPORATIVE EMISSIONS/PCV
VALVE - DIAGNOSIS AND
TESTING)
2. Worn, scuffed or broken rings. 2. Hone cylinder bores. Install new
rings.
3. Carbon in oil ring slots. 3. Install new rings.
4. Rings fitted too tightly in grooves. 4. Remove rings and check
grooves. If groove is not proper
width, replace piston.
5. Worn valve guide(s). 5. Replace cylinder head assembly.
6. Valve stem seal(s) worn or
damaged.6. Replace seal(s).
DIAGNOSIS AND TESTING - ENGINE OIL LEAK
INSPECTION
Begin with a thorough visual inspection of the
engine, particularly at the area of the suspected leak.
If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
(2) Add an oil soluble dye (use as recommended by
manufacturer). Start the engine and let idle for
approximately 15 minutes. Check the oil dipstick to
make sure the dye is thoroughly mixed as indicated
with a bright yellow color under a black light.
(3) Using a black light, inspect the entire engine
for fluorescent dye, particularly at the suspected area
of oil leak. If the oil leak is found and identified,
repair as necessary.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24 km (15 miles), and
repeat inspection.
(5)If the oil leak source is not positively
identified at this time, proceed with the air leak
detection test method as follows:
²Disconnect the fresh air hose (make-up air) at
the cylinder head cover and plug or cap the nipple on
the cover.
²Remove the PCV valve hose from the cylinder
head cover. Cap or plug the PCV valve nipple on the
cover.
²Attach an air hose with pressure gauge and reg-
ulator to the dipstick tube.
CAUTION: Do not subject the engine assembly to
more than 20.6 kpa (3 PSI) of test pressure.²Gradually apply air pressure from 1 psi to 2.5
psi maximum while applying soapy water at the sus-
pected source. Adjust the regulator to the suitable
test pressure that provides the best bubbles which
will pinpoint the leak source. If the oil leak is
detected and identified, repair per service manual
procedures.
²If the leakage occurs at the crankshaft rear oil
seal area, refer to the section, Inspection for Rear
Seal Area Leak.
(6) If no leaks are detected, turn off the air supply.
Remove the air hose, all plugs, and caps. Install the
PCV valve and fresh air hose (make-up air). Proceed
to next step.
(7) Clean the oil off the suspect oil leak area using
a suitable solvent. Drive the vehicle at various
speeds approximately 24 km (15 miles). Inspect the
engine for signs of an oil leak by using a black light.
NOTE: If oil leakage is observed at the dipstick tube
to block location; remove the tube, clean and reseal
using MoparTStud & Bearing Mount (press fit tube
applications only), and for O-ring style tubes,
remove tube and replace the O-ring seal.
INSPECTION FOR REAR SEAL AREA LEAKS
Since it is sometimes difficult to determine the
source of an oil leak in the rear seal area of the
engine, a more involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.
If the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
9 - 82 ENGINE 3.3/3.8LRS
ENGINE 3.3/3.8L (Continued)
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Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum, with 552 kPa (80 psi) rec-
ommended.
Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage per cylinder.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
STANDARD PROCEDURE
STANDARD PROCEDURE - MEASURING
BEARING CLEARANCE USING PLASTIGAGE
Engine crankshaft bearing clearances can be deter-
mined by use of Plastigage or equivalent. The follow-
ing is the recommended procedure for the use of
Plastigage:
(1) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(2) Place a piece of Plastigage across the entire
width of the bearing shell in the cap approximately
6.35 mm (1/4 in.) off center and away from the oil
holes (Fig. 3). (In addition, suspected areas can be
checked by placing the Plastigage in the suspected
area). Torque the bearing cap bolts of the bearing
being checked to the proper specifications.
(3) Remove the bearing cap and compare the
width of the flattened Plastigage with the metric
scale provided on the package. Locate the band clos-est to the same width. This band shows the amount
of clearance in thousandths of a millimeter. Differ-
ences in readings between the ends indicate the
amount of taper present. Record all readings taken.
Compare clearance measurements to specs found in
engine specifications (Refer to 9 - ENGINE - SPECI-
FICATIONS).Plastigage generally is accompa-
nied by two scales. One scale is in inches, the
other is a metric scale.
