sensor JEEP YJ 1995 Service And Repair Manual

MULTI-PORT FUEL INJECTION (MFI)ÐCOMPONENT REMOVAL/INSTALLATION
INDEX
page page
Accelerator Pedal and Throttle Cable........... 58
Air Cleaner Element....................... 59
Air Cleaner Housing....................... 58
Air Conditioning (A/C) Clutch Relay............ 58
Automatic Shutdown (ASD) Relay............. 59
Brake Switch............................ 59
Camshaft Position Sensor................... 60
Crankshaft Position Sensor.................. 60
Engine Coolant Temperature Sensor........... 60
Fuel Filter............................... 60
Fuel Injector............................. 60
Fuel Pressure Regulator.................... 61
Fuel Pump Module........................ 61
Fuel Pump Relay......................... 61
Fuel Rail Assembly........................ 62
Fuel System Pressure Release Procedure....... 62
Fuel Tank Pressure Relief/Rollover Valve........ 62Fuel Tanks.............................. 62
Fuel Tubes/Lines/Hoses and Clamps........... 62
Idle Air Control (IAC) Motor.................. 62
Ignition Coil............................. 62
Intake Manifold........................... 63
Intake Manifold Air Temperature Sensor......... 60
Manifold Absolute Pressure (Map) Sensor....... 63
Oxygen (O2S) Sensor...................... 63
Park Neutral Switch....................... 63
Power Steering Pressure SwitchÐ2.5L
Engine Only............................ 63
Powertrain Control Module (PCM)............. 64
Quick-Connect Fittings..................... 64
Throttle Body............................ 64
Throttle Position Sensor (TPS)............... 65
Torque Converter Clutch Relay............... 65
Vehicle Speed Sensor...................... 66
ACCELERATOR PEDAL AND THROTTLE CABLE
Refer to the Accelerator Pedal and Throttle Cable
section of this group for removal/installation proce-
dures.
AIR CONDITIONING (A/C) CLUTCH RELAY
The A/C clutch relay is located in the power distri-
bution center (PDC) (Figs. 1 or 2). For location of this
relay within the PDC, refer to label on PDC cover.
AIR CLEANER HOUSING
REMOVAL
(1) Unlock clean air hose clamp (Figs. 3 or 4) at air
cleaner cover. To unlock the clamp, attach adjustablepliers to clamp and rotate pliers as shown in figure
5. Remove clean air hose at cover.
(2) Disconnect vacuum lines at air cleaner housing.
(3) YJ Models: Release the three over-center type
clamps securing the housing to the housing bracket.
XJ Models: Remove the housing cover and remove air
cleaner element. Remove two bolts and one nut.
(4) Release the air cleaner housing from the ambi-
ent air inlet and remove housing from vehicle.
INSTALLATION
(1) Position air cleaner housing to body and ambi-
ent air inlet.
(2) YJ Models: Lock the three over-center type
clamps securing the housing to the housing bracket.
XJ Models: Install two bolts and one nut to housing.
Install air cleaner element and cover.
(3) Install vacuum lines to housing.
Fig. 1 PDCÐYJ Models
Fig. 2 PDCÐXJ Models
14 - 58 FUEL SYSTEM COMPONENT REMOVAL/INSTALLATIONJ

