lock CHEVROLET DYNASTY 1993 Service Manual

FUEL PRESSURE REGULATOR
The pressure regulator is a mechanical device lo-
cated on the fuel rail, downstream of the fuel injec-
tors (Fig. 20). The regulator maintains a constant
328 kPa (47.6 psi) across the fuel injector tip. The regulator contains a spring loaded rubber dia-
phragm that covers the fuel return port. When the
fuel pump is operating, fuel flows past the injectors
into the regulator. Fuel is restricted from flowing
any further by the blocked return port. When fuel
pressure reaches 328 kPa (47.6 psi) it pushes on the
diaphragm, compresses the spring, and uncovers the
fuel return port. The diaphragm and spring con-
stantly move from an open to closed position to keep
the fuel pressure constant.
Fig. 20 Fuel Pressure Regulator
14 - 124 FUEL SYSTEMS Ä

(23) Check Power Brake Booster and Speed Con-
nections (Figs. 13 and 14).
(24) Inspect engine harness to main harness con-
nections. (25) Check all automatic transaxle electrical con-
nections (Fig. 15). (26) Check the vehicle speed sensor electrical con-
nection (Fig. 16). (27) Inspect the PCM 60-way electrical connector
for damage or spread terminals. Verify the 60-way
connector is fully inserted into the socket of the
PCM. Ensure wires are not stretched or pulled out of
the connector (Figs. 17, 18, and 19).
Fig. 13 Power Brake Booster and Speed Control Vacuum Hose Connections (Without Anti-lock Brakes)
Fig. 14 Speed Control Vacuum Hose Connection(With Anti-lock Brakes)
Fig. 15 Automatic Transaxle Electrical Connections
Fig. 16 Vehicle Speed Sensor Electrical Connector
Fig. 17 PCMÐAA Body
14 - 128 FUEL SYSTEMS Ä

SYSTEM TESTS
WARNING: APPLY PARKING BRAKE AND/OR BLOCK
WHEELS BEFORE PERFORMING ANY TEST ON AN
OPERATING ENGINE.
OBTAINING DIAGNOSTIC TROUBLE CODES
(1) Connect DRBII scan tool to the data link connec-
tor located in the engine compartment near the pow-
ertrain control module (PCM). (2) Start the engine if possible, cycle the transaxle
selector and the A/Cswitch if applicable. Shut off the
engine. (3) Turn the ignition switch on, access Read Fault
Screen. Record all the fault messages shown on the
DRBII scan tool. Observe the malfunction indicator
lamp (Check Engine lamp on the instrument panel).
The lamp should light for 3 seconds then go out (bulb
check). Diagnostic trouble code erasure; access erase
diagnostic trouble code data
STATE DISPLAY TEST MODE
The switch inputs used by the powertrain control
module (PCM) have only two recognized states, HIGH
and LOW. For this reason, the PCM cannot recognize
the difference between a selected switch position ver-
sus an open circuit, a short circuit, or a defective
switch. If the change is displayed, it can be assumed
that the entire switch circuit to the PCM is functional.
From the state display screen access either State
Display Inputs and Outputs or State Display Sensors.
