1999 DODGE RAM Fuel pressure

multiple engine sensors have failed, repair ground between splice and
PCM.
12) Connect jumper wire between OPS connector terminals. If
oil pressure warning indicator illuminates, replace OPS. If oil
pressure warning indicator does not illuminate, go to next step.
13) Do not remove jumper wire. Disconnect PCM Black connector
C2. PCM is located in engine compartment on right inner fender. Using
an external ohmmeter, measure resistance between ground and PCM White
connector C2 terminal No. 23 (Gray/Orange wire). If resistance is less\
than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open
Gray/Orange wire.
14) Check cooling system operation. If cooling system is
operating properly, go to next step. If cooling system is not
operating properly, repair engine cooling problem.
15) Using scan tool, select PCM MONITOR under SYSTEM TESTS.
If scan tool displays PCM ACTIVE ON BUS, system is currently
functioning properly. If scan tool does not display PCM ACTIVE ON BUS,
go to appropriate VEHICLE COMMUNICATIONS article.
16) Using scan tool, select MODULE ENGINE CONTROLLER. Read
PCM DTCs. If scan tool displays any charging system related DTCs, go
to appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE section
and repair DTC as necessary. If scan tool does not display any
charging system related DTCs, go to next step.
17) Check charging system operation. If charging system is
operating properly, replace instrument cluster. If charging system is
not operating properly, repair engine charging problem.
18) Using scan tool, select BODY COMPUTER MONITORS. Read CCD
BUS ENGINE INFO. If scan tool displays engine RPM, replace instrument
cluster. If scan tool does not display engine RPM, replace PCM.
OVERHEAD CONSOLE CONCERNS
AVERAGE MPH/FUEL ECON INOPERATIVE OR WRONG (CMTC FAILS TO
RESPOND TO INSTRUMENT CLUSTER DIMMING, DISTANCE TO EMPTY
INOPERATIVE OR WRONG, ELAPSED TIME INOPERATIVE/WRONG, SWITCH
ON CMTC INOPERATIVE, TRIP ODOMETER INOPERATIVE/WRONG)
NOTE: If any listed symptoms exist, Compass Mini-Trip computer
(CMTC) is defective. Replace CMTC. Perform VERIFICATION TEST
VER- 1A after each repair.
CMTC SHOWS FAILED
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
Using scan tool, perform AUTO SELF TEST. If CMTC shows
failed, replace CMTC. If CMTC does not show failed, system is
currently functioning properly.
CMTC SEGMENTS FAIL TO LIGHT UP
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
Using scan tool, perform AUTO SELF TEST. If CMTC segments
fail to illuminate, replace CMTC. If CMTC segments all illuminate
properly, system is currently functioning properly.
INCORRECT READING BEYOND +/- 5

(8) - One used on vehicles with light-duty emissions. Two used on 

vehicles with heavy-duty emissions. 

(
9) - Used on vehicles with heavy-duty emissions. 

(
10 ) - Two catalytic converters are required. 

(
11 ) - Four sensors used on vehicles with medium-duty emissions. 

Two sensors used on vehicles with heavy-duty emissions. 










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ABBREVIATIONS
ABBREVIATION DEFINITIONS








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Abbreviation Definition
AIH ................................... Air Intake Heaters
AIH-TS ............................ AIH Temperature Sensor
AP ............................. Air Pump Injection System
AP-CKV .................................... AP Check Valve
AP-RV .................................... AP Relief Valve
BP/EGR ........................... Backpressure EGR System
BP/EGR-BPT ................ BP/EGR Backpressure Transducer
CCV ................................ Crankcase Ventilation
CEC ......................... Computerized Engine Controls
CNG ............................... Compressed Natural Gas
EFI ............................ Electronic Fuel Injection
EGR-CKV .................................. EGR Check Valve
EVAP ............................. Fuel Evaporative System
EVAP-CVV ........................ EVAP Canister Vent Valve
EVAP-LDP ........................ EVAP Leak Detection Pump
EVAP-LDPF ................ EVAP Leak Detection Pump Filter
EVAP-PRRV ............ EVAP Pressure Relief Rollover Valve
EVAP-PSOL ............................ EVAP Purge Solenoid
EVAP-VC .............................. EVAP Vapor Canister
EVAP-VV ........................... EVAP Ventilation Valve
FR ................................... Fillpipe Restrictor
HO2S ................................ Heated Oxygen Sensor
MIL .......................... Malfunction Indicator Light
PCV ....................... Positive Crankcase Ventilation
SFI .................. Sequential Multiport Fuel Injection
SPK ....................................... Spark Controls
SPK-CC ........................... SPK Computer Controlled
TWC ........................ Three-Way Catalytic Converter









