Chrysler RG Voyager. Manual — part 977
opposite preset limit or switch point. The process
then repeats itself in the opposite direction.
Short term fuel correction will keep increasing or
decreasing
injector
pulse-width
based
upon
the
upstream O2 Sensor input. The maximum range of
authority for short term memory is 25% (+/-) of base
pulse-width. Short term is violated and is lost when
ignition is turned OFF.
Long Term
The second fuel correction program is the long
term adaptive memory. In order to maintain correct
emission throughout all operating ranges of the
engine, a cell structure based on engine rpm and load
(MAP) is used.
Ther number of cells varies upon the driving con-
ditions. Two cells are used only during idle, based
upon TPS and Park/Neutral switch inputs. There
may be two other cells used for deceleration, based
on TPS, engine rpm, and vehicle speed. The other
twelve cells represent a manifold pressure and an
rpm range. Six of the cells are high rpm and the
other six are low rpm. Each of these cells has a spe-
cific MAP voltage range Typical Adaptive Memory
Fuel Cells.
As the engine enters one of these cells the PCM
looks at the amount of short term correction being
used. Because the goal is to keep short term at 0 (O2
Sensor switching at 0.5 volt), long term will update
in the same direction as short term correction was
moving to bring the short term back to 0. Once short
term is back at 0, this long term correction factor is
stored in memory.
The values stored in long term adaptive memory
are used for all operating conditions, including open
loop and cold starting. However, the updating of the
long term memory occurs after the engine has
exceeded approximately 170°-190° F, with fuel control
in closed loop and two minutes of engine run time.
This is done to prevent any transitional temperature
or start-up compensations from corrupting long term
fuel correction.
Long term adaptive memory can change the pulse-
width by as much as 25%, which means it can correct
for all of short term. It is possible to have a problem
that would drive long term to 25% and short term to
another 25% for a total change of 50% away from
base pulse-width calculation.
TYPICAL ADAPTIVE MEMORY FUEL CELLS
Open
Throttle
Open
Throttle
Open
Throttle
Open
Throttle
Open
Throttle
Open
Throttle
Idle
Decel
Vacuum
20
17
13
9
5
0
Above 1,984
rpm
1
3
5
7
9
11
13 Drive
15
Below 1,984
rpm
0
2
4
6
8
10
12
Neutral
14
MAP volt =
0
1.4
2.0
2.6
3.3
3.9
Fuel Correction Diagnostics
There are two fuel correction diagnostic routines:
• Fuel System Rich
• Fuel System Lean
A DTC is set and the MIL is illuminated if the
PCM detects either of these conditions. This is deter-
mined based on total fuel correction, short term
times long term.
PROGRAMMABLE COMMUNICATIONS
INTERFACE (PCI) BUS
DESCRIPTION
The Programmable Communication Interface Mul-
tiplex system (PCI Bus) consist of a single wire. The
Body Control Module (BCM) acts as a splice to con-
nect each module and the Data Link Connector
(DLC) together. Each module is wired in parallel to
the data bus through its PCI chip set and uses its
ground as the bus reference. The wiring is a mini-
mum 20 gage wire.
OPERATION
Various modules exchange information through a
communications port called the PCI Bus. The Power-
train Control Module (PCM) transmits the Malfunc-
tion Indicator Lamp (Check Engine) On/Off signal
and engine RPM on the PCI Bus. The PCM receives
the Air Conditioning select input, transaxle gear
position inputs over the PCI Bus. The PCM also
receives the air conditioning evaporator temperature
signal from the PCI Bus.
RS
FUEL INJECTION
14 - 25
FUEL INJECTION (Continued)
The following components access or send informa-
tion on the PCI Bus.
• Instrument Panel
• Body Control Module
• Air Bag System Diagnostic Module
• Full ATC Display Head (if equipped)
• ABS Module
• Transmission Control Module
• Powertrain Control Module
• Travel Module
• SKIM
SYSTEM DIAGNOSIS
OPERATION
The PCM can test many of its own input and out-
put circuits. If the PCM senses a fault in a major
system, the PCM stores a Diagnostic Trouble Code
(DTC) in memory.
For DTC information see On-Board Diagnostics
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/POWERTRAIN CONTROL MOD-
ULE - DESCRIPTION) .
SPECIFICATIONS
TORQUE
DESCRIPTION
N·m
Ft. Lbs.
In. Lbs.
MAP SENSOR PLASTIC
MANIFOLD
1.7
15
MAP SENSOR
ALUMINUM MANIFOLD
3.3
30
POWER STEERING
RESERVOIR PLASTIC
MANIFOLD
5.7
50
POWER STEERING
RESERVOIR ALUMINUM
MANIFOLD
11.9
105
THROTTLE CABLE
BRACKET PLASTIC
MANIFOLD
5.7
50
THROTTLE CABLE
BRACKET ALUMINUM
MANIFOLD
11.9
105
EGR TUBE PLASTIC
MANIFOLD
5.7
50
EGR TUBE ALUMINUM
MANIFOLD
11.9
105
THROTTLE BODY BOLTS
2.4L
28
20.65
250 ±50
THROTTLE BODY BOLTS
3.3/3.8L
11.8
8.7
105 ±20
O2 Sensors
27
20
The composite manifolds uses special Plastic screws. The factory installed Plastic screws can be removed and
installed up to 5 times. Do not exceed the specified torque. These screws must be installed slowly (less than 600
rpms) to avoid melting the parent material. There are service repair screws avialable for repair. They require a
higher torque than the original screws..
14 - 26
FUEL INJECTION
RS
FUEL INJECTION (Continued)
SPECIAL TOOLS
FUEL
Pressure Gauge Assembly C–4799–B
Fuel Pressure Test Adapter 6539
Spanner Wrench 6856
LOCKRING REMOVER/INSTALLER #9340
Fuel Line Adapter 1/4
O2S (Oxygen Sensor) Remover/Installer—C-4907
O2S (Oxygen Sensor) Remover/Installer - 8439
RS
FUEL INJECTION
14 - 27
FUEL INJECTION (Continued)
ACCELERATOR PEDAL
REMOVAL
(1) Hold the throttle body throttle lever in the
wide open position. Remove the throttle cable from
the throttle body cam (Fig. 1).
(2) From inside the vehicle, hold up the pedal and
remove the cable retainer and throttle cable from the
upper end of the pedal lever (Fig. 2).
(3) Remove nuts from accelerator pedal attaching
studs. Remove assembly from vehicle (Fig. 3).
INSTALLATION
(1) Position accelerator pedal assembly on dash
panel. Install retaining nuts. Tighten retaining nuts
to 12 N·m (105 in. lbs.) torque (Fig. 3).
(2) From inside the vehicle, hold up the pedal and
install the throttle cable and cable retainer in the
upper end of the pedal lever (Fig. 2).
(3) From the engine compartment, hold the throt-
tle body lever in the wide open position and install
the throttle cable (Fig. 1).
Fig. 1 THROTTLE CABLE RELEASE
Fig. 2 CABLE CLIP AND GROMMET
1 - Retainer Clip
2 - Grommet
3 - Cable Assembly
4 - Cable Retainer
5 - Dash Panel
6 - Grommet
Fig. 3 ACCELERATOR PEDAL AND THROTTLE
CABLE
1 - Grommet
2 - Cable
3 - Pedal Shaft and Bracket
4 - Seal
5 - Dash Panel
6 - Cable Assembly
14 - 28
FUEL INJECTION
RS
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