compression ratio DODGE RAM 1999 Service User Guide
Page 1189 of 1691
Ram Pickup, Ram Van & Ram Wagon ........... (2) .............. ( 2)
Town & Country
3.3L & 3.8L ............................. ( 2) .............. ( 2)
Voyager
2.4L
A/C & Generator ...................... 190 (86) ...... 115 (52\
)
Power Steering ....................... 140 (64) ....... 90 (41\
)
3.0L
A/C .................................. 150 (68) ....... 80 (36\
)
Generator & Power Steering ............. ( 2) .............. ( 2)
3.3L .................................... ( 2) .............. ( 2)
( 1) - Used belt is a belt that has been in service for more than 15
minutes.
( 2) - Automatic belt tensioner is used. Belt tension adjustment is not
required.
\
\
\
\
\
\
\
MECHANICAL CHECKS
ENGINE COMPRESSION
Ensure battery is fully charged. Warm engine to normal
operating temperature. Disconnect wire at ignition coil to prevent
engine from starting. Check engine compression with all spark plugs
removed and throttle wide open.
COMPRESSION SPECIFICATIONS
\
\
\
\
\
\
\
Application Specification
Compression Ratio
Caravan
2.4L ...................................................... 9.4:1
3.0L ...................................................... 8.9:1
3.3L ...................................................... 8.9:1
3.8L ...................................................... 9.6:1
Dakota & Durango ........................................... 9.1:1
Ram Pickup
3.9L, 5.2L & 5.9L (Gasoline) .............................. 9.1:1\
5.9L (Diesel) ............................................ 17.5:1\
8.0L ...................................................... 8.4:1
Ram Van & Ram Wagon ........................................ 9.1:1
Town & Country
3.3L ...................................................... 8.9:1
3.8L ...................................................... 9.6:1
Voyager
2.4L ...................................................... 9.4:1
3.0L ...................................................... 8.9:1
3.3L ...................................................... 8.9:1
Normal Compression Pressure
Caravan
2.4L ............................. 170-225 psi (11.9-15.7 kg/cm
)
3.0L ...................................... 178 psi (12.5 kg/cm)
3.3L & 3.8L ................................................. ( 1)
Dakota
2.5L .............................. 120-150 psi (8.4-10.5 kg/cm
)
3.9L, 5.2L & 5.9L ........................................... ( 1)
Durango ...................................................... ( 1)
Ram Pickup, Ram Van & Ram Wagon .............................. ( 1)
Town & Country ............................................... ( 1)
Voyager
Page 1190 of 1691
2.4L ............................. 170-225 psi (11.9-15.7 kg/cm)
3.0L ...................................... 178 psi (12.5 kg/cm)
3.3L ........................................................ ( 1)
Minimum Compression Pressure
Caravan, Town & Country, & Voyager .......... 100 psi (7.0 kg/cm
)
Dakota
2.5L ........................................................ ( 1)
3.9L, 5.2L & 5.9L .......................... 100 psi (7.0 kg/cm
)
Durango ..................................... 100 psi (7.0 kg/cm)
Ram Pickup
3.9L, 5.2L & 5.9L (Gasoline) & 8.0L ........ 100 psi (7.0 kg/cm
)
5.9L (Diesel) ............................................... ( 1)
Ram Van & Ram Wagon ......................... 100 psi (7.0 kg/cm
)
Maximum Variation Between Cylinders
Caravan, Town & Country & Voyager ..................... 25 Percent
Dakota
2.5L ........................................ 30 psi (2.1 kg/cm
)
3.9L, 5.2L & 5.9L ........................................... ( 1)
Durango ...................................................... ( 1)
Ram Pickup, Ram Van & Ram Wagon .............................. ( 1)
( 1) - Information is not available from manufacturer.
\
\
\
\
\
\
\
VALVE CLEARANCE
Gasoline Models
All engines are equipped with hydraulic lifters. No
adjustments are required.
5.9L Diesel (Ram Pickup)
Valve adjustment is recommended every 150 months or 150,000
miles during normal service, every 135,000 miles during severe
service. Severe service is described as frequent short trip operation
of less than 5 miles, long periods of engine idling, trailer towing,
police, taxi, local delivery service, or operating in dusty or
excessively hot conditions. See VALVE CLEARANCE SPECIFICATIONS
(DIESEL) table.
VALVE CLEARANCE SPECIFICATIONS (DIESEL) ( 1)
\
\
\
\
\
\
\
Application In. (mm)\
Intake Valve ............................................ .010 (.25)\
Exhaust Valve ........................................... .020 (.51)\
(1) - Adjust valves with engine temperature less than 140
F (60C). \
\
\
\
\
\
\
IGNITION SYSTEM
IGNITION COIL
IGNITION COIL RESISTANCE - Ohms @ 70-80F (21-27C) \
\
\
\
\
\
\
Application Primary Secondary
Caravan
2.4L
Diamond ( 1)( 2) ............... .53-.65 .......... 11,500-13,500
Weastec ( 1) .................. .45-.65 .......... 10,900-14,700
3.0L ............................. ( 3) ..................... ( 3)
Page 1472 of 1691
converter lock-up. ECM uses various input signals such as transmission
temperature, output shaft speed, central module timer, engine speed,
APPS and brake switch position to determine operation of transmission
torque converter clutch solenoid. Transmission torque converter clutch
solenoid is located on transmission valve body.
