2001 DODGE RAM stop start

When engine rpm is above idle speed, the IAC is
used for the following:
²Off-idle dashpot (throttle blade will close quickly
but idle speed will not stop quickly)
²Deceleration air flow control
²A/C compressor load control (also opens the pas-
sage slightly before the compressor is engaged so
that the engine rpm does not dip down when the
compressor engages)
²Power steering load control
The PCM can control polarity of the circuit to con-
trol direction of the stepper motor.
IAC Stepper Motor Program:The PCM is also
equipped with a memory program that records the
number of steps the IAC stepper motor most recently
advanced to during a certain set of parameters. For
example: The PCM was attempting to maintain a
1000 rpm target during a cold start-up cycle. The last
recorded number of steps for that may have been
125. That value would be recorded in the memory
cell so that the next time the PCM recognizes the
identical conditions, the PCM recalls that 125 steps
were required to maintain the target. This program
allows for greater customer satisfaction due to
greater control of engine idle.
Another function of the memory program, which
occurs when the power steering switch (if equipped),
or the A/C request circuit, requires that the IAC step-
per motor control engine rpm, is the recording of the
last targeted steps into the memory cell. The PCM
can anticipate A/C compressor loads. This is accom-
plished by delaying compressor operation for approx-
imately 0.5 seconds until the PCM moves the IAC
stepper motor to the recorded steps that were loaded
into the memory cell. Using this program helps elim-
inate idle-quality changes as loads change. Finally,
the PCM incorporates a9No-Load9engine speed lim-
iter of approximately 1800 - 2000 rpm, when it rec-
ognizes that the TPS is indicating an idle signal and
IAC motor cannot maintain engine idle.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the IAC motor through the PCM.
REMOVAL - 3.9L/5.2L/5.9L
The IAC motor is located on the back of the throt-
tle body (Fig. 32).
(1) Remove air cleaner assembly.
(2) Disconnect electrical connector from IAC motor.
(3) Remove two mounting bolts (screws) (Fig. 32).
(4) Remove IAC motor from throttle body.
REMOVAL - 8.0L
The IAC motor is located on the back of the throt-
tle body (Fig. 33).
(1) Remove the air cleaner cover.
(2) Remove the 4 air cleaner housing mounting
nuts and remove housing from throttle body.
(3) Disconnect electrical connector from IAC motor.
(4) Remove two mounting bolts (screw).
(5) Remove IAC motor from throttle body.
INSTALLATION - 3.9L/5.2L/5.9L
The IAC motor is located on the back of the throt-
tle body (Fig. 32).
Fig. 32 Mounting Bolts (Screws)ÐIAC MotorÐ3.9L/
5.2L/5.9L Engines
1 - MOUNTING SCREWS
2 - IDLE SPEED MOTOR
Fig. 33 IAC MotorÐ8.0L Engine
1 - IDLE AIR CONTROL MOTOR
2 - INTAKE MANIFOLD (UPPER HALF)
3 - THROTTLE POSITION SENSOR
4 - THROTTLE BODY
14 - 42 FUEL INJECTION - GASOLINEBR/BE
IDLE AIR CONTROL MOTOR (Continued)

STANDARD PROCEDURES - CLEANING FUEL
SYSTEM PARTS
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines and fuel injection pump.
Very tight tolerances are used with these parts. Dirt
contamination could cause rapid part wear and pos-
sible plugging of fuel injector nozzle tip holes. This
in turn could lead to possible engine misfire.
Always wash/clean any fuel system component
thoroughly before disassembly and then air dry.
Cap or cover any open part after disassembly.
Before assembly, examine each part for dirt, grease
or other contaminants and clean if necessary. When
installing new parts, lubricate them with clean
engine oil or clean diesel fuel only.
STANDARD PROCEDURE - AIR BLEED
A certain amount of air becomes trapped in the
fuel system when fuel system components on the
supply and/or high-pressure side are serviced or
replaced. Primary air bleeding is accomplished using
the electric fuel transfer (lift) pump. If the vehicle
has been allowed to run completely out of fuel, the
fuel injectors must also be bled as the fuel injection
pumpis notself-bleeding (priming).
