Removal Procedure
Important: The intake manifold, throttle body, fuel rail, and injectors may be
removed as an assembly. If not servicing the individual components, remove
the manifold as a complete assembly.
- Loosen the clamps at the
throttle body and air cleaner.
- Remove the air cleaner outlet duct.
- Loosen the intake manifold
sight shield bolt (3).
- Remove the sight shield from the bracket (1).
- Remove the sight shield bracket (1) and nuts.
- Relieve the fuel system pressure. Refer to
Fuel Pressure Relief
in Engine Controls - 8.1 L.
- Disconnect the fuel feed and return pipes. Refer to
Metal Collar Quick Connect Fitting Service
in Engine Controls - 8.1 L.
- Disconnect the engine
harness clips from the studs on the front of dash.
- Disconnect the engine harness clip from the wheelhouse splash
shield.
- Disconnect the following electrical connectors:
• | Pressure cycling switch (1) |
• | Mass air flow (MAF) sensor (3) |
- Reposition engine harness branch to top of engine.
- Remove the connector position
assurance (CPA) retainer at the ignition coil harness.
- Disconnect the following electrical connectors:
• | Manifold absolute pressure (MAP) sensor (1) |
• | Ignition coil harness (2) |
• | Engine coolant temperature (ECT) sensor (3) |
- Remove the engine harness
bolt and studs
- Remove the CPA retainer at the ignition coil harness.
- Disconnect the following electrical connectors:
• | Ignition coil harness (3) |
• | Throttle position (TP) sensor (4) |
• | Electronic throttle control (ETC) (5) |
• | Purge valve solenoid (6) |
- Reposition the engine harness to the drivers side of the engine
compartment.
- Remove the bypass valve
vacuum hose (1) from the intake manifold.
- Disconnect the exhaust
gas recirculation (EGR) valve electrical connector (1).
- Remove the EGR pipe bolts
at the EGR adapter.
- Reposition the EGR pipe.
- Remove and discard the EGR valve pipe gasket.
- Remove the secondary air
injection (AIR) pipe nut from the fuel rail stud, if equipped.
- Remove the AIR pipe bolts at the exhaust manifold, if equipped.
- Disconnect the AIR pipe from the AIR pump pipe, if equipped.
- Remove and discard the AIR pipe gasket.
- Remove the AIR pipe nut
from the fuel rail stud, if equipped.
- Remove the AIR pipe bolts at the exhaust manifold, if equipped.
- Disconnect the AIR pipe from the AIR pump pipe, if equipped.
- Remove and discard the AIR pipe gasket.
- Reposition the AIR pump
hose clamp.
- Remove the AIR pump hose (1) from the pump pipe.
- Remove the AIR pump pipe
bolt from the cylinder head, if equipped.
- Remove the AIR pump pipe, if equipped.
- Remove the fuel pressure
regulator vacuum hose.
- If replacing the intake
manifold, remove the fuel rail studs.
- Remove the fuel rail.
- Remove the intake manifold
bolts.
Important: Do not attempt to loosen the manifold by prying under the gasket surface
with any tool.
- Remove the intake manifold.
Important: The intake manifold gaskets are not reusable.
- Remove and discard the intake manifold side gaskets.
- Remove and discard the
intake manifold end seals.
Important: The splash shield is secured using a snap-in fit. Do not distort the
splash shield. The splash shield is reusable.
- Remove the splash shield.
- If replacing the intake manifold, refer to
Intake Manifold Disassemble
in Engine Mechanical - 8.1 L
Unit Repair.
- Clean the intake manifold. Refer to
Intake Manifold Cleaning and Inspection
in Engine Mechanical -
8.1 L Unit Repair.
Installation Procedure
- If replacing the intake
manifold, refer to
Intake Manifold Assemble
in Engine Mechanical - 8.1 L Unit Repair.
- Install the splash shield.
- Ensure the splash shield
(2) snap fits between the cylinder heads (1).
- Install NEW intake manifold
end seals.
- Install NEW intake manifold
side gaskets onto the cylinder heads.
- Ensure the intake manifold
gasket tabs align with the hole in the head gasket.
- Ensure the intake manifold gasket tabs align with the slot in
the intake manifold end seals.
- Install the intake manifold
gaskets to the cylinder head with THIS SIDE UP stamped facing up.
