open gas tank JEEP CHEROKEE 1988 Service Repair Manual
[x] Cancel search | Manufacturer: JEEP, Model Year: 1988, Model line: CHEROKEE, Model: JEEP CHEROKEE 1988Pages: 1378, PDF Size: 19.9 MB
Page 734 of 1378
Terminal burned, affecting
performance ............ A ........... (2) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
( 1) - Refer to manufacturer's diagnostic trouble code
procedure and require repair or replacement of affected
component(s).
( 2) - Determine cause and correct prior to repair or
replacement of part.
( 3) - Determine source of contamination, such as engine coolant,
fuel, metal particles, or water. Require repair or
replacement.
( 4) - Includes inoperative, intermittent operation, failure to
perform all functions, or out of OEM specification.
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POWERTRAIN CONTROL PROM
See POWERTRAIN CONTROL MODULES (PCM) AND PROM .
PRESSURIZED EXPANSION TANK CAPS
See RADIATOR CAPS AND PRESSURIZED EXPANSION TANK CAPS .
RADIATOR CAPS AND PRESSURIZED EXPANSION TANK CAPS
RADIATOR CAP AND PRESSURIZED EXPANSION TANK CAP INSPECTION \
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Condition Code Procedure
Application incorrect ... B ........... Require replacement.
Coolant recovery check
valve inoperative ...... A ....... ( 1) Require replacement.
Fails to maintain proper
pressure ............... B ........... Require replacement.
Gasket missing .......... C . Require replacement of gasket.
Missing ................. C ........... Require replacement.
Seal missing ............ C ... Require replacement of seal.
( 1) - Inoperative includes intermittent operation or out of
OEM specification.
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RADIATOR FAN BLADES
Page 792 of 1378
Electric roller type fuel pump is located in fuel tank.
Integral check valve is used to maintain pressure in fuel delivery
system after pump stops running. Fuel pump operation is controlled by
ECU through a fuel pump relay.
IDLE SPEED ACTUATOR (ISA) MOTOR
ISA motor acts as movable idle stop to change throttle stop
angle. Both engine idle speed and deceleration throttle stop angle
are set by ISA. ECU controls ISA motor by providing appropriate
voltage outputs to produce idle speed or throttle stop angle required
for engine operating condition.
OXYGEN (O2) SENSOR
Oxygen sensor is equipped with a heating element that keeps
sensor at proper operating temperature at all times. Oxygen sensor is
located in exhaust pipe.
Maintaining proper sensor temperature at all times, system
enters "Closed Loop" operation sooner and remains in "Closed Loop"
during periods of extended idle. Electrical feed to oxygen sensor is
through ignition switch.
The ECU receives sensor voltage signal which varies with
oxygen content in exhaust gas. Signal is used by ECU as reference for
setting air/fuel mixture ratio. ECU varies voltage to injector both
to compensate for battery voltage fluctuations and to change duration
of injector opening for control of air/fuel mixture.
MANIFOLD AIR/FUEL TEMPERATURE (MAT) SENSOR
MAT sensor provides a signal to ECU that changes depending
upon temperature of air/fuel mixture in intake manifold. During high
temperature conditions, ECU will compensate for changes in density of
air.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
MAP sensor measures absolute pressure in intake manifold.
Both mixture density and ambient barometric pressure are supplied to
ECU by MAP sensor. Sensor is mounted in middle of firewall in engine
compartment. Sensor receives manifold pressure information through
vacuum line from throttle body. See Fig. 1.
Fig. 1: Manifold Absolute Pressure (MAP) Sensor
Courtesy of Chrysler Motors.
COOLANT TEMPERATURE SENSOR (CTS)
Page 1245 of 1378
Air in fuel system Bleed air from system
Incorrect or contaminated Replace fuel
fuel
Injector nozzle malfunction Check nozzles, see
FUEL SYSTEMS
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Engines Starts Injection pump timing Reset pump timing, see
and Idles Rough incorrect FUEL SYSTEMS
W/out Smoke or Engine not fully broken in Put more miles on
Noise, But Clears engine
After Warm-Up Air in system Bleed air from system
Injector nozzle malfunction Check nozzles, see
FUEL SYSTEMS
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Engine Idles Blocked fuel filter Replace fuel filter
Correctly, Injection pump timing Reset pump timing, see
Misfires Above incorrect FUEL SYSTEMS
Idle Incorrect or contaminated Replace fuel
fuel
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Engine Won't Fast idle adjustment Reset fast idle, see
Return To Idle incorrect TUNE-UP
Internal injection pump Replace injection pump,
malfunction see FUEL SYSTEMS
External linkage binding Check linkage and
remove binding
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Fuel Leaks On Loose or broken fuel line Check lines and
Ground connections
Internal injection pump Replace injection pump,
seal leak see FUEL SYSTEMS
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Cylinder Injector nozzles sticking Test injectors, see
Knocking Noise open FUEL SYSTEMS
Very low nozzle opening Test injectors and/or
pressure replace
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Loss of Engine Restricted air intake Remove restriction
Power EGR valve malfunction Replace EGR valve
Blocked or damaged exhaust Remove restriction
system and/or replace
components
Blocked fuel tank filter Replace filter
Restricted fuel filter Remove restriction
and/or replace filter
Block vent in gas cap Remove restriction
and/or replace cap
Tank-to-injection pump fuel Check fuel lines and
supply blocked connections
Blocked fuel return system Remove restriction
Incorrect or contaminated Replace fuel
fuel
Blocked injector nozzles Check nozzle for
blockage, see FUEL
SYSTEMS
Low compression Check valves, rings,
pistons, see ENGINES
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Loud Engine Basic timing incorrect Reset timing, see
Noise With Black FUEL SYSTEMS
Smoke EGR valve malfunction Replace EGR valve
Internal injection pump Replace injection pump,
malfunction see FUEL SYSTEMS