CAMSHAFT POSITION SENSOR
For removal/installation procedures, refer to Group
8D, Ignition System. See Camshaft Position Sensor.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
The intake manifold air temperature sensor is in-
stalled into the intake manifold plenum (Figs. 7 or
8).
REMOVAL
(1) Disconnect the electrical connector from the
sensor.
(2) Remove the sensor from the intake manifold.
INSTALLATION
(1) Install the sensor into the intake manifold.
Tighten the sensor to 28 Nzm (20 ft. lbs.) torque.
(2) Connect the electrical connector to the sensor.
CRANKSHAFT POSITION SENSOR
For description, operation and removal/installation
procedures, refer to Group 8D, Ignition Systems in
this manual.
ENGINE COOLANT TEMPERATURE SENSOR
The coolant temperature sensor is installed in the
thermostat housing (Fig. 9).
REMOVAL
(1) Drain cooling system until the coolant level is
below the cylinder head. Observe theWARNINGSin
Group 7, Cooling.
(2) Disconnect the coolant temperature sensor wire
connector.
(3) Remove the sensor from the thermostat hous-
ing (Fig. 9).
INSTALLATION
(1) Install coolant temperature sensor into the cyl-
inder block. Tighten to 28 Nzm (21 ft. lbs.) torque.
(2) Connect the wire connector.
(3) Fill the cooling system. Refer to Group 7, Cool-
ing System.
FUEL FILTER
Refer to the Fuel Delivery System section of this
group for removal/installation procedures.
FUEL INJECTOR
REMOVAL
(1) Remove the fuel rail. Refer to Fuel Rail Re-
moval in this section.
(2) Remove the clip(s) that retain the fuel injec-
tor(s) to the fuel rail (Figs. 10 or 11).
INSTALLATION
(1) Install the fuel injector(s) into the fuel rail as-
sembly and install retaining clip(s).
(2) If the same injector(s) is being reinstalled, in-
stall new o-ring(s).
(3) Install fuel rail. Refer to Fuel Rail Installation
in this section.
(4) Start engine and check for fuel leaks.
Fig. 7 Sensor LocationÐ2.5L Engine
Fig. 8 Sensor LocationÐ4.0L Engine
Fig. 9 Engine Coolant Temperature SensorÐTypical
14 - 60 FUEL SYSTEM COMPONENT REMOVAL/INSTALLATIONJ

FUEL RAIL ASSEMBLY
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39 PSI).
THIS PRESSURE MUST BE RELEASED BEFORE
SERVICING THE FUEL RAIL.
(1) Remove fuel tank filler tube cap.
(2) Disconnect the negative battery cable from bat-
tery.
(3) Perform the Fuel System Pressure Release Pro-
cedure as described in the Fuel Delivery System sec-
tion of this Group.
(4) Remove and numerically attach a tag (if fuel
injector is not already tagged), the injector harness
connectors. Do this at each injector (Fig. 12).
(5) Disconnect vacuum line from fuel pressure reg-
ulator (Fig. 12).
(6) Disconnect fuel supply line from fuel rail and
the fuel return line from fuel pressure regulator (Fig.
12). Refer to Fuel Tubes/Lines/Hoses and Clamps, or
Quick-Connect Fittings. These can both be found in
the Fuel Delivery section of this group.
(7) Remove fuel rail mounting bolts.
On models with automatic transmissions, it may be
necessary to remove automatic transmission throttle
line pressure cable and bracket. This will aid in fuel
rail assembly removal.
(8) Remove fuel rail by gently rocking until all the
fuel injectors are out of the intake manifold.
INSTALLATION
(1) Position tips of all fuel injectors into the corre-
sponding injector bore in the intake manifold. Seat
injectors into manifold.
(2) Tighten fuel rail mounting bolts to 27 Nzm (20
ft. lbs.) torque.
(3) Connect injector harness connectors to appro-
priate (tagged) injector.
(4) Connect both fuel lines to fuel rail. Refer to the
Fuel Delivery section of this group for procedures.
(5) Connect vacuum supply line to fuel pressure
regulator.
(6) Install protective cap to pressure test port fit-
ting.
(7) Install fuel tank cap.
(8) Connect negative battery cable to battery.
(9) Start engine and check for fuel leaks.
FUEL SYSTEM PRESSURE RELEASE PROCEDURE
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF)
OF APPROXIMATELY 100 KPA (14.5 PSI). BEFORE
SERVICING THE FUEL PUMP, FUEL RAIL, FUELLINES, FUEL FILTER OR FUEL INJECTOR, THE
FUEL SYSTEM PRESSURE MUST BE RELEASED.
Refer to the Fuel Delivery System section of this
group. See Fuel Pressure Release procedure.
FUEL TANKS
Refer to the Fuel Tank section of this group for re-
moval/installation procedures.
FUEL TANK PRESSURE RELIEF/ROLLOVER VALVE
Refer to the Fuel Tank section of this group for re-
moval/installation procedures.
FUEL TUBES/LINES/HOSES AND CLAMPS
Refer to the Fuel Delivery System section of this
group for removal/installation procedures. Also refer
to Quick-Connect Fittings in the Fuel Delivery sec-
tion of this group.
IDLE AIR CONTROL (IAC) MOTOR
The IAC motor is mounted to the throttle body ad-
jacent to the throttle position sensor (Fig. 14).
REMOVAL
(1) Disconnect the electrical connector from the
IAC motor.
(2) Remove IAC motor torx head mounting bolts.
(3) Remove IAC motor.
INSTALLATION
(1) Install IAC motor into throttle body and
tighten retaining bolts.
(2) Connect electrical connector to IAC motor.
IGNITION COIL
Refer to Group 8D, Ignition Systems for removal/
installation procedures.
Fig. 14 Idle Air Control MotorÐRemoval/
InstallationÐTypical
14 - 62 FUEL SYSTEM COMPONENT REMOVAL/INSTALLATIONJ