NOTE: Plastigage is available in a variety of clear-
ance ranges. Use the most appropriate range for
the specifications you are checking.
(4) Install the proper crankshaft bearings to
achieve the specified bearing clearances.
STANDARD PROCEDURE - FORM-IN-PLACE
GASKETS AND SEALERS
There are numerous places where form-in-place
gaskets are used on the engine. Care must be taken
when applying form-in-place gaskets to assure
obtaining the desired results.Do not use form-in-
place gasket material unless specified.Bead size,
continuity, and location are of great importance. Too
thin a bead can result in leakage while too much can
result in spill-over which can break off and obstruct
fluid feed lines. A continuous bead of the proper
width is essential to obtain a leak-free gasket.
There are numerous types of form-in-place gasket
materials that are used in the engine area. Mopart
Engine RTV GEN II, MopartATF-RTV, and Mopart
Gasket Maker gasket materials, each have different
properties and can not be used in place of the other.
MOPARtENGINE RTV GEN IIis used to seal
components exposed to engine oil. This material is a
specially designed black silicone rubber RTV that
retains adhesion and sealing properties when
exposed to engine oil. Moisture in the air causes the
material to cure. This material is available in three
ounce tubes and has a shelf life of one year. After one
year this material will not properly cure. Always
inspect the package for the expiration date before
use.
MOPARtATF RTVis a specifically designed
black silicone rubber RTV that retains adhesion and
sealing properties to seal components exposed to
automatic transmission fluid, engine coolants, and
moisture. This material is available in three ounce
tubes and has a shelf life of one year. After one year
this material will not properly cure. Always inspect
the package for the expiration date before use.
MOPARtGASKET MAKERis an anaerobic type
gasket material. The material cures in the absence of
air when squeezed between two metallic surfaces. It
will not cure if left in the uncovered tube. The
Fig. 3 Plastigage Placed in Lower ShellÐTypical
1 - PLASTIGAGE
9 - 84 ENGINE 3.3/3.8LRS
ENGINE 3.3/3.8L (Continued)
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DESCRIPTION SPECIFICATION
Clearance in Piston @
21É C (70É F)0.006±0.019 mm
(0.0002±0.0007 in.)
Clearance in Connecting
Rod(Interference Fit)
Diameter 22.87±22.88 mm
(0.9007±0.9009 in.)
Length
Ð3.3L 67.25±67.75 mm
(2.648±2.667 in.)
Ð3.8L 71.25±71.75
(2.805±2.824 in.)
Piston Rings
Ring End GapÐTop
Compression Ring0.18±0.38 mm
(0.007±0.015 in.)
Wear Limit 1.0 mm
(0.039 in.)
Ring End GapÐ2nd
Compression Ring0.28±0.57 mm
(0.011±0.022 in.)
Wear Limit 1.0 mm
(0.039 in.)
Ring End GapÐOil
Control Steel Rails0.23±0.78 mm
(0.009±0.030 in.)
Wear Limit 1.88 mm
(0.074 in.)
Ring Side ClearanceÐ
Top Compression Ring
Ð3.3L 0.030±0.080 mm
(0.0012±0.0031 in.)
Ð3.8L 0.030±0.069 mm
(0.0012±0.0027 in.)
Wear Limit 0.10 mm
(0.004 in.)
Ring Side ClearanceÐ
2nd Compression Ring
Ð3.3L 0.030±0.095 mm
(0.0012±0.0037 in.)
Ð3.8L 0.041±0.085 mm
(0.0016±0.0033 in.)
Wear Limit 0.13 mm
(0.005 in.)DESCRIPTION SPECIFICATION
Ring Side ClearanceÐOil
Ring Pack0.039±0.200 mm
(0.0015±0.0078 in.)
Wear Limit 0.266 mm
(0.009 in.)
Ring WidthÐTop
Compression Ring
Ð3.3L 1.46±1.49 mm
(0.0575±0.058 in.)
Ð3.8L 1.175±1.190 mm
(0.0462±0.0468 in.)
Ring WidthÐ2nd
Compression Ring
Ð3.3/3.8L1.46±1.49 mm
(0.0575±0.058 in.)
