Chrysler 1991 Operating manual

SERVICE
MANUAL
SUPPLEMENT
DIESEL ENGINE
REAR WHEEL DRIVE
TRUCK
D& W 250-350

TYSLER
MOTTOES
DIESEL ENGINE
SERVICE MANUAL
SUPPLEMENT
1991 1/2 DODGE TRUCKS
NOPART OF THISPUBLICATIONMAY BE
REPRODUCED,STORED INA RETRIEVAL
SYSTEM, OR TRANSMITTED, INANYFORM
OR BYANY MEANS,ELECTRONIC, ME-
CHANICAL, PHOTOCOPYING,RECORDING,
OROTHERWISEWITHOUT THE PRIOR
WRITTEN PERMISSION OF CHRYSLER
MOTORS.
To order the special service tools usedand
illustrated, please refer tothe instructions on
inside back cover.
Chrysler Motors reservesthe right tomakechangesindesignortomake
additionstoorimprovementsinitsproducts wihtout imposinganyobliga-
tionsuponitselftoinstall them onitsproductspreviouslymanufactured.
Litho in U.S.A. Copyright©1991 Chrysler Motors 20M191

FOREWORD
Theinformationcontainedinthisservicemanualhas been preparedfortheprofessionalautomotivetechni-
cian involvedindailyrepairoperations.Thismanual does notcovertheoryofoperation, which is addressed in
servicetrainingmaterial.
Information inthismanualisdividedintogroups. These groupscontaingeneralinformation,diagnosis, test-
ing, adjustments,removal,installation,disassembly,andassembly procedures forthecomponents.
To assist inlocatinga group title page, usetheGroupTabLocatoronthe following page. The solid barafter
thegroup title isalignedtoa solid tabonthe first page of each group.This first page ofthegrouphasa
contentssectionthatlistsmajortopics within thegroup.
ChryslerMotors reserves the right to change testingprocedures,specifications,diagnosis,repairmethods,or
vehicle wiring atanytimewithoutpriornoticeorincurringobligation.
Information describingtheoperationanduseofstandardandoptionalequipmentisincludedintheOwner's
Manual provided with thevehicle.

C01P01E1T AliSYSTEiINDEX
Name Group-page
5.9LDIESEL ENGINES. . ....9-1
ENGINE DIAGNOSIS 9=3
ENGINE SERVICE PROCEDURES 9-12
GENERAL INFORMATION -.9-1
AIR CONDITIONING 24-1
COMPRESSOR OVERHAUL (SD-709) ........24-1
Compressor 24-2
Compressor Isolation 24-1
Compressor ShaftSeal24-5
Cylinder Head/Valve Plate 24-8
Description 24-1
Magnetic Clutch24-2
Purging Compressor ofAir24-1
TORQUE SPECIFICATIONS—A/C
COMPRESSOR 24-9
BRAKES............ .......5-1
Diesel Vacuum Pump .5-1
Installing Vacuu,—Steering Pump
Assembly 5-5
Low Vacuum Warning Switch5-1
Pump Adapter Replacement 5-4
Removing Vacuum—Steering Pump
Assembly 5-2
Vacuum Pump Diagnosis5-2
Vacuum Pump Operation5-1
Vacuum Pump Replacement 5-4
Vacuum Pump Serviceability 5-1
COOLING SYSTEM 7-1
SPECIFICATIONS 7-1
EMISSION CONTROL SYSTEMS 25-1
EXHAUST EMISSION CONTROLS 25-1
EXHAUST SYSTEM AND INTAKE MANIFOLD. ....11-1
SERVICE PROCEDURES (DIESEL ENGINES) . . . 11-1
ExhaustManifold11-1
Intake ManifoldCover/AirIntakeHeater11-2
Intercooler .11-8
Turbocharger11-3
SPECIFICATIONS 11-9
FUEL SYSTEM 14-1
DIESEL FUEL INJECTION 14-1
Air IntakeHeaterRelays—Engine Controller
Output 14-4
Battery Voltage—Engine Controller Input... 14-2
Brake Switch—Engine Controller Input....14-2
Charge Air Temperature Sensor—Engine
Controller Input14-2
Crank Signal—Engine Controller Input14-2
Engine Controller 14-1
GeneralInformation14-1
Name Group-page
Ignition Sense—Engine Controller Input14-2
KSBSolenoid14-5
OverdriveOverride Switchitch —Engine
Controller Input14-2
OverdriveSolenoid—Engine Controller
Output 14-5'
Park/NeutralSwitch—Engine Controller
Input14-2
SCIReceiveandSCITransmit—Engine
Controller Output 14-5
Speed Control—Engine Controller Input....14-3
Speed Control—Engine Controller Output ...14-5
System Diagnosis14-1
System Operation14-5
Throttle Position Sensor(TPS)—Engine
Controller Input14-3
Vehicle Distance(Speed)Sensor—Engine
Controller Input14-3
Wait-To-Start Lamp—Engine Controller
Output 14-5
Water-ln-Fuel Lamp—Engine Controller
Output . 14-5
Water-ln-FuelSensor—Engine Controller
Input14-3
GENERAL DIAGNOSIS-DIESEL . 14-8
Air IntakeHeater14-11
KSBSolenoid14-11
On Board Diagnostics14-11
Throttle Position SensorTest14-10
Visual Inspection14-8
SERVICE PROCEDURES 14-21
Fuel Injection Pump 14-22
Injection Timing 14-26
KSBSolenoid14-22
Throttle Position Sensor14-21
INSTRUMENT PANEL AND GAUGES 8E-1
SPEED CONTROL SYSTEM 8H-1
SERVICE PROCEDURES 8H-8
TEST PROCEDURES 8H-4
Checkingfor Fault Code 8H-4
Distance (Speed)SensorTest8H-4
Inoperative System 8H-4
Road Test8H-4
Speed ControlCable Attachment—Engine ..8H-7
Speed ControlCable Attachment—Servo ...8H-7
Speed ControlSwitchTest8H-5
Speed Control System Electrical Tests8H-4
Stop Lamp Speed ControlSwitchTest....8H-5
Vacuum Supply Test8H-6