INTAKE MANIFOLD
Refer to Group 11, Exhaust System and Intake
Manifold for removal/installation procedures.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor is located on the dash panel near
the rear of the engine cylinder head (valve) cover
(Fig. 15).
REMOVAL
(1) Disconnect the MAP sensor electrical connector
(Fig. 15).
(2) Disconnect the MAP sensor vacuum supply
hose (Fig. 15).
(3) Remove the MAP sensor mounting bolts and re-
move MAP sensor.
INSTALLATION
(1) Install MAP sensor to dash panel and secure
with mounting bolts.
(2) Install the MAP sensor vacuum supply hose.
(3) Connect the MAP sensor electrical connector.
OXYGEN (O2S) SENSOR
The O2S sensor is installed in the exhaust down
pipe just below the exhaust manifold flange (Fig. 16).
REMOVAL
WARNING: THE EXHAUST MANIFOLD BECOMES
VERY HOT DURING ENGINE OPERATION. ALLOW
ENGINE TO COOL BEFORE REMOVING OXYGEN
SENSOR.
(1) Raise and support the vehicle.
(2) Separate the electrical connectors.
(3) Remove the O2S sensor from the exhaust man-
ifold. Snap-On oxygen sensor wrench (number YA
8875) may be used for removal and installation.
INSTALLATION
Threads of new factory oxygen sensors are coated
with anti-seize compound to aid in removal.
(1) Install the O2S sensor into the exhaust mani-
fold and tighten to 30 Nzm (22 ft. lbs.) torque.
(2) Connect the O2S sensor wire connector to the
main harness.
(3) Lower the vehicle.
PARK NEUTRAL SWITCH
Refer to Group 21, Transmissions for park neutral
switch service.
POWER STEERING PRESSURE SWITCHÐ2.5L
ENGINE ONLY
The power steering pressure switch is installed in
the power steering high-pressure hose (Figs. 17 or
18).
REMOVAL
(1) Disconnect the electrical connector from the
power steering pressure switch.
Fig. 15 MAP SensorÐTypical
Fig. 16 Oxygen SensorÐTypical
Fig. 17 Power Steering Pressure SwitchÐYJ Models
JFUEL SYSTEM COMPONENT REMOVAL/INSTALLATION 14 - 63

(2) Place a small container or shop towel beneath
the switch to collect any excess fluid.
(3) Remove the switch.
INSTALLATION
(1) Install the power steering switch.
(2) Connect the electrical connector to the switch.
(3) Check power steering fluid and add as neces-
sary.
(4) Start the engine and again check power steer-
ing fluid. Add fluid if necessary.
POWERTRAIN CONTROL MODULE (PCM)
On XJ models, the PCM is located in the engine
compartment next to the air cleaner (Fig. 19). On YJ
models, the PCM is located in the engine compart-
ment behind the windshield washer fluid reservoir
(Fig. 20).
REMOVAL
(1) Disconnect the negative battery cable at the
battery.(2) YJ Models Only: Remove the windshield
washer fluid tank.
(3) Loosen the 60-Way connector mounting bolt
(Figs. 19 or 20).
(4) Remove the electrical connector by pulling
straight back.
(5) Remove the three PCM mounting bolts.
(6) Remove PCM.
INSTALLATION
(1) After the PCM electrical connector has been
separated from the PCM, inspect the pins for corro-
sion, being spread apart, bent or misaligned. Also in-
spect the pin heights in the connector. If the pin
heights are different, this would indicate a pin has
separated from the connector. Repair as necessary.
(2) Install PCM. Tighten three mounting bolts to 1
Nzm (9 in. lbs.) torque.
(3) Engage 60-way connector into PCM. Tighten
connector mounting bolt to 4 Nzm (35 in. lbs.) torque.
(4) YJ Models: Install windshield washer fluid
tank.
(5) Connect negative cable to battery.
QUICK-CONNECT FITTINGS
Refer to the Fuel Delivery System section of this
group for removal/installation procedures.
THROTTLE BODY
REMOVAL
(1) Disconnect the negative battery cable.
(2) Disconnect air cleaner hose from throttle body.
(3) Disconnect idle air control motor and throttle
position sensor wire connectors.
(4) Disconnect accelerator cable, throttle cable (au-
tomatic transmission) and speed control cable (if
equipped) from throttle arm (Fig. 21).
(5) Remove throttle body mounting bolts (Fig. 22),
throttle body and gasket. Discard old gasket.
Fig. 18 Power Steering Pressure SwitchÐXJ Models
Fig. 19 PCM LocationÐXJ Models
Fig. 20 PCM LocationÐYJ Models
14 - 64 FUEL SYSTEM COMPONENT REMOVAL/INSTALLATIONJ

