engine overheat DODGE RAM 1999 Service Repair Manual

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Pages: 1691, PDF Size: 40.34 MB

Page 43 of 1691

DODGE RAM 1999 Service Repair Manual HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* In

HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* Inoperative cooling fan.
* Faulty expansion valve.
* Refrigerant system overcharged.
* Air in refrigerant system.
* Engine overheating.
LOW SIDE PRESSURE IS HIGH & HIGH SIDE PRESSURE IS LOW
Some possible causes of low side system pressure being too
high and high side system pressure being too low include:
* Compressor belt is slipping.
* Fixed orifice tube not installed.
* Faulty compressor.
LOW SIDE PRESSURE IS LOW & HIGH SIDE PRESSURE IS HIGH
Some possible causes of low side system pressure being too
low and high side system pressure being too high include:
* Restricted refrigerant flow through refrigerant lines.
* Restricted refrigerant flow through expansion valve.
* Restricted refrigerant flow through fixed orifice tube.
* Restricted refrigerant flow through receiver-drier.
* Restricted refrigerant flow through condenser.
BLOWER MOTOR DIAGNOSIS
BLOWER MOTOR INOPERATIVE
Some possible causes of an inoperative blower motor include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor ground circuit wire harness or
connector.
* Faulty blower motor resistor.
* Faulty blower motor relay.
* Faulty blower motor switch.
* Faulty A/C-heater mode control switch.
* Faulty blower motor.
BLOWER NOT OPERATING IN ALL SPEEDS
Possible causes of the blower not operating in all speeds
include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor relay.
* Faulty blower motor resistor.
* Faulty blower motor switch.

Page 119 of 1691

Page 150 of 1691

DODGE RAM 1999 Service Repair Manual evaporator inlet line and "O" rings with refrigerant oil. Lubricate
orifice tube and "O" ring with refrigerant oil. Insert orifice tube
into evaporator inlet line with short screen toward condenser.

evaporator inlet line and "O" rings with refrigerant oil. Lubricate
orifice tube and "O" ring with refrigerant oil. Insert orifice tube
into evaporator inlet line with short screen toward condenser.
2) Tighten liquid line nut to 18 ft. lbs. (24 N.m). To
complete installation, reverse removal procedure. Evacuate, charge,
and test system for proper operation.
Removal ("F" Body)
Discharge A/C system, using approved recovery/recycling
equipment. Disconnect negative battery cable. Disconnect A/C pressure
switch connector. Use a backup wrench to hold evaporator fitting, and
loosen evaporator liquid line fitting. Remove bolt. Disconnect
evaporator liquid line. Remove and discard "O" rings. Using needle-
nose pliers, remove orifice tube from evaporator inlet line.
Installation
1) Clean evaporator line fitting with refrigerant oil. Coat
inside of inlet line and evaporator line "O" rings with refrigerant
oil. Lubricate orifice tube and "O" ring with refrigerant oil and
insert them into inlet line. Insert orifice tube into evaporator inlet
line with long screen inlet end toward condenser.
2) Tighten bolt to 12 ft. lbs. (16 N.m). Tighten evaporator
line fitting to 28 ft. lbs. (38 N.m). To complete installation,
reverse removal procedure. Evacuate, charge, and test system for
proper operation.
Removal ("J" & "N" Body)
1) Locate orifice tube. See ORIFICE TUBE LOCATION &
REMOVER/INSTALLER APPLICATION table. Discharge A/C system, using
approved recovery/recycling equipment. On "J" body, remove upper
closeout panel. On "N" body, raise and support vehicle. On all models,
disconnect condenser-to-evaporator line at condenser outlet and
discard "O" rings.
2) Disconnect condenser-to-evaporator line clip on right side
body rail, behind engine mount. Remove orifice tube using Orifice Tube
Remover/Installer (J-26549-E) or needle-nose pliers.
3) If difficulty is encountered during removal of a plugged
or restricted orifice tube, remove as much residue as possible. Using
a heat gun, carefully apply heat 1/4" from dimples on condenser inlet
line. Be careful not to overheat line.
4) If A/C pressure switch is located near orifice tube,
remove switch to protect it from heat. While heat is being applied,
grip orifice tube using orifice tube remover/installer or needle-nose
pliers. Use a turning motion along with a push-pull motion to loosen
and remove orifice tube.
Installation
1) Coat inside of condenser inlet line and "O" rings with
refrigerant oil. Lubricate orifice tube "O" ring with refrigerant oil
and insert into condenser inlet line. Insert orifice tube into
condenser inlet line with shorter screen toward evaporator.
2) Connect condenser-to-evaporator line clip on right side
body rail. Lubricate "O" rings and connect condenser inlet line.
Tighten condenser inlet line nut to 12 ft. lbs. (16 N.m). Install
closeout panel. Evacuate, charge, and test system for proper
operation.
Removal ("W" Body)
1) Locate orifice tube. See ORIFICE TUBE LOCATION &
REMOVER/INSTALLER APPLICATION table. Remove air cleaner and duct
assembly. Discharge A/C system, using approved recovery/recycling
equipment. Disconnect negative battery cable. Disconnect ABS modulator
and A/C pressure sensor/fan switch electrical connectors.