STEERING 19-1
GENERALINFORMATION19-1
TRANSMISSION21-1
Fluid TemperatureThermo-Switches 21-2
General (information 21-1
General Specifications—Diesel A518 ...... 21-3
Governor Weight Assembly 21-1
Planetary Gears — 21-1
Service Procedure And Specification
Changes 21-2
Servicing TheNew Overrunning Clutch .... 21-2
Torque Converter 21-1
Transmission And Overdrive Compounder
Clutch Packs 21-2
Transmission Case 21-1
Transmission Overrunning Clutch And
Low-Reverse Drum 21-1

GROUP TABLOCATOR
Brakes
CoolingSystem
8E
Instrument Paneland
Gauges
8H
Speed Control System
8W
Wiring Diagrams
Engines
d|i|ExhaustSystemand Intake
Manifold
14 FuelSystem
19
Steering
iH:;&"*»-.i
21 Transmission
24 Air
Conditioning
25
Emission Control Systems

•
BRAKES 5 - 1
BRAKES
DIESEL VACUUM PUMP
INSTALLING VACUUM-STEERING PUMP
ASSEMBLY
LOW VACUUM WARNING SWITCH
PUMP ADAPTER REPLACEMENT
REMOVING VACUUM-STEERING PUMP
ASSEMBLY
CONTENTS
page
1
5
1
4
VACUUM PUMP DIAGNOSIS ...
VACUUM PUMP OPERATION ..
VACUUM PUMP REPLACEMENT
VACUUM PUMP SERVICEABILITY
page
.. 2
.. 1
.. 4
.. 1
DIESEL VACUUM PUMP
A newdesignpowerbrakevacuumpump is used
on 1991-1/2ADmodels with theCumminsturbodie-
selengine.However,thenewvacuumpump is still
combined with thepowersteeringpumpinto a single
assembly(Fig.1).
Thenewvacuumpumpis a constantdisplacement,
vane-typepump.Vacuumisgeneratedbyfour vanes
mountedinthepumprotor.Therotor is locatedin
thepumphousing andis pressed onto the pump
shaft.
Thevacuumandsteeringpumpsarebothoperated
by a singledrive gear pressed ontothevacuumpump
shaft.Thedrive gear is operatedby . thecamshaft
gear.
Thevacuumandpowersteeringpumpshafts are
connectedby a coupling.Eachpumpshaft hasan
adapter with drivelugsthat engage inthecoupling.
Thevacuumpumprotatingcomponentsare lubri-
catedbyengine oil. Lubricating oilissuppliedtothe
pumpthrough an oil line at'theundersideofthe
pumphousing.
VACUUM PUMP SERVICEABILITY
Thevacuumpumpisnot a serviceablecomponent.
If diagnosisindicates a pumpmalfunction,thepump
must be removedandreplaced asan assembly.Do
not disassemble orattempttorepairthepump.
Thecombinedvacuumandsteeringpumpassembly
mustberemovedfor access toeitherpump.However,
thevacuumpumpcanberemoved without havingto
disassemble thepowersteeringpump.
If thepowersteeringpumprequiresservice,simply
remove the assemblyand separate thetwopumps.
Refer tothe pumpremovalandinstallationproce-
dures inthissection.
LOW VACUUM WARNING SWITCH
A vacuumswitch is usedtomonitoroutputofthe
vacuumpump. The switch isin circuit with the
brakewarning light.
VACUUM
GEAR ADAPTER
J9105-94
Fig. 1 Vacuum And Steering Pump Assembly
A vacuum hose connectstheswitch to thepower
brakebooster.A wire harness connectstheswitchto
thebrakewarning light.
Theswitch is mounted onthe driversideinner
fenderpaneljustbelowthehoodhinge(Fig.2).
VACUUM PUMP OPERATION
Vacuum pumpoutput is transmittedtothepower
brakeboosterthrougha supply hose. The hose iscon-
nectedtoanoutletportonthepumphousingandto
thecheckvalveinthepowerbrakebooster.
Pumpoutput ranges from a minimum of8.5to 25
inchesvacuum.
Thepumprotorand vanes arerotatedbythepump