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Fig. 3: Typical Thermostatic Air Cleaner System
FUEL EVAPORATIVE SYSTEM (EVAP)
The EVAP system allows for proper fuel system ventilation
while preventing fuel vapors from reaching the atmosphere. This means
that vapors must be caught and stored while the engine is off, which
is when most fuel evaporation occurs. When the engine is started,
these fuel vapors can be removed from storage and burned. In most
systems, storage is provided by an activated charcoal (or carbon)
canister. See Fig. 4. On a few early systems, charcoal canisters are
not used. Instead, fuel vapors are vented into the PCV system and
stored inside the crankcase.
The main components of a fuel evaporation system are a sealed
fuel tank, a liquid-vapor separator and vent lines to a vapor-storing
canister filled with activated charcoal. The filler cap is normally
not vented to the atmosphere, but is fitted with a valve to allow both
pressure and vacuum relief.
Although a few variations do exist between manufacturers,
basic operation is the same for all systems. Check for presence of
vapor storage canister or crankcase storage connections when required.
Ensure required hoses, solenoids, etc., are present and connected
properly. Check for proper type fuel tank cap. Check for any non-OEM
or auxiliary fuel tanks for compliance and the required number of
evaporation canisters.

TROUBLE SHOOTING
NOTE: To trouble shoot mechanical engine components, see
appropriate table in TROUBLE SHOOTING article in GENERAL
INFORMATION.
REMOVAL & INSTALLATION
CAUTION: When battery is disconnected, vehicle computer and memory
systems may lose memory data. Driveability problems may exist
until computer systems have completed a relearn cycle. See
COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION
before disconnecting battery.
NOTE: For installation reference, label all electrical connectors,
vacuum hoses and fuel lines before removal. Also place mating
marks on engine hood and other major assemblies before
removal.
FUEL PRESSURE RELEASE
CAUTION: Fuel system is under pressure. Pressure must be released
before servicing fuel system components.
Gasoline
1) Disconnect negative battery cable. Loosen fuel tank cap to
release tank pressure. Press on filler tube flap to relieve any
additional tank pressure.
NOTE: Fuel filler tube has spring-loaded flap located below fuel
fill cap to serve as secondary seal if fuel fill cap is not
tightened. It is part of EVAP monitor system when vehicle is
equipped with leak detection pump (LDP). Vehicle may be
equipped with flap installed into fuel filler tube even if
vehicle is NOT equipped with LDP and EVAP monitor system.
2) Remove fuel pump relay from Power Distribution Center
(PDC). For location of relay, refer to label on underside of PDC
cover. Start and run engine until it stalls. Attempt restarting engine
until it will no longer run.
3) Unplug connector from an injector. Attach one end of a
jumper wire (18 gauge or smaller) with alligator clips to either
injector terminal. Connect other end of jumper wire to positive side
of battery. Connect one end of a second jumper wire to remaining
injector terminal.
WARNING: Powering an injector for more than a few seconds will
permanently damage injector.
4) Touch other end of second jumper wire to negative terminal
of battery for no more than a few seconds. Place a rag below fuel
line. Disconnect quick-connect fitting at fuel rail. See FUEL LINE
DISCONNECT FITTINGS. Return fuel pump relay to PDC.
Compressed Natural Gas Fuel Tube Purging (5.2L)
1) Close control valve (clockwise) on all fuel cylinders.
Open manual shutoff valve (open when handle is parallel to fuel
tubes).
2) Start and operate engine until it runs out of fuel.
Attempt 3 more engine starts. If check valve or fuel fill receptacle