Page 460 of 1691

DODGE RAM 1999 Service Repair Manual 1) On drive shafts greater than 30" in length, measure runout
3" from transmission flange/yoke, center bearing yoke and pinion
flange using dial indicator. Maximum runout for Ram Pickup is .0

1) On drive shafts greater than 30" in length, measure runout
3" from transmission flange/yoke, center bearing yoke and pinion
flange using dial indicator. Maximum runout for Ram Pickup is .030" (.
76 mm) at front and rear end of drive shaft and .035" (.89 mm) at
center of drive shaft. Maximum runout for all other models is .010" (.
25 mm) at front and rear end of drive shaft and .015" (.38 mm) at
center of drive shaft.
2) For drive shafts less than 30" in length, maximum runout
for Pickup is .030" (.76 mm). Maximum runout for all other models is .\
020" (.51 mm). Replace drive shaft if maximum runout is exceeded.
BALANCING DRIVE SHAFT
1) Perform following procedure only after inspecting all
other possible causes of vibration. See INSPECTION. Drive shaft
imbalance may often be cured by disconnecting shaft, rotating it 180
degrees and reconnecting shaft to flange. Test drive to check results.
NOTE: DO NOT run engine for prolonged periods without forced
airflow across radiator. Engine or transmission may
overheat.
2) To balance drive shaft(s), begin by raising rear wheels
off ground and turning drive shaft with engine. Balance testing may be
done by marking drive shaft in 4 positions, 90 degrees apart around
shaft. Place marks about 6" forward of rear flange/yoke weld. Number
marks 1-4.
3) Install large diameter screw-type hose clamp around drive
shaft so clamp's head is in No. 1 position. Spin drive shaft with
engine and note vibrations. If there is little or no change in
vibration intensity, move clamp head to No. 2 position, and repeat
test.
4) Continue procedure until vibration is at lowest level. If
no difference is noted with clamp head moved to all 4 positions,
vibrations may not be due to drive shaft imbalance.
5) If vibration decreases but is not completely eliminated,
place a second clamp at same position, and repeat test. Combined
weight of both clamps in one position may increase vibration. If so,
rotate clamps 1/2" apart, above and below lowest vibration level
position, and repeat test.
6) Continue to rotate clamps, as necessary, until vibration
is at lowest point. If vibration can be eliminated or reduced to
acceptable level, bend back slack end of clamp so screw cannot loosen.
If vibration level is still unacceptable, leave rear clamp(s) in
place, and repeat procedure at front end of drive shaft. Road test
vehicle. On 4WD models, perform procedure on each shaft.
CHECKING VERTICAL ANGLE
One-Piece Drive Shafts
1) Raise and support vehicle so rear wheels can be rotated.
Rotate drive shaft so a pinion flange bearing cap faces downward.
Attach Inclinometer (C-4224) magnet to bearing cap, and measure drive
shaft vertical angle. See Fig. 4. Remove inclinometer.
2) Rotate drive shaft 90 degrees until drive shaft rear yoke
bearing cap faces downward. Attach inclinometer magnet to bearing cap,
and measure drive shaft vertical angle. Difference between 2 measured
angles is drive shaft rear angle. See Fig. 5. Remove inclinometer.
3) Rotate drive shaft until a slip joint yoke bearing cap
faces downward. Attach inclinometer magnet to bearing cap, and note
angle. Remove inclinometer. Rotate drive shaft 90 degrees until drive
shaft front yoke bearing cap faces downward. Attach inclinometer
magnet to bearing cap, and note angle. Remove inclinometer.