Ring WidthÐOil Ring
(Steel Rails)
Ð3.3L 0.435±0.490 mm
(0.017±0.019 in.)
Ð3.8L 0.435±0.510 mm
(0.017±0.020 in.)
Connecting Rod
Bearing Clearance 0.019±0.065 mm
(0.0008±0.0026 in.)
Wear Limit 0.074 mm
(0.003 in.)
Side Clearance 0.13±0.32 mm
(0.005±0.013 in.)
Wear Limit 0.38 mm
(0.015 in.)
Crankshaft
Material Nodular Iron
Connecting Rod Journal
Diameter57.979±58.005 mm
(2.2827±2.2837 in.)
Main Bearing Journal
Diameter63.993±64.013 mm
(2.5194±2.5202 in.)
Journal Out-of-Round
(Max.)0.025 mm
(0.001 in.)
Journal Taper (Max.) 0.025 mm
(0.001 in.)
End Play 0.09±0.24 mm
(0.0036±0.0095 in.)
Wear Limit 0.381 mm
(0.015 in.)
9 - 92 ENGINE 3.3/3.8LRS
ENGINE 3.3/3.8L (Continued)
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DESCRIPTION SPECIFICATION
Main Bearing Diametrical
Clearance
ÐNo. 1, 2, 3, 4 0.011±0.055 mm
(0.0005±0.0022 in.)
Wear Limit 0.076 mm
(0.003 in.)
Camshaft
Journal Diameter
No.1 50.724±50.775 mm
(1.997±1.999 in.)
No.2 50.317±50.368 mm
(1.9809±1.9829 in.)
No.3 49.936±49.987 mm
(1.9659±1.9679 in.)
No.4 49.530±49.581 mm
(1.9499±1.9520 in.)
Bearing ClearanceÐ
Diametrical0.025±0.101 mm
(0.001±0.004 in.)
Bearing Clearance (Max.
allowable)0.127 mm
(0.005 in.)
End Play 0.254±0.508 mm
(0.010±0.020 in.)
(Max. allowable) 0.304 mm
(0.012 in.)
Camshaft Bearing
Diameter
No. 1 50.800±50.825 mm
(1.9999±2.0009 in.)
No. 2 50.393±50.419 mm
(1.9839±1.9849 in.)
No. 3 50.013±50.038 mm
(1.9690±1.9699 in.)
No. 4 49.606±49.632 mm
(1.9529±1.954 in.)
Exhaust Valve Timing
ClosesÐ3.3L (ATDC) 13É
ClosesÐ3.8L (ATDC) 18É
OpensÐ3.3L (BBDC) 43É
OpensÐ3.8L (BBDC) 46É
DurationÐ3.3L 236É
DurationÐ3.8L 244ÉDESCRIPTION SPECIFICATION
Intake Valve Timing
ClosesÐ3.3L (ABDC 52É
ClosesÐ3.8L (ABDC 63É
OpensÐ3.3L (ATDC) 6É
OpensÐ3.8L (ATDC) 1É
DurationÐ3.3L 226É
DurationÐ3.8L 242É
Valve OverlapÐ3.3L 7É
Valve OverlapÐ3.8L 17É
Lifters
Type Hydraulic Roller
Diameter O.D. 22.949±22.962 mm
(0.903±0.904 in.)
Clearance In Block 0.020±0.061 mm
0.0007±0.0024 in.)
Cylinder Head
Gasket Thickness
(Compressed)0.65±0.75 mm
(0.025±0.029 in.)
Valve Seat
Angle 44.5±45É
Valve Seat Runout
(Service Limits)0.0762 mm
(0.003 in.)
Valve Seat WidthÐIntake
& Exhaust1.50±2.00 mm
(0.057±0.078 in.)
Valve Guide
Guide Bore Diameter
(Std.)6.975±7.00 mm
(0.274±0.275 in.)
Valves
Valve Lift (Zero
Lash)ÐIntake & Exhaust
Ð3.3L 9.80 mm
(0.385 in.)
Ð3.8L 11.0 mm
(0.433 in.)