STATE DISPLAY INPUTS AND OUTPUTS
Connect the DRBII scan tool to the vehicle. Access
the State Display screen. Then access Inputs and
Outputs. The following is a list of the engine control
system functions accessible through the Inputs and
Outputs screen. Park/Neutral Switch
Speed Control Resume
Brake Switch
Speed Control On/Off
Speed Control Set
A/C Switch Sense
S/C Vent Solenoid
S/C Vacuum Solenoid
A/C Clutch Relay
EGR Solenoid
Auto Shutdown Relay
Radiator Fan Relay
Purge Solenoid
Torque Converter Clutch Solenoid
Malfunction Indicator Lamp (Check Engine Lamp)
STATE DISPLAY SENSORS
Connect the DRBII scan tool to the vehicle and ac-
cess the State Display screen. Then access Sensor
Display. The following is a list of the engine control
system functions accessible through the Sensor Dis-
play screen. Battery Temperature
Oxygen Sensor Signal
Engine Coolant Temperature
Engine Coolant Temp Sensor
Throttle Position
Minimum Throttle
Battery Voltage
MAP Sensor Reading
Idle Air Control Motor Position
Adaptive Fuel Factor
Barometric Pressure
Min Airflow Idle Speed
Engine Speed
Fault #1 Key-On Info
Module Spark Advance
Speed Control Target
Fault #2 Key-on Info
Fault #3 Key-on Info
Speed Control Status
Speed Control Switch Voltage
Charging System Goal
Theft Alarm Status
Map Sensor Voltage
Vehicle Speed
Oxygen Sensor State
MAP Gauge Reading
Throttle Opening (percentage)
Total Spark Advance
CIRCUIT ACTUATION TEST MODE
The circuit actuation test mode checks for proper
operation of output circuits or devices which the pow-
ertrain control module (PCM) cannot internally rec-
ognize. The PCM can attempt to activate these
outputs and allow an observer to verify proper oper-
ation. Most of the tests provide an audible or visual
indication of device operation (click of relay contacts,
spray fuel, etc.). Except for intermittent conditions, if
a device functions properly during testing, assume
the device, its associated wiring, and driver circuit
working correctly.
OBTAINING CIRCUIT ACTUATION TEST
Connect the DRBII scan tool to the vehicle and ac-
cess the Actuators screen. The following is a list of
the engine control system functions accessible
through Actuators screens. Stop All Tests
Ignition Coil #1
Fuel Injector #1
Fuel Injector #2
Fuel Injector #3
14 - 134 FUEL SYSTEMS Ä

(18) Remove fuel rail mounting bolts. Lift fuel rail
assembly off of intake manifold.
INSTALLATION
(1) Be sure injectors are seated into the receiver
cup with lock ring in place. (2) Make sure the injector holes are clean and all
plugs have been removed. (3) To ease installation, lubricate injector O-ring
with a drop of clean engine oil. (4) Put the tip of each injector into their ports.
Push the assembly into place until the injectors are
seated in the ports. (5) Install fuel rail attaching bolts. Tighten bolts
to 13 N Im (115 in. lbs.) torque.
(6) Install fuel supply and return tube holddown
bolt and the vacuum crossover tube holddown bolt.
Tighten bolts to 10 N Im (95 in. lbs.) torque.
(7) Connect fuel injector wiring harness to engine
wiring harness. (8) Connect vacuum harness to fuel rail assembly.
(9) Remove covering from lower intake manifold
and clean surface. (10) Place intake manifold gaskets with beaded
sealer up on lower manifold. Put air intake in place.
Install ignition coil. Install attaching fasteners and
tighten to 13 N Im (115 in. lbs.) torque.
(11) Connect fuel lines to fuel rail. Tighten hose
clamps to 1 N Im (10 in. lbs.) torque.
(12) Connect vacuum harness to air intake plenum
and fuel pressure regulator. (13) Connect coolant temperature sensor electrical
connector to sensor. (14) Connect EGR tube flange to intake plenum.
Tighten mounting nuts to 22 N Im (200 in. lbs.)
torque. (15) Connect PCV and brake booster supply hose
to intake plenum. (16) Connect idle air control motor and throttle po-
sition sensor (TPS) electrical connectors. (17) Connect vacuum vapor harness to throttle
body. (18) Install throttle cable.
(19) Install air inlet hose assembly.
(20) Connect negative cable to battery.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for either 7 minutes, until the test is stopped, or un-
til the ignition switch is turned to the Off position. (21) With the ignition key in ON position, access
the DRBII scan tool ASD Fuel System Test to pres-
surize the fuel system. Check for leaks.