Page 647 of 1691

DODGE RAM 1999 Service Repair Manual CAUTION: After removing fan clutch assembly, DO NOT store fan clutch
with rear of shaft pointing downward. Silicone fluid from fan
clutch may drain into fan drive bearing, causing lu

Page 745 of 1691

DODGE RAM 1999 Service Repair Manual (1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Determine source of contamination, such as engine
coolant, fuel, metal particles, or water. Require
r

(1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Determine source of contamination, such as engine
coolant, fuel, metal particles, or water. Require
repair or replacement.
( 3) - Inoperative includes intermittent operation or out of
OEM specification. Some components may be serviceable;
check for accepted cleaning procedure.
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ENGINE COOLING SYSTEMS
NOTE: Overheating, poor engine performance, and insufficient
cabin heat can be affected by, but are not limited to,
all of the components in the engine cooling system.
ENGINE COVERS (OIL PAN, VALVE COVER, TIMING COVER)
ENGINE COVER (OIL PAN, VALVE COVER, TIMING COVER) INSPECTION\
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Condition Code Procedure
Attaching hardware
incorrect .............. B ............ Require replacement.
Attaching hardware
loose .................. A .. Require repair or replacement.
Attaching hardware
missing ................ C ............ Require replacement.
Baffle loose ............ 2 .. Suggest repair or replacement.
Baffle missing .......... C ............ Require replacement.
Bent, affecting
performance ............ A .. Require repair or replacement.
Bent, not affecting
performance ............ .. ....... No service suggested or
required.
Cracked (not leaking) ... 2 .. Suggest repair or replacement.
Leaking externally ...... A .. Require repair or replacement.
Leaking internally,
causing fluid
contamination .......... A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Restricted passage ...... A .. Require repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
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ENGINE OIL
ENGINE OIL INSPECTION\
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Condition Code Procedure
Contaminated ............ A .. ( 1) Require replacement of oil
and filter.
Level high .............. B ... Determine source of incorrect
level and require repair.
Level low ............... B ... Determine source of incorrect
level and require repair.
Maintenance intervals ... 3 ... Suggest replacement to comply
with vehicle's OEM recommended
service intervals.
( 1) - Determine source of contamination, such as engine coolant,
fuel, metal particles, or water when changing oil. Require

Page 895 of 1691

DODGE RAM 1999 Service Repair Manual CAUTION: If fuel contamination due to fungi or other microorganisms is
suspected a fuel additive with a biocide may be used. Follow
the manufacturers dosage as recommended on product