Servicing or replacing components on the fuel
return side will not require air bleeding.
WARNING: DO NOT BLEED AIR FROM THE FUEL
SYSTEM OF A HOT ENGINE.
(1) Loosen, but do not remove, banjo bolt (test port
fitting) holding low-pressure fuel supply line to side
of fuel injection pump (Fig. 2). Place a shop towel
around banjo fitting to catch excess fuel.
The fuel transfer (lift) pump is self-priming: When
the key is first turned on (without cranking engine),
the pump operates for approximately 2 seconds and
then shuts off. The pump will also operate for up to
25 seconds after the starter is quickly engaged, and
then disengaged without allowing the engine to start.
The pump shuts off immediately if the key is on and
the engine stops running.
(2) Turn key to CRANK position and quickly
release key to ON position before engine starts. This
will operate fuel transfer pump for approximately 25
seconds.
(3) If fuel is not present at fuel supply line after
25 seconds, turn key OFF. Repeat previous step until
fuel is exiting at fuel supply line.(4) Tighten banjo bolt at fuel supply line to 24 N´m
(18 ft. lbs.) torque. Primary air bleeding is now com-
pleted.
(5) Attempt to start engine. If engine will not
start, proceed to following steps.If engine does
start, it may run erratically and be very noisy
for a few minutes. This is a normal condition.
(6)Continue to next step if:
²The vehicle fuel tank has been allowed to run
empty
²The fuel injection pump has been replaced
²High-pressure fuel lines have been replaced
²Vehicle has not been operated after an extended
period
CAUTION: Do not engage the starter motor for more
than 30 seconds at a time. Allow two minutes
between cranking intervals.
(7) Perform previous air bleeding procedure steps
using fuel transfer pump. Be sure fuel is present at
fuel supply line (Fig. 2) before proceeding.
(8) Crank the engine for 30 seconds at a time to
allow air trapped in the injection pump to vent out
the drain manifold.Fig. 2 Fuel Supply Line Banjo Bolt
1 - FUEL SUPPLY LINE
2 - FUEL RETURN LINE
3 - BANJO BOLT (TEST PORT FITTING)
4 - OVERFLOW VALVE
5 - BANJO FITTING
BR/BEFUEL DELIVERY - DIESEL 14 - 57
FUEL DELIVERY - DIESEL (Continued)

(e) Connect electrical connector to WIF sensor.
(f) Install fuel filter. Refer to previous steps.
(4)Fuel Heater Element:
(a) Do not install fuel filter until heater element
is installed.
(b) Position heater element into filter housing
(fingers downward). Lock fingers into housing.
(c) Install new o-ring to electrical connector
(where connector passes through filter housing).
Apply a light film of clean diesel oil to o-ring seal.
Press this connector into filter housing until it
snaps into heater element.
(d) Install temperature sensor housing and 2
mounting screws to fuel filter housing.
(e) Connect electrical connector.
(f) Install fuel filter. Refer to previous steps.
(5)Drain Valve:
(a) Install 2 new o-rings to valve and filter hous-
ing.
(b) Apply a light film of clean diesel oil to both
seals.
(c) Position valve to filter housing.
(d) Install 4 mounting screws and tighten to 3±5
N´m (30±40 in. lbs.) torque.
(e) Connect drain hose to drain valve.
(f) Install fuel filter. Refer to previous steps.
(6) Start engine and check for leaks.
FUEL HEATER
DESCRIPTION
The fuel heater assembly is located on the side of
the fuel filter housing (Fig. 9).
The heater/element assembly is equipped with a
temperature sensor (thermostat) that senses fuel
temperature. This sensor is attached to the fuel heat-
er/element assembly.
OPERATION
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
When the temperature is below 4568 degrees F,
the temperature sensor allows current to flow to the
heater element warming the fuel. When the temper-
ature is above 7568 degrees F, the sensor stops cur-
rent flow to the heater element.