FUEL SYSTEM
FUEL DELIVERY
Fuel Injection Pump
A camshaft-driven Bosch VP44 in-line fuel injection pump is
used to supply high pressure fuel to each fuel injector in precise
metered amounts at the correct time. See Fig. 2. The pump is timed to
camshaft gear. Pump output is controlled by integral Fuel Pump Control
Module (FPCM). Because of electronic control, idle speeds and pump
timing are not adjustable. See ON-VEHICLE ADJUSTMENTS - TRUCKS -
DIESEL article. FPCM can operate engine if crankshaft position sensor
signal does not exist. Fuel injection occurs near completion of
compression stroke for each cylinder.
Fuel injection pump contains an overflow valve which allows
excess fuel to return to the fuel tank. Overflow valve is located on
side of fuel injection pump and is used to attach the fuel return line
to the fuel injection pump.
Fuel Transfer Pump
Fuel transfer pump is located on driver's side of cylinder
block, above starter. See Fig. 2. A 12 volt, 12-amp electric vane-type
pump supplies low fuel pressure from fuel tank, through fuel
heater/fuel filter/water separator to fuel injection pump. Fuel
transfer pump contains internal check valves to prevent fuel from
bleeding back into fuel tank during engine shutdown. Pump will self
prime with ignition on for 2 seconds. Pump has 2 modes, 100 percent
duty cycle (10 psi) when engine is running and 25 percent duty cycle
(7 psi) when engine is cranking.
Fuel Filter/Water Separator
Fuel filter/water separator, located on left side of engine,
protects injection pump by removing water and contaminants from fuel.
See Fig. 2 . Assembly also includes fuel heater and Water-In-Fuel (WIF)
sensor.
In-Tank Fuel Filter
A separate in-tank fuel filter is attached to bottom of fuel
tank module. In-tank fuel filter does not require service under normal
conditions.
FUEL CONTROL
Fuel Injector
Fuel injector delivers atomized fuel into the cylinder.
During fuel injection, fuel pressure from fuel injection pump
increases to fuel injector opening pressure or pop pressure of 4500
psi (316 kg/cm
). This is the pressure required to lift fuel injector
needle valve from its seat, allowing fuel to be injected into the
cylinder. Once fuel pressure decreases to less then the opening
pressure, a spring forces needle valve closed and stops fuel injection
into the cylinders. Each fuel injector is connected to injection pump
by a high pressure (as much as 17,405 psi) line.
Fuel Injection Timing
Pump output is controlled by integral Fuel Pump Control
Page 1484 of 1691
various switch input operations to adjust IAC motor to obtain optimum
idle conditions. Deceleration stall is prevented by increasing airflow
when throttle is closed suddenly.
IGNITION SYSTEM
NOTE: Pickup equipped with 8.0L engine uses Distributorless
Ignition system (DIS). All other models use a Hall Effect
ignition system.
The PCM completely controls ignition system. During
crank/start mode, PCM will set a fixed amount of spark advance for an
efficient engine start. Amount of spark advance or retard is
determined by inputs that PCM receives from ECT sensor, engine vacuum
and engine RPM. During engine operation, PCM can supply an infinite
number of advance curves to ensure proper engine operation.
DISTRIBUTORLESS IGNITION SYSTEM (DIS)
DIS eliminates mechanical ignition components that can wear
out. PCM has complete ignition control and uses a coil pack, CMP
sensor and CKP sensor to control ignition timing. CMP sensor reads
slots in cam timing sprocket. PCM uses this information along with
information from CKP sensor to determine if fuel injectors and
ignition coils are properly sequenced for correct cylinders.
Basic timing is determined by CKP sensor position and is not
adjustable. One complete engine revolution may be required for PCM to
determine crankshaft position during cranking.
Molded ignition coils are used. Each coil fires 2 paired
spark plugs at the same time. One cylinder is on compression stroke
and other cylinder is on exhaust stroke.
HALL EFFECT IGNITION SYSTEM
This system is equipped with a Hall Effect distributor. See
Fig. 1 . Shutter(s) attached to distributor shaft rotate through
distributor Hall Effect switch, also referred to as a CMP sensor,
which contains a distributor pick-up (a Hall Effect device and
magnet). As shutter blade(s) pass through pick-up, magnetic field is
interrupted and voltage is toggled between high and low. PCM uses this
cylinder position data from CMP sensor, along with engine speed (RPM)
and CKP sensor data, to control ignition timing and injector pulse
width to maintain optimum driveability.
EMISSION SYSTEMS
Vehicles are equipped with different combinations of emission
system components. Not all components are used on all models. To
determine component usage on a specific model, see EMISSION
APPLICATIONS - TRUCKS article.
AIR INJECTION SYSTEM
This system adds a controlled amount of air to exhaust gases,
through air relief valve and check valves, to assist oxidation of
hydrocarbons and carbon monoxide in exhaust stream. Air is injected at
catalytic converters.
CRANKCASE VENTILATION (CCV) SYSTEM
CCV system performs same function as a conventional Positive