1993 CHEVROLET DYNASTY service

CAUTION: Avoid application of rust prevention
compounds or undercoating materials to exhaust
system floor pan heat shields on cars if equipped.
Light overspray near the edges is permitted. Appli-
cation of coating will greatly reduce the efficiency
of the heat shields resulting in excessive floor pan
temperatures and objectionable fumes.
The combustion reaction caused by the catalyst re-
leases additional heat in the exhaust system. Caus-
ing temperature increases in the area of the reactor
under severe operating conditions. Such conditions
can exist when the engine misfires or otherwise does
not operate at peak efficiency. Do notremove spark
plug wires from plugs or by any other means short
out cylinders if exhaust system is equipped with cat-
alytic converter. Failure of the catalytic converter
can occur due to temperature increases caused by un-
burned fuel passing through the converter. The use of the catalysts also involves some non-au-
tomotive problems. Unleaded gasoline must be used
to avoid poisoning the catalyst core. Do not allow en- gine to operate above 1200 RPM in neutral for ex-
tended periods over 5 minutes. This condition may
result in excessive exhaust system/floor pan temper-
atures because of no air movement under the vehicle.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
To assist in the control of oxides of nitrogen (NOx)
in engine exhaust, some engines are equipped with
an exhaust gas recirculation system. The use of ex-
haust gas to dilute incoming air/fuel mixtures lowers
peak flame temperatures during combustion, thus
limiting the formation of NOx. Exhaust gases are taken from openings in the ex-
haust gas crossover passage in the intake manifold.
REFER TO SECTION 25 EMISSION SYSTEMS
FOR A COMPLETE DESCRIPTION, DIAGNOSIS
AND SERVICE PROCEDURES ON THE EXHAUST
GAS RECIRCULATION SYSTEM AND COMPO-
NENTS.
EXHAUST SYSTEM DIAGNOSIS
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 3

SERVICE PROCEDURES INDEX
page page
Exhaust Pipes, Mufflers and Tailpipes .......... 4
Intake and Exhaust Manifolds ServiceÐTBI Engine.6Intake and Exhaust ManifoldsÐFlexible Fuel Engine.7
Intake and Exhaust ManifoldsÐTBI Engine ...... 5
Intake/Exhaust Manifold ServiceÐ3.0L Engine . . . 13
Intake/Exhaust Manifold ServiceÐ3.3/3.8L Engines.19
Intake/Exhaust Manifolds and Turbocharger ServiceÐTurbo III Engine .................. 9
Intake/Exhaust Manifolds ServiceÐFlexible Fuel Engines ............................... 7
EXHAUST PIPES, MUFFLERS AND TAILPIPES
REMOVAL
(1) Raise vehicle on hoist and apply penetrating oil
to clamp bolts and nuts of component being removed. (2) Tail pipes are integral with the muffler (Fig. 5).
Remove clamp at slip joint. Separate at slip joint. (3) Remove clamps and supports (Figs. 6, 7, 8, and 9)
from exhaust system to permit alignment of parts
during assembly. (4) When removing tailpipe, raise rear of vehicle to
relieve body weight from rear springs to provide clear-
ance between pipe and rear axle parts. (5) Clean ends of pipes and/or muffler to assure
mating of all parts. Discard broken or worn insulators,
rusted clamps, supports and attaching parts. When replacement is required on any compo-
nent of the exhaust system, it is most important
that original equipment parts (or their equiva-
lent) be used;
² To insure proper alignment with other parts in the
system.
² Provide acceptable exhaust noise levels and does not
change exhaust system back pressure that could affect
emissions and performance.
INSTALLATION
(1) Assemble ball joint connection pipes, supports
and clamps loosely to permit alignment of all parts.
Fig. 6 Insulator Tail Pipe and Muffler Support
Fig. 7 Underfloor Converter or Extension Pipe SupportÐ2 Places
Fig. 5 Tail Pipe with MufflerÐTypical
11 - 4 EXHAUST SYSTEM AND INTAKE MANIFOLD Ä

for diagnostic and service procedures on the air control
valve and temperature sensor located in the air
cleaner.
INTAKE AND EXHAUST MANIFOLDS SERVICEÐTBI
ENGINE
Intake and exhaust manifolds use a one piece gasket.
Service procedures requiring removal and installation
( of either ) must include both manifolds.