Battery voltage to operate the fuel heater element
is supplied from the ignition switch and through the
fuel heater relay. Also refer to Fuel Heater Relay.
The fuel heater element and fuel heater relay
are not computer controlled.
The heater element operates on 12 volts, 300 watts
at 0 degrees F.
DIAGNOSIS AND TESTING - FUEL HEATER
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
NOTE: The fuel heater element, fuel heater relay
and fuel heater temperature sensor are not con-
trolled by the Powertrain Control Module (PCM).
A malfunctioning fuel heater can cause a wax
build-up in the fuel filter/water separator. Wax
build-up in the filter/separator can cause engine
starting problems and prevent the engine from rev-
ving up. It can also cause blue or white fog-like
exhaust. If the heater is not operating in cold tem-
peratures, the engine may not operate due to fuel
waxing.
The fuel heater assembly is located on the side of
the fuel filter housing (Fig. 10).
The heater assembly is equipped with a built-in
fuel temperature sensor (thermostat) that senses fuel
temperature. When fuel temperature drops below 45
degrees68 degrees F, the sensor allows current to
flow to the built-in heater element to warm the fuel.
When fuel temperature rises above 75 degrees68
degrees F, the sensor stops current flow to the heater
element (circuit is open).
Fig. 9 Fuel Heater Location
1 - FUEL HEATER AND TEMP. SENSOR
2 - FUEL FILTER/WATER SEPARATOR
3 - FUEL HEATER ELECTRICAL CONNECTOR
14 - 62 FUEL DELIVERY - DIESELBR/BE
FUEL FILTER / WATER SEPARATOR (Continued)

The transfer pump is self-priming: When the key is
first turned on (without cranking engine), the pump
will operate for approximately 2 seconds and then
shut off. The pump will also operate for up to 25 sec-
onds after the starter is engaged, and then disen-
gaged and the engine is not running. The pump
shuts off immediately if the key is on and the engine
stops running.
The fuel volume of the transfer pump will always
provide more fuel than the fuel injection pump
requires. Excess fuel is returned from the injection
pump through an overflow valve. The valve is located
on the side of the injection pump (Fig. 52). It is also
used to connect the fuel return line to the side of the
injection pump. This valve opens at approximately 97
kPa (14 psi) and returns fuel to the fuel tank
through the fuel return line.
DIAGNOSIS AND TESTING - FUEL TRANSFER
PUMP PRESSURE
The following tests will include: pressures
tests of fuel transfer pump (engine running and
engine cranking), a pressure drop test of fuel
filter, a test for supply side restrictions, and a
test for air in fuel supply side.
Fig. 50 Fuel Transfer Pump Location
1 - OIL PRESSURE SENSOR
2 - PUMP BRACKET NUTS (3)
3 - SUPPORT BRACKET BOLT
4 - BANJO BOLT (REAR)
5 - FUEL SUPPLY LINE
6 - ELECTRICAL CONNECTOR
7 - BANJO BOLT (FRONT)
8 - FUEL TRANSFER PUMP
Fig. 51 Engine Control Module (ECM) Location
1 - ENGINE CONTROL MODULE (ECM)
2 - HEX HEADED BOLT
3 - 50-WAY CONNECTOR
4 - FUEL TRANSFER PUMP
5 - MOUNTING BOLTS (3)
Fig. 52 Injection Pump Overflow Valve Location
1 - FUEL SUPPLY LINE
2 - FUEL RETURN LINE
3 - BANJO BOLT (TEST PORT FITTING)
4 - OVERFLOW VALVE
5 - BANJO FITTING
14 - 80 FUEL DELIVERY - DIESELBR/BE
FUEL TRANSFER PUMP (Continued)

WORM THRUST BEARING PRELOAD
(1) Mount the gear carefully into a vise.
CAUTION: Do not overtighten the vise on the gear
case. This may affect the adjustment
(2) Remove adjuster plug locknut (Fig. 5) .