drive gear. Thedrive gear is operatedbythecam-
shaft gear.
Boostervacuum level is monitoredby a warning
switch (Fig. 2). Theswitchconsists ofa vacuum
chamberthat measures vacuum level and a sensor in
circuit with thebrakewarning light.

5- 2 BRAKES
•
Fig. 2 Vacuum Switch Location
Thevacuumchamberisconnectedtothebooster
checkvalvebya vacuumsupply hose. A wire har-
ness connects theswitch sensor tothebrakewarning
light. Ifboostervacuumfallsbelow8.5inchesfor
8-10 seconds ormore,theswitch sensor completes
the circuit tothewarning light causingitto illumi-
nate.
VACUUM PUMP DIAGNOSIS
Vacuum pumpdiagnosisinvolvescheckingpump
output with a vacuum gauge. Thelowvacuumwarn-
ing switchcan also bechecked with a vacuum gauge.
Refertothediagnosisprocedureinthissection.
A standardvacuum gauge canbe used tocheck
pumpoutputwhen necessary. Simplydisconnectthe
pumpsupply hose andconnecta vacuum gauge to
theoutletportfortesting purposes. Vacuumshould
hold steady ina range ofapproximately8.5to25
inchesatvariousengine speeds.
DIAGNOSING LOW VACUUM OUTPUT
CONDITION
A lowboostervacuumconditionora faulty low
vacuumwarningswitch will cause thebrakewarn-
ing light to illuminate. If the light does goonandin-
dicates theexistenceofa lowvacuumcondition,
checkthevacuumpump,boosterandwarningswitch
as follows:
(1) Checkvacuumpumpoilfeed line. Verify that
line connectionsare secure andnotleaking.Ifleak-
ageisnotedandpumpisnoisy,replacepump.
(2) Checkvacuumpumpoutput with a standard
vacuum gauge. Disconnectthesupply hose tothe
booster. Connectthe gauge tothis hose andrunthe
engineatvariousthrottleopenings.Outputshould
range from 8.5to25inchesvacuum.Ifvacuumis
consistentlybelow8.5inches,theproblemis with the
vacuum hoses ora vacuumpumpcomponent.Ifout-
putis within specified limits, continuetesting.
(3) Checkboosteroperationasdescribedinthedi-
agnosis section. Replace thecheckvalve,vacuum
hoses, orbooster if necessary. However, if boosterop-
erationiscorrectbutthewarning light is still on,
continuetesting.
(4) Disconnectthevacuum hose from thewarning
switch, plugthe hose andconnecta handvacuum
pumptotheswitch.
(5) Startandruntheengine.
(6) Apply 8.5to9 inchesofvacuumtothewarning
switch and observe thewarning light. Ifthe light
goes out,theswitchvacuum hose iseitherlooseor
leaking. Ifthe light remainson,leavetheengine
running andcontinuetesting.
(7) Apply 20-25inchesvacuumtotheswitchand
observe warning light operation.Ifthe light now
goes out,theswitchisatfaultandshouldbere-
placed.Ifthe light remainson,continuetesting.
(8) Reconnectthevacuum hoses andreplacethe
original warningswitch with a knowngoodswitch.
Run theengineand observe warning light operation.
If the light isnowoff,theoldswitchis faulty. Ifthe
light remainson,theproblemisinthe wiring be-
tweentheswitchandwarning light.
REMOVING VACUUM-STEERING PUMP
ASSEMBLY
(1) Disconnectbatterynegativecable.
(2) Positiondrainpanunderpowersteeringpump.
(3) Disconnectvacuumandsteeringpump hoses
from respectivepumps(Fig.3).
Fig. 3 Vacuum And Steering Pump Hose
Connections
(4) Disconnectoil pressure sender wiresat sender
(Fig. 4).