Face AngleÐIntake 45±45.5É
Face AngleÐExhaust 45±45.5É
Head DiameterÐIntake 47.87±48.13 mm
(1.88±1.89 in.)
Head DiameterÐExhaust 35.37±35.63 mm
(1.39±1.40 in.)
RSENGINE 3.3/3.8L9-93
ENGINE 3.3/3.8L (Continued)
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(2) Assemble gasket to cylinder cover by inserting
the fasteners through each bolt hole on cover and
gasket (Fig. 25).
(3) Install the cylinder head cover and bolts (Fig.
26).
(4) Tighten cylinder head cover bolts to 12 N´m
(105 in. lbs.) (Fig. 26).
(5) Connect crankcase vent hose.
(6) Connect spark plug wires to spark plugs.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves have chrome plated valve stems with
four-bead lock grooves. The valve stem seals are
made of Viton rubber.
OPERATION
The two valves per cylinder are opened using
hydraulic lifters, push rods, and rocker arms.
STANDARD PROCEDURE - REFACING VALVES
AND VALVE SEATS
The intake and exhaust valves and seats are
machined to specific angles (Fig. 27).
VALVES
(1) Inspect the remaining margin after the valves
are refaced (Fig. 28). (Refer to 9 - ENGINE - SPEC-
IFICATIONS)
VALVE SEATS
CAUTION: Remove metal from valve seat only. Do
not remove material from cylinder head (Fig. 29).
(1) When refacing valve seats, it is important that
the correct size valve guide pilot be used for reseat-ing stones. A true and complete surface must be
obtained.
(2) Measure the concentricity of valve seat using
dial indicator (Fig. 30). Total runout should not
exceed 0.051 mm (0.002 in.) total indicator reading.
(3) Inspect the valve seat using Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seatLIGHTLYwith Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to top edge of valve face, lower valve seat with
a 15 degree stone. If the blue is transferred to the
bottom edge of valve face raise valve seat with a 65
degrees stone.
NOTE: Valve seats which are worn or burned can
be reworked, provided that correct angle and seat
width are maintained. Otherwise cylinder head must
be replaced.
Fig. 27 Valve Face and Seat
1 - SEAT WIDTH
2 - FACE ANGLE
3 - SEAT ANGLE
4 - SEAT CONTACT AREA
Fig. 28 Valve Margin
1 - VALVE FACE
2 - VALVE MARGIN
Fig. 29 Refacing Valve Seats
1 - REFACING STONE MUST NOT CUT INTO CYLINDER HEAD
2-STONE
3 - PILOT
4 - SEAT
9 - 104 ENGINE 3.3/3.8LRS
CYLINDER HEAD COVER - LEFT (Continued)
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(4) When seat is properly positioned the width of
intake and exhaust seats should be 1.50±2.00 mm
(0.059±0.078 in.) (Fig. 27).
(5) After grinding the valve seats or faces, install
the valve in cylinder head and check valve installed
height by measuring from valve tip to spring seat
(Fig. 31). Remove valve from cylinder head and grind
valve tip until within specifications. Check valve tip
for scoring. The tip chamfer should be reground (if
necessary) to prevent seal damage when the valve is
installed.
(6) Check the valve spring installed height after
refacing the valve and seat (Fig. 31).
If valves and/or seats are reground, measure
the installed height of springs (Fig. 31), make
sure measurements are taken from top of
spring seat to the bottom surface of spring
retainer. If height is greater than specifica-
tions, install a 0.794 mm (0.0312 in.) spacer in
head counterbore to bring spring height back
within specifications.
REMOVAL
(1) With cylinder head removed, compress valve
springs using Valve Spring Compressor Tool
C-3422-D with adapter 8464 (Refer to 9 - ENGINE -
SPECIAL TOOLS).
(2) Remove valve retaining locks.
(3) Slowly release valve spring compressor.
Remove valve spring retainer, valve spring, and valve
stem seal.
(4) Before removing valves,remove any burrs
from valve stem lock grooves to prevent dam-
age to the valve guides.Identify valves to insure
installation in original location.
CLEANING
(1) Clean all valves thoroughly and discard
burned, warped and cracked valves.