(3) Rotate the stub shaft back and forth with a 12
point socket to drain the remaining fluid.
(4) Turn the adjuster in with Spanner Wrench
C-4381. Tighten the plug and thrust bearing in the
housing until firmly bottomed in the housing about
28-31 N´m (20-23 ft. lbs.).
(5) Place an index mark on the housing even with
one of the holes in adjuster plug (Fig. 6) .
(6) Measure back (counterclockwise) 18 mm (0.70
in) and mark the housing (Fig. 7) .
(7) Rotate adjustment cap back (counterclockwise)
with spanner wrench until hole is aligned with the
second mark (Fig. 8) .
(8) Install and tighten lock nut to 108 N´m (80 ft.
lbs.). Be sure adjustment cap does not turn while
tightening the lock nut.
PITMAN SHAFT OVER-CENTER PRELOAD
NOTE: Before performing this procedure, the worm
bearing preload adjustment must be performed.
(1) Rotate the stub shaft with a 12 point socket
from stop to stop and count the number of turns.
(2) Starting at either stop, turn the stub shaft
back 1/2 the total number of turns. This is the center
of the gear travel (Fig. 9) .(3) Place the torque wrench in the vertical position
on the stub shaft. Rotate the wrench 45 degrees each
side of the center and record the highest rotational
torque in this range (Fig. 10) . This is the Over-Cen-
ter Rotating Torque.
NOTE: The stub shaft must rotate smoothly without
sticking or binding.
Fig. 5 Adjuster Lock Nut
1 - ADJUSTER NUT
2 - STEERING GEAR
3 - LOCK NUT
4 - PUNCH
Fig. 6 Alignment Marking On Housing
1 - INDEX
Fig. 7 Second Marking On Housing
1 - REFERENCE MARK
BR/BEGEAR 19 - 17
GEAR (Continued)

NOTE: Vehicles with long return lines or oil coolers
turn wheel 40 times.
(5) Start the engine. With the engine idling main-
tain the fluid level.
(6) Lower the front wheels and let the engine idle
for two minutes.
(7) Turn the steering wheel in both direction and
verify power assist and quit operation of the pump.
If the fluid is extremely foamy or milky looking,
allow the vehicle to stand a few minutes and repeat
the procedure.
CAUTION: Do not run a vehicle with foamy fluid for
an extended period. This may cause pump damage.
STANDARD PROCEDURE - FLUSHING POWER
STEERING SYSTEM
Flushing is required when the power steering/hy-
draulic booster system fluid has become contami-
nated. Contaminated fluid in the steering/booster
system can cause seal deterioration and affect steer-
ing gear/booster spool valve operation.(1) Raise the front end of the vehicle off the
ground until the wheels are free to turn.
(2) Remove the return line from the pump.
NOTE: If vehicle is equipped with a hydraulic
booster remove both return lines from the pump.
(3) Plug the return line port/ports at the pump.
(4) Position the return line/lines into a large con-
tainer to catch the fluid.
(5) While an assistant is filling the pump reservoir
start the engine.
(6) With the engine running at idle turn the wheel
back and forth.
NOTE: Do not contact or hold the wheel against the
steering stops.
(7) Run a quart of fluid through the system then
stop the engine and install the return line/lines.
Fig. 2 Power Steering Pump
1 - CHECK OIL LEVEL; IF LEAKAGE PERSISTS WITH THE
CORRECT LEVEL AND CAP TIGHT, REPLACE THE CAP
2 - SHAFT SEAL3 - RESERVOIR O-RING
4 - O-RING SEAL
19 - 32 PUMPBR/BE
PUMP (Continued)

(8) Fill the system with fluid and perform Steering
Pump Initial Operation, (Refer to 19 - STEERING/
PUMP - STANDARD PROCEDURE).
(9) Start the engine and run it for fifteen minutes
then stop the engine.
(10) Remove the return line/lines from the pump
and plug the pump port/ports.