FUEL PRESSURE REGULATOR SERVICE
REMOVAL
WARNING: THE 3.0L MPI FUEL SYSTEM IS UNDER
A CONSTANT PRESSURE OF APPROXIMATELY 330
KPA (48 PSI). PERFORM FUEL PRESSURE RE-
LEASE PROCEDURE BEFORE SERVICING THE
FUEL PRESSURE REGULATOR.
(1) Perform the Fuel Pressure Release Procedure.
(2) Disconnect negative cable from battery.
Fig. 10 Removing Air Intake Plenum
Fig. 11 Vacuum Connections at the Fuel Rail
Fig. 12 Fuel Injector Wiring Harness
Ä FUEL SYSTEMS 14 - 141

² transaxle gear selection (park/neutral switch)
The PCM also adjusts engine idle speed through
the idle air control motor based on the following in-
puts.
² brake switch
² engine coolant temperature
² engine speed (crankshaft position sensor)
² throttle position
² transaxle gear selection (park/neutral switch)
² vehicle speed
The auto shutdown (ASD) and fuel pump relays are
mounted externally, but turned on and off by the
PCM through the same circuit. The camshaft position sensor and crankshaft posi-
tion sensor signals are sent to the PCM. If the PCM
does not receive both signals within approximately
one second of engine cranking, it deactivates the
ASD and fuel pump relays. When these relays are
deactivated, power is shut off to the fuel injector, ig-
nition coil, oxygen sensor heating element and fuel
pump. The PCM contains a voltage converter that
changes battery voltage to a regulated 8.0 volts. The
8.0 volts power the camshaft position sensor, crank-
shaft position sensor and vehicle speed sensor. The
PCM also provides a 5.0 volts supply for the coolant
temperature sensor, manifold absolute pressure sen-
sor and throttle position sensor.
AIR CONDITIONING SWITCH SENSEÐPCM INPUT
When the air conditioning or defrost switch is put
in the ON position and the low pressure, high pres-
sure and ambient temperature switches are closed,
the PCM receives an input for air conditioning. After
receiving this input, the PCM activates the A/C com-
pressor clutch by grounding the A/C clutch relay.
BATTERY VOLTAGEÐPCM INPUT
The PCM monitors the battery voltage input to de-
termine fuel injector pulse width and generator field
control. If battery voltage is low the PCM will in-
crease injector pulse width.
BRAKE SWITCHÐPCM INPUT
When the brake switch is activated, the PCM re-
ceives an input indicating that the brakes are being
applied. the brake signal cancels speed control and
unlocks the torque convertor. The brake switch is
mounted on the brake pedal support bracket.
CAMSHAFT POSITION SENSORÐPCM INPUT
The camshaft position sensor provides cylinder
identification to the powertrain control module
(PCM) (Fig. 3). The sensor generates pulses as
groups of notches on the camshaft sprocket pass un-
derneath it (Fig. 4). The PCM keeps track of crank-
shaft rotation and identifies each cylinder by the pulses generated by the notches on the camshaft
sprocket. Four crankshaft pulses follow each group of
camshaft pulses.
When the PCM receives two camshaft pulses fol-
lowed by the long flat spot on the camshaft sprocket,
it knows that the crankshaft timing marks for cylin-
der one are next (on driveplate). When the PCM re-
ceives one camshaft pulse after the long flat spot on
the sprocket, cylinder number two crankshaft timing
marks are next. After 3 camshaft pulses, the PCM
knows cylinder four crankshaft timing marks follow.
One camshaft pulse after the three pulses indicates
cylinder five. The two camshaft pulses after cylinder
5 signals cylinder six (Fig. 4). The PCM can synchro-
nize on cylinders 1 or 4.