FUEL SYSTEM PRESSURE RELEASE PROCE- DURE
The Fuel System is under a constant pressure
of at least 265 kPa (39 psi). Before servicing the
fuel pump, fuel lines, fuel filter, throttle body or
fuel injector, the fuel system pressure must be
released. (a) Loosen fuel filler cap to release fuel tank pres-
sure. (b) Disconnect injector wiring harness from engine
harness. (c) Connect a jumper wire to ground terminal
Number 1 of the injector harness (Fig. 2) to engine
ground. (d) Connect a jumper wire to the positive terminal
Number 2 of the injector harness (Fig. 2) and touch
the battery positive post for no longer than 5 seconds.
This releases system pressure. (e) Remove jumper wires.
(f) Continue fuel system service.
REMOVAL
(1) Perform fuel system pressure release procedure
before attempting any repairs. (2) Disconnect negative battery cable. Drain cool-
ing system. Refer to Cooling System, Group 7 for pro-
cedure. (3) Remove air cleaner and disconnect all vacuum
lines, electrical wiring and fuel lines from throttle
body. (4) Remove throttle linkage.
(5) Loosen power steering pump and remove belt.
(6) Remove power brake vacuum hose from intake
manifold. (7) Disconnect EGR tube from intake manifold and
remove water hoses from water crossover. (8) Raise vehicle and remove exhaust pipe from
manifold. (9) Remove power steering pump assembly and set
aside. (10) Remove intake manifold retaining screws
(Fig. 3). (11) Lower vehicle and remove intake manifold.
(12) Remove exhaust manifold retaining nuts (Fig.
3). (13) Remove exhaust manifold.
Fig. 2 Injector Harness Connector
Fig. 3 Intake and Exhaust Manifold Attaching PointsÐ2.2/2.5L Engines
Fig. 1 Air HeaterÐTBI Engine
11 - 6 EXHAUST SYSTEM AND INTAKE MANIFOLD Ä

CLEANING AND INSPECTION
(1) Discard gaskets and clean all gasket surfaces
on both manifolds and on cylinder head. (2) Test gasket surfaces of manifolds for flatness
with a straight edge. Surfaces must be flat within
0.15mm per 300mm (.006 in. per foot) of manifold
length. (3) Inspect manifolds for cracks and distortion.
INSTALLATION
(1) Install a new intake and exhaust manifold gas-
ket. Coat steel gasket lightly with Gasket Sealer on
manifold side. Do notcoat composition gasket with
(any) sealer. (2) Set exhaust manifold in place. Tighten retain-
ing nuts starting at center and progressing outward
in both directions to 23 N Im (200 in. lbs.) torque. Re-
peat this procedure until all nuts are at specified
torque. (3) Set intake manifold in place.
(4) Raise vehicle and tighten retaining screws
starting at center and progressing outward in both
directions to 23 N Im (200 in. lbs.) torque (Fig. 3). Re-
peat this procedure until all screws are at specified
torque. (5) Reverse removal procedures 1-9 for installation.
(6) With the DRBII Scan Tool use ASD Fuel Sys-
tem Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
INTAKE AND EXHAUST MANIFOLDSÐFLEXIBLE
FUEL ENGINE
INTAKE MANIFOLD
The manifold is die-cast aluminum with upper ple-
num and 4 tubes lower runners. These attach to the
cylinder head, with each runner leading directly to a
cylinder. The manifold is also machined for fuel rail attach-
ment and injector installation. The throttle body is
installed on the upper plenum of the manifold.
EXHAUST MANIFOLD
All high strength iron casting that intermesh with
the intake manifold. For standard engines a four
branch design collects and directs exhaust gases to
the conical (articulated joint connection) outlet.
INTAKE/EXHAUST MANIFOLDS
SERVICEÐFLEXIBLE FUEL ENGINES
Intake and exhaust manifolds use a one piece gas-
ket. Service procedures requiring removal and instal-
lation of either must include both manifolds.
SERVICE PRECAUTIONS
Methanol is more toxic than gasoline. Always re-
lease fuel system pressure before servicing fuel sys-
tem components and wear methanol resistant gloves
and eye protection. Avoid breathing methanol vapors or ingesting
methanol. Headaches, dizziness and even uncon-
sciousness could result from breathing these vapors.