CAUTION: If fuel contamination due to fungi or other microorganisms is
suspected a fuel additive with a biocide may be used. Follow
the manufacturers dosage as recommended on product label. Use
biocides ONLY when necessary, excessive use can may cause
other fuel system problems.
DIESEL FUEL CONTAMINATION
WARNING: Diesel fuel system may be contaminated with fungi or other
microorganisms. Keep contaminated fuel away from open skin
cuts or sores to prevent skin irritation or infection.
DIESEL FUEL REQUIREMENTS
CAUTION: All diesel engines have been developed to take advantage of
the high energy content of No. 2 diesel fuel or No. 2
climatized-diesel fuels. It also operates on No. 1-diesel
fuels if temperatures are expected to be extended arctic
conditions -10
\bF (-23\bC).
WARNING: Do NOT use alcohol or gasoline as a fuel blending agent. They
can be unstable under certain conditions and hazardous or
explosive when mixed with diesel fuel.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
WARNING: Many solid state electrical components can be damaged by
static electricity (ESD). Some will display a warning label,
but many will not. Discharge personal static electricity by
touching a metal ground point on the vehicle prior to
servicing any ESD sensitive component.
ENGINE OIL
CAUTION: Never use non-detergent or straight mineral oil.
ENGINE OIL FILTER (CARTRIDGE TYPE)
CAUTION: Use of Mopar Oil Filter Cartridge (P/N 04746914) is
RECOMMENDED. The engine oil filter cartridge should be
changed at every engine oil change. Use the same type oil
that will be used in the engine.
FUEL SYSTEM SERVICE
WARNING: Relieve fuel system pressure prior to servicing any fuel
system component (fuel injection models).
HALOGEN BULBS
WARNING: Halogen bulbs contain pressurized gas which may explode if
overheated. DO NOT touch glass portion of bulb with bare
hands. Eye protection should be worn when handling or working
around halogen bulbs.
RADIATOR CAP
CAUTION: Always disconnect the fan motor when working near the
radiator fan. The fan is temperature controlled and could
start at any time even when the ignition key is in the OFF
position. DO NOT loosen or remove radiator cap when cooling
system is hot.

Page 1544 of 1691

DODGE RAM 1999 Service Repair Manual 3800 engines were suffering from exactly this. The point is that a
lack of detail could cause misdiagnosis.
As you might have guessed, a lab scope would not miss this.
RELATIONSHIP BETWEEN DW

3800 engines were suffering from exactly this. The point is that a
lack of detail could cause misdiagnosis.
As you might have guessed, a lab scope would not miss this.
RELATIONSHIP BETWEEN DWELL & DUTY CYCLE READINGS TABLE (1)
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Dwell Meter (2) Duty Cycle Meter
1
.................................................... 1%
15 .................................................. 25%
30 .................................................. 50%
45 .................................................. 75%
60 ................................................. 100%
( 1) - These are just some examples for your understanding.
It is okay to fill in the gaps.
( 2) - Dwell meter on the six-cylinder scale.
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THE TWO TYPES OF INJECTOR DRIVERS
OVERVIEW
There are two types of transistor driver circuits used to
operate electric fuel injectors: voltage controlled and current
controlled. The voltage controlled type is sometimes called a
"saturated switch" driver, while the current controlled type is
sometimes known as a "peak and hold" driver.
The basic difference between the two is the total resistance
of the injector circuit. Roughly speaking, if a particular leg in an
injector circuit has total resistance of 12 or more ohms, a voltage
control driver is used. If less than 12 ohms, a current control driver
is used.
It is a question of what is going to do the job of limiting
the current flow in the injector circuit; the inherent "high"
resistance in the injector circuit, or the transistor driver. Without
some form of control, the current flow through the injector would
cause the solenoid coil to overheat and result in a damaged injector.
VOLTAGE CONTROLLED CIRCUIT ("SATURATED SWITCH")
The voltage controlled driver inside the computer operates
much like a simple switch because it does not need to worry about
limiting current flow. Recall, this driver typically requires injector
circuits with a total leg resistance of 12 or more ohms.
The driver is either ON, closing/completing the circuit
(eliminating the voltage-drop), or OFF, opening the circuit (causing \
a
total voltage drop).
Some manufacturers call it a "saturated switch" driver. This
is because when switched ON, the driver allows the magnetic field in
the injector to build to saturation. This is the same "saturation"
property that you are familiar with for an ignition coil.
There are two ways "high" resistance can be built into an
injector circuit to limit current flow. One method uses an external
solenoid resistor and a low resistance injector, while the other uses
a high resistance injector without the solenoid resistor. See the left
side of Fig. 1.
In terms of injection opening time, the external resistor
voltage controlled circuit is somewhat faster than the voltage
controlled high resistance injector circuit. The trend, however, seems
to be moving toward use of this latter type of circuit due to its
lower cost and reliability. The ECU can compensate for slower opening