When metal aligns with the sensor, voltage goes
low (less than 0.5 volts). When a notch aligns with
the sensor, voltage spikes high (5.0 volts). As a group
of notches pass under the sensor, the voltage
switches from low (metal) to high (notch) then back
Fig. 3 Camshaft Position Sensor
Fig. 4 Camshaft Sprocket
Ä FUEL SYSTEMS 14 - 147

WIDE OPEN THROTTLE MODE This is an OPEN LOOP mode. During wide-open-
throttle operation, the following inputs are received
by the PCM:
² battery voltage
² engine coolant temperature
² manifold absolute pressure
² engine speed
² throttle position
When the PCM senses wide open throttle condition
through the throttle position sensor (TPS) it will:
² De-energize the air conditioning relay. This dis-
ables the air conditioning system.
² Provide a ground for the electrical EGR transducer
(EET) solenoid. When the PCM grounds the solenoid,
the EGR system stops operating. The exhaust gas oxygen content input is not ac-
cepted by the PCM during wide open throttle opera-
tion. The PCM will adjust injector pulse width to
supply a predetermined amount of additional fuel.
IGNITION SWITCH OFF MODE When the ignition switch is turned to the OFF po-
sition, the following occurs:
² All outputs are turned off.
² No inputs are monitored.
² The PCM shuts down.
THROTTLE BODY
The throttle body assembly is located on the left
side of the intake manifold plenum (Fig. 19). The
throttle body houses the throttle position sensor and
the idle air control motor. Air flow through the throt- tle body is controlled by a cable operated throttle
blade located in the base of the throttle body.
FUEL SUPPLY CIRCUIT
Fuel is pumped to the fuel rail by an electrical
pump in the fuel tank. The pump inlet is fitted with
a strainer to prevent water and other contaminants
from entering the fuel supply circuit. Fuel pressure is controlled to a preset level above
intake manifold pressure by a pressure regulator.
The regulator is mounted on the fuel rail. The regu-
lator uses intake manifold pressure as a reference.
FUEL INJECTORS AND FUEL RAIL ASSEMBLY
Six fuel injectors are retained in the fuel rail by
lock rings (Fig. 20). The rail and injector assembly is
installed in position with the injectors inserted in re-
cessed holes in the intake manifold.
Fig. 19 Throttle Body
Fig. 20 Fuel Rail Assembly
Ä FUEL SYSTEMS 14 - 155

FUEL PRESSURE REGULATOR
The pressure regulator is a mechanical device lo-
cated on the fuel rail, downstream of the fuel injec-
tors (Fig. 21). The regulator maintains a constant
330 kPa (48 psi) across the fuel injector tip. The regulator contains a spring loaded rubber dia-
phragm that covers the fuel return port. When the
fuel pump is operating, fuel flows past the injectors
into the regulator, and is restricted from flowing any
further by the blocked return port. When fuel pres-
sure reaches 330 kPa (48 psi) it pushes on the dia-
phragm, compresses the spring, and uncovers the
fuel return port. The diaphragm and spring con-
stantly move from an open to closed position keeping
fuel pressure consistent.
Fig. 21 Fuel Pressure Regulator
14 - 156 FUEL SYSTEMS Ä

(25) Check the heated oxygen sensor electrical con-
nector for damage (Fig. 14). (26) Inspect the generator wiring connections for
damage. (27) Check the accessory drive belt tension.
(28) Check the 60-way electrical connection at the
PCM (Fig. 15) for damage or spread terminals. Ver-
ify that the 60-way connector is fully inserted into
the PCM socket. Ensure the wires are not stretched
or pulled out of the connector.
(29) Check for full insertion of the relays in the
power distribution center (Fig. 16).
(30) Check battery cable connections.
(31) Check the power brake booster hose connec-
tion (without Anti-lock Brake Systems) (Fig. 17). (32) Check the speed control vacuum connection
(Fig. 18). (33) Inspect hose and wiring connections at fuel
pump. Check that wiring connector is making con-
tact with terminals on pump.