Serious injury, blindness and even death could result
from ingesting methanol. Methanol vapors are extremely flammable and can
travel along the ground. Service vehicles in well ven-
tilated areas and avoid ignition sources. Never
smoke while servicing the vehicle. Do not allow methanol to contact skin. Prolonged
contact with methanol can cause dry skin or an al-
lergic skin reaction. Also, prolonged contact could re-
sult in absorption through the skin.
FUEL SYSTEM PRESSURE RELEASE PROCEDURE
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
WEAR METHANOL RESISTANT GLOVES AND EYE
PROTECTION WHILE SERVICING THE FUEL SYS-
TEM.
(a) Disconnect negative cable from battery.
(b) Remove fuel filler cap.
(c) Remove the protective cap from the fuel pres-
sure test port on the fuel rail (Fig. 4).
(d) Place the open end of fuel pressure release
hose, tool number C-4799-1, into an approved gas-
oline container. Connect the other end of hose
C-4799-1 to the fuel pressure test port (Fig. 5).
Fuel pressure will bleed off through the hose into
the gasoline container. Fuel gauge C-4799-A con-
tains hose C-4799-1.
Fig. 4 Fuel Pressure Test Port
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 7

EXHAUST MANIFOLD
REMOVAL (1) Disconnect exhaust pipe from manifold articu-
late joint. (2) Disconnect the heated oxygen sensor electrical
connection. (3) Remove 8 exhaust manifold retaining nuts and
remove exhaust manifold (Fig. 9).
CLEANING AND INSPECTION
(1) Discard gasket and clean all gasket surfaces of
manifolds and cylinder head. (2) Test gasket surfaces for flatness with straight
edge. Surface must be flat within 0.15 mm per 300
mm (.006 in. per foot) of manifold length. (3) Inspect manifolds for cracks or distortion.
EXHAUST MANIFOLD
INSTALLATION
(1) Install new two-sided grafoil or equivalent in-
take/exhaust manifold gasket. DO NOT APPLY
SEALER. (2) Set exhaust manifold in place. Install and
tighten retaining nuts, starting at center and pro-
gressing outward in both directions to 23 N Im (200
in. lbs.) torque. Repeat this procedure until all nuts
are at specified torque.
INTAKE MANIFOLD
INSTALLATION
(1) Position intake manifold, install, and tighten 8
retaining screws starting at center and progressing
outward in both directions to 23 N Im (200 in. lbs.)
torque. Repeat this procedure until all screws are at
specified torque (Fig. 9). (2) Install PCV vacuum harness and vacuum vapor
harness (Fig. 8). (3) Connect vacuum hose from fuel pressure regu-
lator. (4) Connect fuel injector wiring connector (Fig. 8).
(5) Close fuel tube clip around fuel tubes and in-
stall fastener. (6) Lubricate the ends of the chassis fuel tubes
with 30 wt oil. Connect fuel supply and return hoses
to chassis fuel tube assembly. pull back on the quick
connect fitting to ensure complete insertion. (Refer to
Fuel Hoses, Clamps and Quick Connect Fittings in
Group 14 Fuel Systems). (7) Connect automatic idle speed (AIS) motor and
throttle position sensor (TPS) wiring connectors (Fig.
7). (8) Connect accelerator and speed control cables.
Install brake booster vacuum supply hoses. (9) Reconnect negative battery cable.
(10) Install air cleaner hose to throttle body assem-
bly (Fig. 6). (11) With the DRBII Scan Tool use ASD Fuel Sys-
tem Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
INTAKE/EXHAUST MANIFOLDS AND
TURBOCHARGER SERVICEÐTURBO III ENGINE
INTAKE MANIFOLD
REMOVAL
(1) Perform fuel system pressure release procedure
before attempting any repairs. (2) Disconnect negative battery cable. Drain cool-
ing system. Refer to Cooling System, Group 7. (3) Remove fresh air duct from air filter housing.
Remove inlet hose from the intercooler (Fig. 1). (4) Remove radiator hose to cylinder head (Fig. 2).
(5) Remove DIS Ignition Coils from intake mani-
fold (Fig. 3). (6) Remove accelerator and speed control cables
(Fig. 4).
Fig. 9 Intake and Exhaust Manifolds Attaching Points
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 9

(13) Disconnect articulated exhaust pipe joint from
turbocharger housing. (14) Remove turbocharger coolant inlet line assem-
bly from engine (Fig. 11). (15) Lift turbocharger off manifold mounting studs
and lower assembly down and out of vehicle.