(11) Pour fresh fluid into the reservoir and check
the draining fluid for contamination. If the fluid is
still contaminated, disassemble and clean the steer-
ing gear and flush the system again.
(12) Install the return line/lines and perform
Steering Pump Initial Operation, (Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
REMOVAL - GASOLINE ENGINE
(1) Remove the serpentine drive belt, (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) OR (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - REMOVAL).
(2) Remove the hoses from the power steering
pump and cap the fittings.
(3) Remove battery ground cable and unthread
stud from cylinder head, do not remove from bracket.
(4) Loosen upper bracket bolt and remove the
lower bracket to engine block bolts.
(5) Pivot the pump assembly past the coolant tube.
(6) Remove the upper stud and remove upper bolt
from cylinder head.
(7) Remove steering pump and mounting bracket
from engine as an assembly.
(8) Remove the pump pulley with Puller C-4333, to
access pump attaching bolts, (Refer to 19 - STEER-
ING/PUMP/PULLEY - REMOVAL).
(9) Remove the front pump bracket (Fig. 3). On
8.0L engine remove rear pump bracket (Fig. 4).
REMOVAL - DIESEL ENGINE
(1) Remove and cap steering pump hoses and vac-
uum pump vacuum line.
(2) Remove the sender unit from engine block and
plug hole in block (Fig. 5).
(3) Remove the serpentine belt, (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove and cap the oil feed line from the bot-
tom of the vacuum pump (Fig. 6).
(5) Remove the lower bolt that attaches the vacu-
um/steering pump assembly to the engine block.
Remove the nut from the steering pump attaching
bracket (Fig. 6).
(6) Remove upper bolt from the pump assembly
(Fig. 7) and remove the assembly.
(7) Remove the mounting gasket.
(8) Remove the steering pump to vacuum pump
bracket attaching nuts (Fig. 8).
Fig. 3 Pump Mounting 8.0L
1 - FRONT BRACKET
2 - REAR BRACKET
3 - STEERING PUMP
4 - PULLEY
Fig. 4 Pump Mounting 8.0L
1 - FRONT BRACKET
2 - REAR BRACKET
3 - STEERING PUMP
4 - PULLEY
BR/BEPUMP 19 - 33
PUMP (Continued)

(c) Install springs and struts in hub (Fig. 81).
Use lots of petroleum jelly to hold them in place.
Then compress struts with your fingers and move
sleeve upward until struts are started in sleeve.
Verify that struts are engaged in sleeve before pro-
ceeding.
(d) Turn synchro assembly upright. Then move
sleeve into neutral position on hub and work struts
into sleeve at same time. Be sure struts are seated
and springs are not displaced during assembly.(6) Install first gear stop ring in 1-2 synchro hub
and sleeve (Fig. 82). Verify stop ring is seated and
engaged in hub and sleeve.
(7) Install 1-2 synchro assembly and stop ring on
mainshaft with the taper on the sleeve facing for-
ward. (Fig. 83).
(8) Install snap ring that secures 1-2 synchro on
mainshaft hub (Fig. 84). Verify snap ring is seated in
groove in mainshaft hub.
(9) Assemble second gear clutch cone, clutch ring
and stop ring (Fig. 85).
Fig. 80 1-2 Synchro Sleeve On Hub
1 - ALIGN WIDE SLOT IN SLEEVE WITH WIDE SPLINE OF HUB
2 - 1-2 SLEEVE AND HUB
Fig. 81 1-2 Synchro Struts And Springs
1 - WOOD BLOCKS
2 - HUB
3 - SLEEVE
4 - STRUTS AND SPRINGS (4 EACH)
Fig. 82 First Gear Stop Ring In Synchro Hub
Fig. 83 1-2 Synchro
1 - MAINSHAFT HUB
2 - 1-2 SYNCHRO ASSEMBLY
3 - TAPERED SIDE OF SLEEVE
21 - 70 MANUAL - NV4500BR/BE
MANUAL - NV4500 (Continued)