Fig. 12 PCV System
Fig. 13 Crankshaft Position Sensor and Vehicle Speed Sensor
Fig. 14 MAP Sensor and Heated Oxygen Sensor
Fig. 15 Powertrain Control Module (PCM)
Fig. 16 Power Distribution Center
14 - 160 FUEL SYSTEMS Ä

line. However, these could result in a rich or lean
condition causing an oxygen sensor fault to be stored in
the PCM. Secondary Ignition Circuit - The PCM cannot
detect an inoperative ignition coil, fouled or worn spark
plugs, ignition cross firing, or open spark plug cables. Engine Timing - The PCM cannot detect an incor-
rectly indexed timing chain, camshaft sprocket and
crankshaft sprocket. However, these could result in a
rich or lean condition causing an oxygen sensor fault to
be stored in the PCM. Cylinder Compression - The PCM cannot detect
uneven, low, or high engine cylinder compression. Exhaust System - The PCM cannot detect a
plugged, restricted or leaking exhaust system. Fuel Injector Malfunctions - The PCM cannot
determine if a fuel injector is clogged, the needle is
sticking or the wrong injector is installed. However,
these could result in a rich or lean condition causing an
oxygen sensor fault to be stored in the PCM. Excessive Oil Consumption - Although the PCM
monitors exhaust stream oxygen content when the
system is in closed loop, it cannot determine excessive
oil consumption. Throttle Body Air Flow - The PCM cannot detect a
clogged or restricted air cleaner inlet or filter element. Evaporative System - The PCM will not detect a
restricted, plugged or loaded evaporative purge canis-
ter. Vacuum Assist - Leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices are not monitored by the PCM. How-
ever, these could result in a MAP sensor fault being
stored in the PCM. PCM System Ground - The PCM cannot determine
a poor system ground. However, a diagnostic trouble
code may be generated as a result of this condition. PCM Connector Engagement - The PCM cannot
determine spread or damaged connector pins. How-
ever, a diagnostic trouble code may be generated as a
result of this condition.
HIGH AND LOW LIMITS
The powertrain control module (PCM) compares in-
put signal voltages from each input device with estab-
lished high and low limits for the device. If the input
voltage is not within limits and other diagnostic
trouble code criteria are met, a diagnostic trouble code
will be stored in memory. Other diagnostic trouble code
criteria might include engine RPM limits or input
voltages from other sensors or switches that must be
present before a fault condition can be verified.
DIAGNOSTIC TROUBLE CODE DESCRIPTION
A diagnostic trouble code indicates that the power-
train control module (PCM) has recognized an abnor- mal condition in the system. Diagnostic trouble codes
can be obtained from the malfunction indicator lamp
(Check Engine lamp on the instrument panel) or from
the DRBII scan tool. Diagnostic trouble codes indicate
the results of a failure but do not identify the failed
component directly.
SYSTEM TESTS
WARNING: APPLY PARKING BRAKE AND/OR BLOCK
WHEELS BEFORE PERFORMING ANY TEST ON AN
OPERATING ENGINE.
OBTAINING DIAGNOSTIC TROUBLE CODES
(1) Connect the DRBII scan tool to the data link
connector located in the engine compartment near the
driver side strut tower (Fig. 1). (2) Start the engine if possible, cycle the transaxle
selector and the A/Cswitch if applicable. Shut off the
engine. (3) Turn the ignition switch on, access Read Fault
Screen. Record all the fault messages shown on the
DRBII scan tool. Observe the malfunction indicator
lamp (check engine lamp on the instrument panel). The
lamp should light for 2 seconds then go out (bulb
check). Diagnostic trouble code erasure; access erase
diagnostic trouble code data
STATE DISPLAY TEST MODE
The switch inputs used by the powertrain control
module (PCM) have only two recognized states, HIGH
and LOW. For this reason, the PCM cannot recognize
the difference between a selected switch position ver-
sus an open circuit, a short circuit, or a defective
switch. If the change is displayed, it can be assumed
that the entire switch circuit to the PCM is functional.