BRAKES 5 - 3
(5) Removeoil pressure sender (Fig. 4).
PUMP ASSEMBLY
LOWER MOUNTING
STEERING
PUMP
ENGINE BLOCK
J9119-74
Fig. 4 Oil Pressure Sender Location
(6) Disconnect lubricating oilfeed line from fitting
atundersideofvacuumpump(Fig. 5).
VACUUM
PUMP
VACUUM
PUMP
OIL FEED
LINE J9105-96
Fig. S Oil Feed Line Connection At Pump
(7) Removelower bolt that attaches pumpassembly
to engineblock(Fig. 6).
(8) Removebottom,inboard nut that attaches
adapter to steeringpump (Fig. 6).Thisnut secures a
small bracket to engine block. Nutandbracketmust
beremovedbeforepumpassembly can be removed
from block.
ADAPTER
BRACKET
BOTTOM-INBOARD
ADAPTER BRACKET NUT
J9105-97
Fig. 6 Adapter And Pump Mounting Fastener
Location
(9) Removeupper bolt that attaches pump assem-
bly to engineblock(Fig. 7).
(10) Removepumpassembly from vehicle (Fig. 8).
J9119-76
Fig. 7 Removing Pump Assembly Upper Mounting
Bolt
VACUUM PUMP REPLACEMENT
(1) Removenutsattachingvacuumpump to
adapter (Fig. 8).

5 - 4 BRAKES
J9105-98
Fig, 8 Pump Assembly Removal
(2) Removevacuumpump from adapter(Fig. 9).
Turn pump gear backand forth to disengagepump
shaft from couplingif necessary.
(3) Inspectadapter O-ring (Fig.9).Replace O-ring
if cutor torn.
COUPLING
O-RING PUMP
ADAPTER
J9105-99
Fig, 9 Vacuum Pump Removed From Adapter
(4) Lubricateadapter O-ring with engineoil.
(5) Notepositionof drive slotsin coupling. Thenro-
tatedrive gear to align tangs onvacuumpumpshaft
with coupling (Fig. 10).
(6) Verify thatpump is seated inadapterandcou-
pling.
(7) Install and tightenpumpattachingnuts and
washers.
PUMP ADAPTER REPLACEMENT
(1) Removecoupling from adapter(Fig.11).
(2) Removeremainingadapterattachingnutsand
removeadapter from steeringpump(Fig.12).
(3)If steeringpump will beserviced,remove spacer
from eachinboardmountingstudonpump(Fig.12).
(4) Cleanandlubricatepumpshaft with engine oil.
ROTATE DRIVE
GEAR TO ALIGN
TANGS J9105-102
Fig. 10 Aligning Pump Shaft Drive Tangs
Fig. 11 Removing/installing Pump Drive Coupling
(5) Install spacers onsteeringpump studs (Fig. 12).
(6) Install O-ring onadapter (Fig. 11).
(7) Positionadapteronpumpstuds.
(8) Install attachingnutsonoutboardstudandon
thetwoupperpumpstuds.Do not install nut on
lower, inboardstud at this time. Tightennuts to24
N-m (18ft.lbs.)torque.
(9) Install coupling on pumpshaft. Be sure cou-
pling is securelyengagedinshaftdrivetangs.