EXHAUST MANIFOLD
REMOVAL
Remove 9 exhaust manifold retaining fasteners and
remove exhaust manifold (Fig. 14).
CLEANING AND INSPECTION
(1) Discard gasket and clean all gasket surfaces of
manifolds and cylinder head. (2) Test manifold gasket surfaces for flatness with
straight edge. Surface must be flat within 0.15 mm
per 300 mm (.006 in. per foot) of manifold length. (3) Inspect manifolds for cracks or distortion. Re-
place manifold if necessary.
EXHAUST MANIFOLD
INSTALLATION
(1) Install new manifold gasket. DO NOT APPLY
SEALER . (2) Set exhaust manifold in place. Tighten retain-
ing nuts and bolt, starting at center and progressing
outward in both directions to 23 N Im (200 in. lbs.)
torque. Repeat this procedure until all fasteners are
at specified torque (Fig. 14).
TURBOCHARGER
INSTALLATION
(1) Position turbocharger on exhaust manifold. Ap-
ply antiseize compound to threads and install the
lower (passenger side) retaining nut (Fig. 12).
Tighten nut to 54 N Im (40 ft. lbs.) torque.
(2) Apply thread sealant to lower (inlet) coolant
line fitting and install fitting into turbocharger hous-
ing (Fig. 11). (3) Install lower coolant line assembly to engine
(Fig. 11). (4) Install oil drain back tube and fitting (with
new gasket) to turbocharger housing (Fig. 13). (5) Install turbocharger to block support bracket
and install screws finger tight (Fig. 13). Tighten
block screw FIRST to 54 N Im (40 ft. lbs.) torque,
then tighten screw to turbocharger housing to 27
N Im (20 ft. lbs.) torque.
(6) Reposition exhaust pipe. Tighten articulated
joint shoulder bolts to 28 N Im (250 in. lbs.) torque.
(7) See Suspension, Group 2, and install right
driveshaft and wheel and tire assembly. Install air
deflector on crossmember. (8) From Above: Install three turbocharger to
manifold retaining nuts. Tighten to 54 N Im (40 ft.
lbs.) torque (Fig. 12). (9) Reconnect Heated Oxygen sensor electrical con-
nection and vacuum lines. (10) Attach oil feed line to turbocharger bearing
housing. Tighten fitting to 14 N Im (125 in. lbs.)
torque (Fig. 12). (11) Install coolant line and tighten fittings to 41
N Im (30 ft. lbs.) torque (Fig. 11).
(12) Install air cleaner support (Fig. 1).
(13) Align front engine mount in crossmember
bracket. Install through bolt and tighten to 54 N Im
(40 ft. lbs.) torque. (14) Install air cleaner assembly (Fig. 1).
(15) Fill cooling system. Refer to Cooling System,
Group 7 for procedure.
INTAKE/EXHAUST MANIFOLD SERVICEÐ3.0L
ENGINE
The intake system has a large air intake plenum of
aluminum alloy and a cross type intake manifold
(Fig. 2).
Fig. 13 Oil Return Tube and Support Bracket
Fig. 14 Exhaust ManifoldÐTurbo III Engine
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 13

(e) Remove jumper wires.
(f) Continue fuel system service.
(4) Remove throttle cable and transaxle kickdown
linkage (Fig. 4). (5) Remove automatic idle speed (AIS) motor and
throttle position sensor (TPS) wiring connectors from
throttle body (Fig. 5). (6) Remove vacuum hose harness from throttle body
(Fig. 5). (7) Remove PCV and Brake booster hoses from Air
Intake Plenum. (8) Remove ignition coil from intake plenum (Fig. 6).
(9) Remove wiring connectors from coolant tempera-
ture sensor (Fig. 7). (10) Remove vacuum connections from air intake
plenum vacuum connector. (11) Remove fuel hoses from fuel rail (Fig. 7).
WARNING: WRAP SHOP TOWELS AROUND HOSES
TO CATCH ANY GASOLINE SPILLAGE. (12) Remove (8) Fasteners from Air Intake Plenum
to Intake Manifold (Fig. 8). (13) Remove air intake plenum (Fig. 9).