From the state display screen access either State
Display Inputs and Outputs or State Display Sensors.
STATE DISPLAY INPUTS AND OUTPUTS
Connect the DRBII scan tool to the vehicle and access
the State Display screen. Then access Inputs and
Outputs. The following is a list of the engine control
system functions accessible through the Inputs and
Outputs screen. Park/Neutral Switch
Speed Control Resume
Brake Switch
Speed Control On/Off
Speed Control Set
A/C Switch Sense
S/C Vent Solenoid
Ä FUEL SYSTEMS 14 - 163

STEERING
CONTENTS
page page
ACUSTAR STANDARD AND TILT STEERING COLUMN ............................ 28
AUTOMATIC TRANSMISSION SHIFTER/IGNITION INTERLOCK .......................... 36
GENERAL INFORMATION .................. 1 POWER STEERING GEAR
................ 25
POWER STEERING PUMPS ................ 1
SPECIFICATIONS AND TIGHTENING REFERENCE .......................... 42
GENERAL INFORMATION
Safety goggles should be worn at all times
when working on any steering gear or pump. Throughout this group, references may be made to
a particular vehicle by letter or number designation.
A chart showing the breakdown of these designations
is included in the Introduction Section at the front of
this service manual. The power steering system consists of these four
major components. Power Steering Pump, Power
Steering Gear, Pressure Hose, and Return Line.
Turning of the steering wheel is converted into lin-
ear travel through the meshing of the helical pinion teeth with the rack teeth. Power assist steering is
provided by an open center, rotary type control valve.
It is used to direct oil from the power steering pump
to either side of the integral steering rack piston. Road feel is controlled by the diameter of a torsion
bar which initially steers the vehicle. As steering ef-
fort increases as in a turn, the torsion bar twists,
causing relative rotary motion between the rotary
valve body and valve spool. This movement directs
oil behind the integral rack piston, which in turn,
builds up hydraulic pressure and assists in the turn-
ing effort.
POWER STEERING PUMPS
INDEX
page page
Checking Power Steering Fluid Level .......... 9
Flow Control Valve Fitting O-Ring Seal ........ 23
General Information ........................ 1
Power Steering Hoses ..................... 11
Power Steering Pressure Switch ............. 10
Power Steering Pump Fluid Reservoirs ........ 22 Power Steering Pump Pressure Test
........... 9
Power Steering Pump Pulley Service .......... 20
Power Steering Pump Removal .............. 12
Power Steering Pump Service ................ 2
Power Steering PumpÐInitial Operation ....... 24
Steering Components Service Diagnosis ........ 2
GENERAL INFORMATION
Hydraulic pressure for operation of the power
steering gear is provided by a belt driven power
steering pump. The power steering pump is a con-
stant flow rate and displacement, vane type pump.
Different styles of Saginaw power steering pumps are
used depending on the engine application of the ve-
hicle. On all four cylinder and 3.0-liter V-6 applications
the Saginaw Ham Can power steering pump is used
(Fig. 1). On the 3.3 & 3.8-liter V-6 and Turbo III applica-
tions, different versions of the Saginaw T/C style
power steering pump is used (Fig. 2). The 3.3 & 3.8 liter V-6 engine application uses the T/C style power
steering pump with a remote mounted reservoir for
the power steering fluid. On the Turbo III application
of the T/C style power steering pump, the power
steering fluid reservoir is integral to the power steer-
ing pump. On the integral reservoir type pump (Fig. 1) the
pump housing and internal components are combined
with the reservoir to form a one-piece mechanism. The Saginaw T/C style power steering pump (Fig.
2), consists of the power steering pump internal com-
ponents and pump housing. The Saginaw T/C style
power steering pump though has no internal reser-
voir for the power steering fluid. Depending on vehi-
Ä STEERING 19 - 1