Fig. 12 Steering Pump Mounting Stud Spacer
Locations
(10) Install vacuumpumpon adapter. Rotatedrive
gear until tangs onpumpshaft engage incoupling.
Verify thatpumpis seated before installing attach-
ing nuts.
(11) Install andtightenvacuumpumpattaching
nuts.
INSTALLING VACUUM-STEERING PUMP
ASSEMBLY
(1) Positionnewgasketonvacuumpumpmounting
flange (Fig. 13).UseMoparperfectseal,orsilicone
adhesive/sealerto hold gasketinplace.
Fig. 13 Positioning Gasket On Pump Mounting
Flange
— _ BRAKES 5 - 5
(2) Insertpumpassemblyupperattaching bolt in
mounting flange andgasket.Use sealer or grease to
hold bolt inplaceif necessary.
(3) Positionpumpassemblyonengineand install
upper bolt (Fig.14).Tightenupper bolt only enough
to hold assemblyinplaceatthis time.
Fig. 14 installing Pump Assembly On Engine
(4) Working from undervehicle, install pumpas-
semblylowerattaching bolt. Thentightenupperand
lower bolt to77N-m(57ft.lbs.)torque.
(5) Positionbracketonsteeringpumpinboardstud.
Then install remainingadapterattachingnuton
stud. Tightennutto24N»m(18ft.lbs.)torque.
(6) Connectoilfeed line tovacuumpumpconnec-
tor. Tighten line fitting securely.
(7) Install oil pressure sender andconnect sender
wires.
(8) Connectsteeringpump pressure andreturn
lines topump.Tighten pressure line fitting to30
N-m (22ft.lbs.)torque.
(9) Connectvacuum hose tovacuumpump.
(10) Connectbatterycables,ifremoved.
(11)Fill powersteeringpumpreservoir.
(12) Purgeair from steeringpumplines.Starten-
gine and slowly turn steeringwheel left and right to
circulate fluid andpurgeair from system.
(13) Stopengineandtopoffpowersteering reser-
voir fluid level.
(14) Startengineandcheckbrakeandsteeringop-
eration. Verify thatpowerbrakeboosteris providing
vacuum assist and firm brakepedalisobtained.
Then verify thatsteeringactioniscorrect.Dothis
before moving vehicle.

• COOLING SYSTEM 7 -1
COOLINGSYSTEM
GENERAL INFORMATION
This groupcontains changes made tothediesel
cooling systemduringthemid-1991modelyear.The
main change isa newhighercapacitycross-flowra-
diator. Thecoolingsystemcapacities have changed
asa resultofthenewradiator.
RADIATOR
A cross-flowradiatorisusedinthe mid-1991 model
year.Theradiatorcoolstheengineandautomatic
transmission (if equipped).
REMOVAL
(1) Disconnectbatterynegativecable from battery.
WARNING: DONOT REMOVE THECYLINDER
BLOCK DRAIN PLUGSORLOOSENTHE RADIATOR
DRAINCOCK WITH THESYSTEMHOTAND UNDER
PRESSURE BECAUSESERIOUS BURNS FROM
COOLANT CANOCCUR,
(2) Drain thecoolingsystem.Referto Draining
Cooling Systeminthe1991 Rear Wheel Drive Truck
ServiceManual.
(3) Remove hose clampsand hoses from radiator.
Removecoolant reserve tank hose from radiator filler
necknipple.
(4) Removefanshroudretainingclips.Theshroud
hastwo tabs thatfit intoclipsinthebottomofthe
radiator. Lift theshroudupandpositionitbackonto
theengine(Fig.1).
(5) Removeradiatortopmountingbrackets.The
bracketsfit oversupportdowelsontheradiator inlet
tank(Fig.1).
(6) Thebottomoftheradiatorhastwodowelsthat
fit into holesinthelowersupportpanel.Taking care
not to damage radiatorcoolingfins ortubes, lift ra-
Fig. 1 Radiator and Fan Shroud
diator straightupoutofenginecompartment.
INSTALLATION
(1) Positionshroudrearwardonengine.
(2) Lowerradiatorinto position. Thedowelsonthe
bottom oftheradiatorfit intoalignmentholesinthe
lower supportpanel.
(3) Install topmountingbrackets.Tightenmount-
ing screwsto23N»m(17in.lbs.)torque.
(4) Connectradiator hoses. Install hose clamps.
(5) Positionfanshroudonradiatorflange. Install
retaining clips.
(6) Open heater valve.
(7)Fill coolingsystem with coolant.Referto Fill-
ing CoolingSysteminthe1991 Rear Wheel Drive
Truck ServiceManual.
(8) Operateengine until it reaches normaltemper-
ature.Checkcoolingsystem.
SPECIFICATIONS
COOLING SYSTEM CAPACITIES
RADIATOR
FAN
CAPACITY
IMINI
MOML
A m
WIDTH
INCHES
IHKK-
NISS
ROWS
OF
TUBES
HNS
MR
INCH
DIAMETBR
INCHES
NO. OP
BLADES
PITCH
INCH
CLWTCH
•NOAOIMINT
T1MMRATURI
QUARTS
units
Diesel All 26 2.25 3 13 22.0
7
2.20
140°F 17.0 16.1
Diesel All • 26
2.25 3 13 22.0
7 2.20 140
°F 16.0 15.1
39107 881