INSPECTION
VALVES
(1) Clean and inspect valves thoroughly. Replace
burned, warped and cracked valves.
(2) Measure valve stems for wear (Fig. 32). For
valve specifications, (Refer to 9 - ENGINE - SPECI-
FICATIONS).
NOTE: Valve stems are chrome plated and should
not be polished (Fig. 32).
VALVE GUIDES
(1) Remove carbon and varnish deposits from
inside of valve guides with a reliable guide cleaner.
(2) Measure valve stem-to-guide clearance as fol-
lows:
(3) Install valve into cylinder head so it is 15 mm
(0.590 inch.) off the valve seat. A small piece of hose
may be used to hold valve in place.
(4) Attach dial indicator Tool C-3339 to cylinder
head and set it at right angle of valve stem being
measured (Fig. 33).
(5) Move valve to and from the indicator. For cler-
ance specifications, (Refer to 9 - ENGINE - SPECIFI-
CATIONS).
Fig. 30 Measurement of Valve Seat Runout
1 - DIAL INDICATOR
Fig. 31 Checking Valve and Spring Installed Height
1 - SPRING RETAINER
2 - VALVE INSTALLED HEIGHT* - 48.1±49.7 mm (1.89±1.95 in.)
3 - CYINDER HEAD SURFACE
4 - SPRING INSTALLED HEIGHT* - 41.1±42.7 mm (1.61±1.68 in.)
*(MEASURED FROM TOP OF SPRING SEAT)
RSENGINE 3.3/3.8L9 - 105
INTAKE/EXHAUST VALVES & SEATS (Continued)
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CONNECTING ROD BEARINGS
STANDARD PROCEDURE - MEASURING
CONNECTING ROD BEARING CLEARANCE
The bearing caps are not interchangeable and
should be marked at removal to ensure correct
assembly. The bearing shells must be installed with
the tangs inserted into the machined grooves in the
rods and caps. Install cap with the tangs on the same
side as the rod. Fit all rods on one bank until com-
plete. Connecting rod bearings are available in the
standard size and the following undersizes: 0.025
mm (0.001 in.) and 0.250 mm (0.010 in.).
CAUTION: Install the bearings in pairs. Do not use a
new bearing half with an old bearing half. Do not
file the rods or bearing caps.Measure connecting rod journal for taper and out-
of-round. (Refer to 9 - ENGINE/ENGINE BLOCK/
CRANKSHAFT - INSPECTION)
The connecting rod bearing clearances can be
determined by use of Plastigage or the equivalent.
The following is the recommended procedure for the
use of Plastigage:
(1) Rotate the crankshaft until the connecting rod
to be checked is at the bottom of its stroke.
(2) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(3) Place a piece of Plastigage across the entire
width of the bearing shell in the bearing cap approx-
imately 6.35 mm (1/4 in.) off center and away from
the oil hole. In addition, suspect areas can be
checked by placing Plastigage in that area.
(4) Assemble the rod cap with Plastigage in place.
Tighten the rod cap to the specified torque.Do not
rotate the crankshaft while assembling the cap
or the Plastigage may be smeared, giving inac-
curate results.
Fig. 59 Piston and Connecting Rod Positioning (Front View of Engine)
1 - MAJOR THRUST SIDE OF PISTON
2 - OIL SQUIRT HOLE
9 - 120 ENGINE 3.3/3.8LRS
PISTON & CONNECTING ROD (Continued)
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(5) Remove the bearing cap and compare the
width of the flattened Plastigage with the scale pro-
vided on the package (Fig. 60). Locate the band clos-
est to the same width. This band indicates the
amount of oil clearance. Differences in readings
between the ends indicate the amount of taper
present. Record all readings taken. Refer to Engine
Specifications (Refer to 9 - ENGINE - SPECIFICA-
TIONS).Plastigage generally is accompanied by
two scales. One scale is in inches, the other is a
metric scale. If the bearing clearance exceeds
wear limit specification, replace the bearing.
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING
(1) Wipe cylinder bore clean. Insert the ring and
push down with piston to ensure squareness in bore
to approximately 12 mm (0.50 in.) from top of cylin-
der bore. Check ring gap with a feeler gauge (Fig.