INSTALLATION
(1) Install throttle body and new gasket. Tighten
throttle body mounting bolts to 12 Nzm (9 ft. lbs.)
torque.
(2) Connect idle air control motor and throttle po-
sition sensor wire connectors.
(3) Connect throttle linkage to throttle arm.
CAUTION: When the automatic transmission throttle
cable is connected, it MUST be adjusted.
(4) If equipped with an automatic transmission,
connect and adjust the transmission line pressure ca-
ble. Refer to Group 21, Transmissions for adjustment
procedure.
(5) Install air cleaner hose to throttle body.
(6) Connect negative battery cable to battery.
THROTTLE POSITION SENSOR (TPS)
The TPS is mounted to the throttle body (Figs. 23
or 24).
REMOVAL
(1) Disconnect TPS electrical connector.
(2) Remove TPS mounting bolts.
(3) Remove TPS.
INSTALLATION
The throttle shaft end of the throttle body slides
into a socket in the TPS (Fig. 25). The TPS must be
installed so that it can be rotated a few degrees. (If
the sensor will not rotate, install the sensor with the
throttle shaft on the other side of the socket tangs).
The TPS will be under slight tension when rotated.
(1) Install the TPS and retaining bolts.
(2) Connect TPS electrical connector to TPS.
(3) Manually operate the throttle (by hand) to
check for any TPS binding before starting the engine.
TORQUE CONVERTER CLUTCH RELAY
On YJ models, the TCC relay is located in the en-
gine compartment. It is attached to the cowl panel
with one bolt (Fig. 26). On XJ models, the TCC relay
is located in the power distribution center (PDC)
Fig. 21 Cables at Throttle Body
Fig. 22 Throttle BodyÐRemoval/InstallationÐ
Typical
Fig. 23 TPS LocationÐ2.5L Engine
Fig. 24 TPS LocationÐ4.0L Engine
JFUEL SYSTEM COMPONENT REMOVAL/INSTALLATION 14 - 65

(Fig. 27). For location of this relay within the PDC,
refer to label on PDC cover.
VEHICLE SPEED SENSOR
The vehicle speed sensor (Fig. 28) is located on the
extension housing of the transmission on 2WD mod-
els. It is located on the transfer case on 4WD models.
REMOVAL
(1) Raise and support vehicle.
(2) Disconnect the electrical connector from the
sensor.
(3) Remove the sensor mounting bolt (Fig. 29).
(4) Remove the sensor (pull straight out) from the
Fig. 25 Throttle Position SensorÐInstallation
Fig. 26 TCC Relay LocationÐYJ Models
Fig. 27 Power Distribution CenterÐXJ Models
Fig. 28 Vehicle Speed Sensor LocationÐTypical
Fig. 29 Sensor Removal/InstallationÐTypical
14 - 66 FUEL SYSTEM COMPONENT REMOVAL/INSTALLATIONJ

speedometer pinion gear adapter (Fig. 29). Do not re-
move the gear adapter from the transmission.
INSTALLATION
(1) Clean the inside of speedometer pinion gear
adapter before installing speed sensor.
(2) Install sensor into speedometer gear adapter
and install mounting bolt.Before tightening bolt,verify speed sensor is fully seated (mounted
flush) to speedometer pinion gear adapter.
(3) Tighten sensor mounting bolt to 2.2 Nzm (20 in.
lbs.) torque.
(4) Connect electrical connector to sensor.
SPECIFICATIONS
GENERAL INFORMATION
The following specifications are published from the
latest information available at the time of publica-
tion.If anything differs between the specifica-
tions found on the Vehicle Emission Control
Information (VECI) label and the following
specifications, use specifications on VECI label.
The VECI label is located in the engine compart-
ment.
FUEL TANK CAPACITIES
FUEL SYSTEM
TORQUE
JFUEL SYSTEM SPECIFICATIONS 14 - 67