•
INSTRUMENT PANEL AND GAUGES 8E - 1
INSTRUMENTPANELANDGAUGES
OWERDRIWE LOCKOUT SWITCH
REMOVAL
(1) Locatebracket holding chimemoduleandinter-
mittent wipemodule(Fig. 2).
(2) Remove 2 nuts holding bracket to instrument
panelsupport.
(3) Removeground straps andbracket.
(4) Depress lock tabs on switch and push it out of
theinstrumentpanel.
INSTALLATION
(1)Holdwiring connector in switch opening.
(2) Push switch on to wiring connector.
(3) Continue to push until switch snaps into place.
(4) Install bracket with modules. Be sure ground
straps are installed.
GROUND
COMBINATION
BUZZER
J918E-37
Fig. 1 Overdrive Lockout Switch Location
INTERMITTENT
WIPER MODULE
BRACKET
INTERMITTENT WIPER
CONTROL MODULE
J918E-36
Fig. 2 Intermittent Wiper Module Bracket

•
SPEED CONTROL SYSTEM8H- 1
SPEED CONTROLSYSTEM
CONTENTS
page
SERVICE PROCEDURES 8
GENERAL INFORMATION
The speed control system (Fig.1)iselectricallyac-
tuatedandvacuum operated. Theelectroniccontrol
isintegratedintothe engine controller,locatednext
tothebattery.Thecontrolsarelocatedonthe steer-
ing wheeland consist oftheON/OFF,RESUME/AC-
CEL and SET/DECELbuttons. The system is
designed to operate at speeds between 35 mph(50
km/h) and85mph(142km/h).
WARNING; THEUSE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
TO ACTIVATE: BypushingtheON/OFFbutton
tothe depressed latchedposition,ON,the speed con-
trol functionisnow ready foruse.
TO DEACTIVATE: A softtapofthe brake pedal,
ornormal brake applicationwhilethe system is en-
gaged will disengage speed controlwithout erasing
memory.Pushing the ON/OFFbutton totheun-
latchedpositionorturningoffthe ignition erases the
memory.
TO SETSPEED:Whenthevehicle has reached
thedesired speed push theSET/DECELbuttontoen-
gage system which will thenautomaticallymaintain
thedesired speed.
TO DECELERATE:When speed control isen-
gaged, holdingtheSET/DECELbutton depressed al-
lowsthevehicleto coast to a lower speed setting.
TO RESUME: After disengagingthe speed control
system by tapping the brake pedal push the RE-
SUME/ACCEL buttontoreturnvehicletotheprevi-
ously set speed.
TO ACCELERATE:While speed control isen-
gaged, holdtheRESUME/ACCELbutton depressed
and release ata newdesired speed. This will allow
page
TEST PROCEDURES 4
thevehicle to continuously accelerate and setata
higher speed setting.
TAP-UP: When the speed control system isen-
gaged, tappingtheRESUME/ACCELbutton will in-
crease the speed setting by2 mph (3 km/h). The
system will respond tomultiple tap-ups.
TO ACCELERATE for PASSING: Depress the
accelerator as youwouldnormally.Whenthepedal
is released thevehicle will return to the speed set-
ting inmemory.
SERVO CONNECTOR J918H-20
Fig, 1 Speed Control System