61). For clearance specification (Refer to 9 - ENGINE
- SPECIFICATIONS).
(2) Check piston ring to groove side clearance (Fig.
62). For clearance specification (Refer to 9 - ENGINE
- SPECIFICATIONS)
REMOVAL
(1) Remove piston and connecting rod. (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON & CONNECT-
ING ROD - REMOVAL)(2) Remove No. 1 and No.2 piston rings from pis-
ton using a ring expander tool (Fig. 65).
(3) Remove upper oil ring side rail (Fig. 64).
(4) Remove lower oil ring side rail (Fig. 64).
(5) Remove oil ring expander (Fig. 64).
INSTALLATION
(1) Install rings with manufacturers I.D. mark (if
present) facing up, to the top of the piston (Fig. 63).
CAUTION: Install piston rings in the following order:
1. Oil ring expander.
2. Upper oil ring side rail.
3. Lower oil ring side rail.
4. No. 2 Intermediate piston ring.
5. No. 1 Upper piston ring.
Fig. 60 Measuring Connecting Rod Bearing
Clearance
Fig. 61 Piston Ring Gap
1 - FEELER GAUGE
Fig. 62 Piston Ring Side Clearance
1 - FEELER GAUGE
RSENGINE 3.3/3.8L9 - 121
CONNECTING ROD BEARINGS (Continued)
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(4) Place a piece of Plastigage across the entire
width of the bearing shell in the cap approximately
6.35 mm (1/4 in.) off center and away from the oil
holes (Fig. 69). (In addition, suspected areas can be
checked by placing the Plastigage in the suspected
area). Torque the bearing cap bolts of the bearing
being checked to the proper specifications.
(5) Remove the bearing cap and compare the width
of the flattened Plastigage (Fig. 70) with the scale
provided on the package. Locate the band closest to
the same width. This band shows the amount of
clearance in thousandths. Differences in readings
between the ends indicate the amount of taper
present. Record all readings taken. (Refer to 9 -
ENGINE - SPECIFICATIONS)Plastigage gener-
ally is accompanied by two scales. One scale is
in inches, the other is a metric scale.
NOTE: Plastigage is available in a variety of clear-
ance ranges. Use the most appropriate range for
the specifications you are checking.
PLASTIGAGE METHODÐENGINE OUT-OF-VEHICLE
(1) With engine in the inverted position (crank-
shaft up) and mounted on a repair stand, remove
main journal cap.
(2) Remove oil from journal and bearing shell.
(3) Cut Plastigage to same length as width of the
bearing and place it in parallel with the journal axis
(Fig. 69).(4) Carefully install the main bearing cap and
tighten the bolts to specified torque.
CAUTION: Do not rotate crankshaft or the Plasti-
gage will be smeared.
(5) Carefully remove the bearing cap and measure
the width of the Plastigage at the widest part using
the scale on the Plastigage package (Fig. 70). Refer
to Engine Specifications for proper clearances (Refer
to 9 - ENGINE - SPECIFICATIONS). If the clearance
exceeds the specified limits, replace the main bear-
ing(s) with the appropriate size, and if necessary,
have the crankshaft machined to next undersize.
REMOVAL - CRANKSHAFT MAIN BEARINGS
(1) Remove the oil pan. (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL)
(2) Identify main bearing caps before removal.
(3) Remove bearing caps one at a time. Remove
upper half of bearing by inserting Special Main Bear-
ing Tool C-3059 (Fig. 71) into the oil hole of crank-
shaft.
(4) Slowly rotate crankshaft clockwise, forcing out
upper half of bearing shell.
INSTALLATION - CRANKSHAFT MAIN
BEARINGS
NOTE: One main bearing should be selectively fit-
ted while all other main bearing caps are properly
tightened.
Fig. 69 Plastigage Placed in Lower
1 - PLASTIGAGE
Fig. 70 Clearance Measurement
Fig. 71 Upper Main Bearing Removing/Installing
With Special Tool C-3059
1 - SPECIAL TOOL C-3059
2 - BEARING
3 - SPECIAL TOOL C-3059
4 - BEARING
9 - 124 ENGINE 3.3/3.8LRS
CRANKSHAFT MAIN BEARINGS (Continued)
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FUEL INJECTION
OPERATION
OPERATION - INJECTION SYSTEM
All engines used in this section have a sequential
Multi-Port Electronic Fuel Injection system. The MPI
system is computer regulated and provides precise
air/fuel ratios for all driving conditions. The Power-
train Control Module (PCM) operates the fuel injec-
tion system.