POWER STEERING PUMP
INDEX
page page
Drive Pulley Replacement................... 13
Flow Control Valve Fitting O-Ring Seal......... 14
Power Steering PumpÐInitial Operation........ 15
Pressure and Return Hose Replacement........ 11Pump Replacement........................ 12
Reservoir Replacement..................... 14
Service Information........................ 11
SERVICE INFORMATION
The power steering pump internal components are
not serviced or adjusted. If a malfunction or an inter-
nal fluid leak occurs, the complete unit must be re-
placed. A reservoir, cap, and O-ring seal kit are the
only service components available.
PRESSURE AND RETURN HOSE REPLACEMENT
Cap hose open ends and pump/steering gear fit-
tings to prevent entry of foreign material.
WARNING: POWER STEERING FLUID (AND PUMP
COMPONENTS) AND THE EXHAUST SYSTEM CAN
BE EXTREMELY HOT IF THE ENGINE HAS BEEN
RECENTLY OPERATING. DO NOT START THE EN-
GINE WITH ANY LOOSE OR DISCONNECTED
HOSES. DO NOT ALLOW THE HOSES TO TOUCH A
HOT EXHAUST MANIFOLD OR THE CATALYTIC
CONVERTER.
REMOVAL
(1) Remove fasteners from hose retaining brackets
at all locations.
(2) If applicable, remove pressure sensor from
pressure hose (Fig. 1, 2).
(3) Disconnect pressure and return hose from the
steering gear. Drain the fluid from pump and reser-
voir (Fig. 1, 2, 3).
(4) Disconnect pressure and return hose from the
pump. Remove hoses from vehicle (Fig. 1, 2, 3).
INSTALLATION
(1) Wipe hose ends, pump and gear unions clean.
(2) Connect hose at steering gear and pump. Route
hose while avoiding extreme bends or kinks.The
hose must be kept away from exhaust system
components.Do not distort hose tube ends by bend-
ing, kinking or over tightening.
(3) If applicable, install and tighten pressure sen-
sor to 28 Nzm (252 in. lbs.) torque (Fig. 1, 2).
(4) When used, the protective foam sleeves must be
properly positioned on the hose to prevent chafing.
Fig. 1 Power Steering HoseÐYJ
JSTEERING 19 - 11

(7) Disconnect transfer case shift linkage at trans-
fer case.
(8) Disconnect vehicle speed sensor wires and
transfer case vent hose.
(9) Remove slave cylinder from clutch housing.
(10) Disconnect transmission shift lever as follows:
(a) Lower transmission-transfer case assembly
approximately 7-8 cm (3 in.) for access to shift le-
ver.
(b) Reach up and around transmission case and
unseat shift lever dust boot from transmission shift
tower (Fig. 6). Move boot upward on shift lever for
access to retainer that secures lever in shift tower.
(c) Reach up and around transmission case and
press shift lever retainer downward with your fin-
gers. Turn retainer counterclockwise to release it.
(d) Lift lever and retainer out of shift tower (Fig.
6).Do not remove the shift lever from the
floorpan boots. Leave the lever in place for
later transmission installation.
(11) Mark front and rear propeller shafts for in-
stallation alignment (Fig. 7). Then remove both
shafts.
(12) Remove crankshaft position position sensor
(Figs. 8, 9).
CAUTION: It is important that the crankshaft posi-
tion sensor be removed prior to transmission re-
moval. The sensor can easily be damaged if left in
place during removal operations.
(13) Unclip wire harnesses from transmission and
transfer case.
(14) Remove slave cylinder from clutch housing.
(15) Support transmission with transmission jack.
(16) Remove nuts attaching transfer case to trans-
mission and remove transfer case.
(17) Secure transmission to jack with safety
chains.
(18) Remove clutch housing brace rod.(19) Remove clutch housing-to-engine bolts.
(20) Pull transmission jack rearward until input
shaft clears clutch. Then slide transmission out from
under vehicle.
Fig. 6 Removing/Installing Shift Lever
Fig. 7 Marking Propeller Shaft And Axle Yokes
Fig. 8 Crankshaft Position Sensor (2.5L)
Fig. 9 Crankshaft Position Sensor (4.0L)
21 - 4 AX 4/5 MANUAL TRANSMISSIONJ