8H -2 SPEED CONTROL SYSTEM
WARNING:THEUSE Of THESPEEDCONTROL
IS NOT RECOMMENDEDWHENDRIVING
CONDITIONS DONOT PERMITMAINTAINING
ACONSTANTSPEED,SUCH AS HEAVY
TRAFFIC ORON ROADSTHATAREWINDING,
ICY,SNOWCOVERED OR SLIPPERY.
START ENGINE
ACCELERATE VEHICLE
TO DESIRED SPEED
SPEED CONTROL
ENGAGES WHEN
ENGINE IS STARTED
PUSHON/OFFBUTTON
TO "ON" POSITION.
FAULTY
ELECTRICAL CIRCUIT*
SPEED CONTROLENGAGES
WITHOUTPUSHINGTHE
"SET/DECEL" BUTTON
PUSHANDRELEASE
"SET/DECEL" BUTTON
FAULTY ELECTRICAL CIRCUIT*
j :
DEFECTIVE SERVO
DEFECTIVE SERVO
REMOVE FOOT FROM
ACCELERATOR. SPEED
SHOULDBECONTROLLED
NOSPEEDCONTROLWHEN
SET/DECEL BUTTON IS
PRESSED AND RELEASED
HUNTINGSURGE OR
SPEED VARIATIONS
ATLOWSPEEDS
FUSEBLOWN LOCK-UP
TORQUE CONVERTER
ROUGHNESS
NO VACUUM AT
SERVO
AMPLIFICATION
OF ENGINE
SURGE
SPEED CONTROL
THROTTLE CABLE
DISCONNECTED
DEFECTIVE SERVO
IMPROPER STOPLAMP
AND SPEED CONTROL
SWITCH ADJUSTMENT
DEFECTIVE
CABLE
FAULTY ELECTRICAL
CIRCUIT*
DEFECTIVE
ENGINE CONTROLLER
EXCESSIVE SAG
ONHILLS OR
INTRAILERTOWING
SPEED SETTINGAFTER
LOCK-IN, TOO HIGH
ORTOOLOW
ENGINE
PERFORAAANCE
VACUUM LEAK
VACUUM
LEAK
DEFECTIVE SERVO
EXCESSIVE LOAD MAY
REQUIRE MANUAL
ASSISTANCE ON HILLS
DEFECTIVE
CABLE
DEFECTIVE
VACUUM PUMP
DEFECTIVE
VACUUM PUMP
REFER TO GROUP 5 - BRAKES
FOR VACUUM PUMP DIAGNOSIS.
DEFECTIVE SERVO
*TESTS AND ADJUSTMENTSAREDESCRIBED
INAPPROPRIATESECTION OF SERVICE
MANUAL.
DEFECTIVE
VACUUM PUMP
J918H-27X

SPEED C01T10LSYSTEiSH - 3
ZZZ3
DRIVEVEHICLEOVER
ROUGHROAD
UNITDISENGAGES
ONROUGHROAD
IMPROPER
ADJUSTMENTOFSTOP
LAMP ANDSPEED
CONTROL SWITCH*
FAULTY
ELECTRICAL
CIRCUIT *
EfMGSNE DOES
NOT RETURN TO
NORMALIDLE
SPEEDCONTROL
THROTTLE CABLE
KINKEDORDAMAGED
STANDARD THROTTLE
LINKAGEFAULTS
NORESUME WHEN
BUTTONISPRESSED
TAP BRAI
LIGHTLY
CONTROI
DISEN
<E PEDAL
, SPEED
. SHOULD
GAGE
r
SPEED CONTROL
DISENGAGES
PUSH RESUME/ACCEL
SWITCHVEHICLE
SHOULDRESUME
PREVIOUSLY
MEMORIZEDSPEED
VEHICLE RESUMES
SPEED
DEPRESSBRAKE
PEDAL, SPEED
CONTROL
SHOULDDISENGAGE
NOSYSTEM
DISENGAGEMENT
WHEN BRAKEPEDAL
ISDEPRESSED
DEFECTIVE OR
IMPROPERLYADJUSTED
STOP LAMP AND
SPEED CONTROL
SWITCH
SPEED CONTROL
THROTTLE CABLE
KINKEDORDAMAGED
FAULTY ELECTRICAL
' CIRCUIT*
DEFECTIVE SERVO
SPEED CONTROL
DISENGAGES
DEFECTIVE SWITCH
FAULTY ELECTRICAL
CIRCUIT'
NOSYSTEM
DISENGAGE
WHEN BRAKEPEDALIS
DEPRESSED
RESUMESPEED
ISPOSSIBLE
BELOW 20 M.P.H.
DEFECTIVE ENGINE
CONTROLLER
SPEED CONTROL
SYSTEMOK
DEFECTIVE DISTANCE
SENSOR
FAULTY ELECTRICAL
CIRCUIT*
DEFECTIVE
ENGINE CONTROLLER
J918H-28X