- Install the intake manifold to the engine block.
- Apply bolt thread locking material GM P/N 12346004
or equivalent to the intake manifold bolts.
- Install the intake manifold.
- Apply thread adhesive GM P/N 12345382
or equivalent to a minimum of eight threads of the intake manifold bolts.
- Install the intake manifold bolts.
- Tighten the intake manifold bolts in sequence, using four passes
as shown.
Tighten
- Tighten the intake manifold bolts in sequence to 5 N·m
(44 lb in) on the first pass.
- Tighten the intake manifold bolts in sequence to 5 N·m
(44 lb in) on the second pass.
Inspect the intake manifold joints for signs of intake manifold shifting.
Correct as required.
- Tighten the intake manifold bolts in sequence to 10 N·m
(89 lb in) on the third pass.
- Tighten the intake manifold bolts in sequence to 12 N·m
(106 lb in) on the final pass.
Important: Lubricate the fuel injector O-ring seals with clean engine oil and install
onto the spray tip of each injector.
- If replacing the intake manifold, install the fuel rail.
- Install the fuel rail studs.
Tighten
Tighten the fuel rail studs to 12 N·m (106 lb in).
- Install the fuel pressure
regulator vacuum hose.
- Install the AIR pump pipe,
if equipped.
- Install the AIR pump pipe bolt to the cylinder head, if equipped.
Tighten
Tighten the AIR pump pipe bolt to 50 N·m (37 lb ft).
- Install the AIR pump hose
(1) to the pump pipe.
- Reposition the AIR pump hose clamp.
- Install a NEW AIR pipe
gasket.
- Connect the AIR pipe to the AIR pump pipe, if equipped.
- Install the AIR pipe bolts at the exhaust manifold, if equipped.
- Install the AIR pipe nut to the fuel rail stud, if equipped.
Tighten
• | Tighten the AIR pipe bolts to 25 N·m (18 lb ft). |
• | Tighten the AIR pipe nut to 12 N·m (106 lb in). |
- Install a NEW AIR pipe
gasket.
- Connect the AIR pipe to the AIR pump pipe, if equipped.
- Install the AIR pipe bolts at the exhaust manifold, if equipped.
- Install the (AIR) pipe nut to the fuel rail stud, if equipped.
Tighten
• | Tighten the AIR pipe bolts to 25 N·m (18 lb ft). |
• | Tighten the AIR pipe nut to 12 N·m (106 lb in). |
- Install a NEW EGR valve
pipe gasket.
- Position the EGR pipe.
- Install the EGR pipe bolts at the EGR adapter.
Tighten
Tighten the EGR pipe bolts to 30 N·m (22 lb ft).
- Connect the EGR valve
electrical connector (1).
- Install the bypass valve
vacuum hose (1) to the intake manifold.
- Position the engine harness
over the engine compartment.
- Connect the following electrical connectors:
• | Ignition coil harness (3) |
• | Purge valve solenoid (6) |
- Instal the CPA retainer at the ignition coil harness.
- Install the engine harness bolt and studs
Tighten
• | Tighten the engine harness bolt to 5 N·m (44 lb in). |
• | Tighten the engine harness stud to 10 N·m (89 lb in). |
- Connect the following
electrical connectors:
• | Ignition coil harness (2) |
- Install the CPA retainer at the ignition coil harness.
- Position engine harness
branch over the top of engine.
- Connect the following electrical connectors:
• | Pressure cycling switch (1) |
- Connect the engine harness clip to the wheelhouse splash shield.
- Connect the engine harness clips to the studs on the front of
dash.
- Connect the fuel feed
and return pipes. Refer to
Metal Collar Quick Connect Fitting Service
in Engine Controls - 8.1 L.
- Install the sight shield bracket (1) and nuts.
Tighten
Tighten the sight shield bracket nuts to 5 N·m (44 lb in).
- Install the sight shield to the bracket (1).
- Tighten the intake manifold sight shield bolt (3).
Tighten
Tighten the intake manifold sight shield bolt to 10 N·m
(89 lb in).
- Install the air cleaner
outlet duct.
- Tighten the clamps at the throttle body and air cleaner.
Tighten
Tighten the air cleaner outlet duct clamp to 4 N·m (35 lb in).