(14) Cover intake manifold with suitable cover when
servicing. (15) Remove vacuum hoses from fuel rail and fuel
pressure regulator (Fig. 10). (16) Disconnect Fuel Injector wiring harness from
engine wiring harness (Fig. 11). (17) Remove fuel pressure regulator attaching bolts
and remove regulator from rail (Fig. 12). Be careful
not to damage the rubber injector O-rings upon
removal from the ports. (18) Remove fuel rail attaching bolts and lift fuel rail
assembly from intake manifold. (19) Separate radiator hose from thermostat hous-
ing and heater hose from heater pipe. (20) Remove (8) nut and washer assemblies and
remove intake manifold (Fig. 2).
INSPECTION
Check for:
² Damage and cracks of each section (Fig. 13).
² Clogged water passages in end cross overs.
² Check for distortion of the cylinder head mounting
surface using a straightedge and thickness gauge (Fig.
14). Refer to (Fig. 15) for Specifications.
INSTALLATION
(1) Position new intake manifold gaskets on cylinder
head and install intake (cross) manifold. (2) Install (8) nuts and washers and tighten in
several steps in order shown in (Fig. 16) to 20 N Im
(174 in. lbs.). (3) Make sure the injector holes are clean and all
plugs have been removed. (4) Lube injector O-ring with a drop of clean en-
gine oil to ease installation. (5) Put the tip of each injector into their ports.
Push the assembly into place until the injectors are
seated in the ports. (6) Install the (3) fuel rail attaching bolts and
torque to 13 N Im (115 in. lbs.).
(7) Install fuel pressure regulator onto fuel rail. In-
stall attaching bolts to intake manifold. Torque reg-
ulator nuts and bracket bolts to 10 N Im (95 in. lbs.)
(Fig. 12). (8) Install fuel supply and return tube hold-down
bolt and the vacuum crossover tube hold-down bolt
and torque to 10 N Im (95 in. lbs.).
(9) Connect fuel injector wiring harness to engine
wiring harness (Fig. 11). (10) Connect vacuum harness to fuel pressure reg-
ulator and fuel rail assembly (Fig. 10). (11) Remove covering from lower intake manifold
and clean surface. (12) Place intake manifold gaskets with beaded
sealant side up on lower manifold. Put air intake in
Fig. 3 Throttle Body Assembly 3.0L
Fig. 4 Throttle Cable Attachment
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 15

(2) Attach exhaust pipe to exhaust manifold and
tighten shoulder bolt to 28 N Im (250 in. lbs.)
(3) Attach crossover pipe to exhaust manifold and
tighten bolt to 69 N Im (51 ft. lbs.)
(4) Connect heated oxygen sensor lead (Fig. 18).
(5) Install front exhaust manifold and attach ex-
haust crossover. (6) Install front manifold heat shield and tighten
attaching screws to 15 N Im (130 in. lbs.) (Fig. 2).
INTAKE/EXHAUST MANIFOLD SERVICEÐ3.3/3.8L
ENGINES
INTAKE MANIFOLD
REMOVAL
(1) Perform fuel system pressure release procedure,
Before attempting any repairs. (2) Disconnect negative battery cable. Drain cool-
ing system. Refer to Cooling System, Group 7.
FUEL SYSTEM PRESSURE RELEASE PROCE- DURE
The MPI fuel system is under a constant pressure
of about 330 kPa (48 psi). Before servicing the fuel
pump, fuel lines, fuel filter, throttle body or fuel
injector, the fuel system pressure must be released.
(a) Loosen fuel filler cap to release fuel tank pres-
sure. (b) Disconnect injector wiring harness from engine
harness.
(c) Connect a jumper wire to ground terminal Num-
ber 1 of the injector harness (Fig. 1) to engine ground.
(d) Connect a jumper wire to the positive terminal
Number 2 of the injector harness (Fig. 1) and touch
the battery positive post for no longer than 5 seconds.
This releases system pressure. (e) Remove jumper wires.
(f) Continue fuel system service.
(3) Remove air cleaner to throttle body hose assem-
bly (Fig. 2).
Fig. 20 Check Exhaust Manifold Mounting Surface
Fig. 21 Identify Exhaust Manifold Gaskets
Fig. 1 Injector Harness Connectors
Fig. 2 Throttle Body AssemblyÐ3.3/3.8L Engines
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 19