is to be serviced, slowly loosen inlet side of fuel fill tube fitting
at check valve. It is normal for approximately 25 psi of residual
natural gas pressure to flow from loosened fitting. At this point, all
fuel tubes are purged of natural gas between fuel cylinders and
engine. It is now okay to open fuel system.
WARNING: Fuel cylinders still contain high-pressure fuel.
Compressed Natural Gas Fuel Cylinder Purging (5.2L)
1) Open manual shutoff valve. Open only fuel control valve(s)\
(counterclockwise) on fuel cylinder(s) to be serviced. Close all oth\
er
control valve(s) (clockwise) on fuel cylinder(s) not being service\
d.
2) Start and operate engine until it runs out of fuel.
Attempt 3 more engine starts. At this point, all fuel tubes and opened
cylinders are purged of natural gas between fuel cylinders and engine.
It is now okay to open fuel system.
WARNING: Fuel cylinders not being serviced still contain high-pressure
fuel.
FUEL LINE DISCONNECT FITTINGS
Removal & Installation (Tab Type Fitting)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect negative battery cable. Ensure area around fuel line and
disconnect fitting is clean. Place shop towel around fuel line.
2) On 2-tab connectors, squeeze retainer tabs together and
pull fuel tube/quick-connect fitting assembly off of fuel tube nipple.
On single-tab connectors, use screwdriver to pry up pull tab. See
Fig. 1 . Raise pull tab until it separates from quick-connect fitting.
Discard old pull tab. Disconnect quick-connect fitting from fuel line.
CAUTION: DO NOT install a quick-connect fitting without retainer being
either in fuel tube or already in quick-connect fitting.
After installing fuel line in disconnect fitting, pull on
fuel line and disconnect fitting to ensure fuel line is
locked in place.
3) To install, coat fuel tube nipple with clean 30W engine
oil. Insert quick-connect fitting into fuel tube until stop on fuel
tube rests against back of quick-connect fitting.
4) On single-tab connectors, obtain NEW pull tab. Push tab
down until it locks into quick-connect fitting. On 2-tab connectors,
firmly pull on fuel tube and fitting to ensure retainer and quick-
connect fitting are locked.
Removal & Installation (Retainer Type Fitting)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect negative battery cable. Ensure area around fuel line and
disconnect fitting is clean. Place shop towel around fuel line.
2) Pull backward on disconnect fitting while depressing
plastic ring into disconnect fitting. See Fig. 2. Separate fuel line
from disconnect fitting.
NOTE: Plastic retainer ring must be pressed squarely into fitting
body. If retainer is cocked during removal, it may be
difficult to disconnect fitting. Use open-end wrench on
shoulder of plastic retainer to ease disconnection.
3) To install, ensure plastic ring is in outward position
(away from disconnect fitting). If plastic ring is in inward position
(toward disconnect fitting), disconnect fitting must be replaced.
4) Lubricate end of fuel line with 30W engine oil. Insert

Fig. 2: Identifying Retainer Type Fuel Line Disconnect Fittings
Courtesy of Chrysler Corp.
ENGINE
Removal (Ram Van/Wagon)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect negative battery cable. Drain cooling system and engine
oil. Remove and discard oil filter.
2) Remove engine cover, air cleaner and oil dipstick.
Discharge A/C system (if equipped) using approved refrigerant
recovery/recycling equipment. Disconnect A/C lines at condenser, and
plug openings. Remove A/C compressor. Disconnect fan shroud.
3) Remove front bumper, grille and support brace. Disconnect
coolant hoses. Remove radiator, condenser and support as an assembly.
4) Remove upper fan shroud. Remove power steering pump with
hoses attached, and set aside. Remove air pump, spark plug wires and
distributor cap. Disconnect necessary electrical wiring, coolant hoses
and vacuum hoses. Disconnect fuel lines. See FUEL LINE DISCONNECT