The PCM regulates:
²Ignition timing
²Air/fuel ratio
²Emission control devices
²Cooling fan
²Charging system
²Idle speed
²Vehicle speed control
Various sensors provide the inputs necessary for
the PCM to correctly operate these systems. In addi-
tion to the sensors, various switches also provide
inputs to the PCM.
The PCM can adapt its programming to meet
changing operating conditions.
Fuel is injected into the intake port above the
intake valve in precise metered amounts through
electrically operated injectors. The PCM fires the
injectors in a specific sequence. Under most operat-
ing conditions, the PCM maintains an air fuel ratio
of 14.7 parts air to 1 part fuel by constantly adjust-
ing injector pulse width. Injector pulse width is the
length of time the injector is open.
The PCM adjusts injector pulse width by opening
and closing the ground path to the injector. Engine
RPM (speed) and manifold absolute pressure (air
density) are theprimaryinputs that determine
injector pulse width.
OPERATION - MODES OF OPERATION
As input signals to the PCM change, the PCM
adjusts its response to output devices. For example,
the PCM must calculate a different injector pulse
width and ignition timing for idle than it does for
Wide Open Throttle (WOT). There are several differ-
ent modes of operation that determine how the PCM
responds to the various input signals.
There are two different areas of operation, OPEN
LOOP and CLOSED LOOP.
During OPEN LOOP modes the PCM receives
input signals and responds according to preset PCM
programming. Inputs from the upstream and down-
stream heated oxygen sensors are not monitored dur-
ing OPEN LOOP modes, except for heated oxygensensor diagnostics (they are checked for shorted con-
ditions at all times).
During CLOSED LOOP modes the PCM monitors
the inputs from the upstream and downstream
heated oxygen sensors. The upstream heated oxygen
sensor input tells the PCM if the calculated injector
pulse width resulted in the ideal air-fuel ratio of 14.7
to one. By monitoring the exhaust oxygen content
through the upstream heated oxygen sensor, the
PCM can fine tune injector pulse width. Fine tuning
injector pulse width allows the PCM to achieve opti-
mum fuel economy combined with low emissions.
For the PCM to enter CLOSED LOOP operation,
the following must occur:
(1) Engine coolant temperature must be over 35ÉF.
²If the coolant is over 35ÉF the PCM will wait 38
seconds.
²If the coolant is over 50ÉF the PCM will wait 15
seconds.
²If the coolant is over 167ÉF the PCM will wait 3
seconds.
(2) For other temperatures the PCM will interpo-
late the correct waiting time.
(3) O2 sensor must read either greater than 0.745
volts or less than 0.29 volt.
(4) The multi-port fuel injection systems has the
following modes of operation:
²Ignition switch ON (Zero RPM)
²Engine start-up
²Engine warm-up
²Cruise
²Idle
²Acceleration
²Deceleration
²Wide Open Throttle
²Ignition switch OFF
(5) The engine start-up (crank), engine warm-up,
deceleration with fuel shutoff and wide open throttle
modes are OPEN LOOP modes. Under most operat-
ing conditions, the acceleration, deceleration (with
A/C on), idle and cruise modes,with the engine at
operating temperatureare CLOSED LOOP modes.
IGNITION SWITCH ON (ZERO RPM) MODE
When the ignition switch activates the fuel injec-
tion system, the following actions occur:
²The PCM monitors the engine coolant tempera-
ture sensor and throttle position sensor input. The
PCM determines basic fuel injector pulse width from
this input.
²The PCM determines atmospheric air pressure
from the MAP sensor input to modify injector pulse
width.
When the key is in the ON position and the engine
is not running (zero rpm), the Auto Shutdown (ASD)
and fuel pump relays de-energize after approximately
14 - 18 FUEL INJECTIONRS
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