FITTINGS. Remove air cleaner, throttle body, drive belts, generator,
fan and fan pulley. Remove lower fan shroud.
CAUTION: When removing engine, DO NOT lift engine by intake manifold.
5) Remove intake manifold. See INTAKE MANIFOLD. Raise and
support vehicle. Remove starter. Remove exhaust pipe and heat shields.
Disconnect transmission shift linkage. Remove crank sensor.
6) On A/T models, remove transmission inspection cover. Mark
torque converter-to-flexplate position for installation reference.
Remove torque converter-to-flexplate bolts. On M/T models, disconnect
clutch release mechanism at clutch housing.
7) Attach engine hoist to cylinder heads (at intake manifold
flanges). On all models, support transmission using a floor jack.
Remove transmission or clutch housing-to-cylinder block bolts. Remove
engine mount bolts. Remove engine out front of vehicle.
Installation
To install, reverse removal procedure. Tighten bolts/nuts to
specification. See TORQUE SPECIFICATIONS table. On A/T models, ensure
reference marks on torque converter and flexplate are aligned.
Evacuate and charge A/C system.
Removal ( Dakota 2WD, Durango 2WD, Grand Cherokee & Ram
Pickup)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect and remove battery. On all except Pickup, scribe hood
hinges for installation reference and remove hood.
2) On all models, drain cooling system. Disconnect coolant
hoses. Remove radiator, fan and shroud. Discharge A/C system (if
equipped) using approved refrigerant recovery/recycling equipment.
Disconnect A/C lines, and plug openings. On Pickup, remove upper core
support, transmission cooler and A/C condenser. On all models, remove
belt, air cleaner, vacuum lines, distributor cap and wiring.
3) Disconnect necessary electrical wiring. Disconnect fuel
lines. See FUEL LINE DISCONNECT FITTINGS. Remove throttle body and
linkage. Remove intake manifold. Remove starter, generator, charcoal
canister and horns. Disconnect power steering hoses (if equipped).
Raise and support vehicle. Drain oil. Disconnect exhaust pipe at
exhaust manifold.
4) On A/T models, remove transmission housing inspection
plate. Mark torque converter-to-flexplate position for installation
reference. Remove torque converter-to-flexplate bolts. Remove bracket
for transmission cooler lines.
NOTE: It may be necessary to remove manual transmission if
transmission cannot be supported using floor jack.
5) On M/T models, disconnect clutch release mechanism at
clutch housing. On all models, support transmission using a floor
jack. Remove transmission or clutch housing-to-cylinder block bolts.
Install engine lifting fixture, and attach chain.
CAUTION: When removing engine, DO NOT lift engine by intake manifold.
6) On Ram Pickup and Grand Cherokee, remove front engine
mount bolts. Remove engine from vehicle. On Dakota 2WD and Durango 2WD
models, remove front engine mount through-bolts. See Fig. 3. Remove
engine from vehicle.
Installation
To install, reverse removal procedure. Tighten bolts/nuts to
specification. See TORQUE SPECIFICATIONS table. On A/T models, ensure

reference marks on torque converter and flexplate are aligned.
Evacuate and charge A/C system.
Removal (Durango 4WD & Dakota 4WD)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect and remove battery. Scribe hood hinges for installation
reference and remove hood.
2) Drain cooling system. Disconnect coolant hoses. Remove
radiator, fan and shroud. Discharge A/C system (if equipped) using
approved refrigerant recovery/recycling equipment. Disconnect A/C
lines, and plug openings. Remove air cleaner, vacuum lines,
distributor cap and wiring.
3) Disconnect necessary electrical wiring. Disconnect fuel
lines. See FUEL LINE DISCONNECT FITTINGS. Disconnect accelerator
linkage. Remove throttle body. Remove starter and generator.
Disconnect power steering hoses. Raise and support vehicle. Drain oil.
Disconnect exhaust pipe at exhaust manifold.
NOTE: Engine, transmission and front axle are connected and
supported with insulators and brackets. See Fig. 3.
4) On left side, remove 2 bolts attaching differential pinion
nose bracket-to-bellhousing bolts. Remove pinion nose bracket-to-
adapter bolts (located on top of differential, near pinion). Separate
engine from engine mount by removing engine mount through-bolt and nut
located on top of engine mount.
5) On right side, remove 2 axle-to-bracket bolts and bracket-
to-bellhousing bolt. Separate engine from engine mount by removing
engine mount through-bolt and nut located on top of engine mount.
Remove engine from vehicle.