Removal Procedure
Important: You do not have to remove the upper intake manifold in order to remove
the lower intake manifold.
- Remove the engine cover.
Refer to
Engine Cover Replacement
in
Interior Trim.
- Disconnect the PCV tube from the air cleaner outlet duct.
- Remove the retaining nut (1)
from the air cleaner outlet .
- Remove the air cleaner outlet duct (2) from the throttle
body assembly.
- Disconnect the harness
connector of the intake air temperature (IAT) sensor .
- Loosen the air cleaner
outlet duct from the mass air flow (MAF) sensor.
- Remove the air cleaner outlet duct.
- Remove the air cleaner assembly. Refer to
Air Cleaner Assembly Replacement
in Engine Controls - 4.3L.
- Disconnect the accelerator control cable from the throttle shaft
and the accelerator control cable bracket. Refer to
Accelerator Control Cable Replacement
in Engine Controls
- 4.3L.
- Disconnect the cruise control cable, if equipped from the throttle
shaft and the accelerator control cable bracket. Refer to
Cruise Control Cable Replacement
in Cruise Control.
- Remove the PCV valve hose
assembly from the intake manifold and the valve rocker arm cover.
- Disconnect the following
electrical connectors:
• | The fuel meter body assembly connector (1) |
• | The EVAP canister purge solenoid valve (2) |
• | The manifold absolute pressure (MAP) sensor (3) |
- Disconnect the following
electrical connectors:
• | The throttle position (TP) sensor (1) |
• | The idle air control (IAC) motor (2) |
• | The engine coolant temperature (ECT) gauge sensor (3) |
• | The A/C high pressure switch (4), if equipped |
- Remove the engine wiring
harness bracket from the intake manifold stud.
- Move and secure the engine wiring harness out of the way.
- Disconnect the A/C vacuum
hose from the intake manifold.
- Remove the power brake booster vacuum hose bracket and nut from
the intake manifold stud.
- Disconnect the power brake booster vacuum hose from the intake
manifold.
- Remove the accelerator
control cable bracket from the throttle body and the intake manifold.
- Remove the EVAP canister purge solenoid. Refer to
Evaporative Emission Canister Purge Solenoid Valve Replacement
in
Engine Controls - 4.3L.
- Remove the fuel lines from the fuel meter body assembly. Refer
to
Fuel Hose/Pipes Replacement - Engine Compartment
in Engine Controls - 4.3L.
- Remove the distributor cap. Refer to
Distributor Replacement
in Engine Electrical.
- Remove the ignition control module. Refer to
Ignition Control Module Replacement
in Engine Electrical.
- Remove the studs for the
upper intake manifold.
- Remove the upper intake manifold.
- Remove the upper intake
manifold gasket from the groove.
- Discard the gasket.
- Remove the seal from the
fuel meter body assembly.
- Discard the seal.
Important: Do not immerse the assembled upper intake manifold in cleaning solvent.
- Clean all sealing surfaces and the inside of the upper intake manifold
with a shop towel and cleaning solvent.
- Inspect the upper intake manifold for the following:
• | Cracks or other damage to the exterior |
• | Cracking or damage to the gasket grooves |
• | Loose or damaged bolt hole thread inserts |
- If replacing the upper
intake manifold, turn and remove the power brake booster vacuum tube fitting
from the upper intake manifold.
- Remove and discard the seal.
- If replacing the upper
intake manifold, turn and remove the PCV valve cover from the upper intake
manifold.
- Remove and discard the seal.
- Remove the throttle body if replacing the upper intake manifold.
Refer to
Throttle Body Assembly Replacement
.
- Remove the MAP sensor if replacing the upper intake manifold.
Refer to
Manifold Absolute Pressure Sensor Replacement
in Engine Controls - 4.3L.
Installation Procedure
- Install the throttle body,
if removed. Refer to
Throttle Body Assembly Replacement
.
- Install the MAP sensor, if removed. Refer to
Manifold Absolute Pressure Sensor Replacement
in Engine
Controls - 4.3L.
- Install the PCV valve cover, if removed, using the following procedure:
3.1. | Install a NEW seal (O-ring) on the PCV valve cover. |
3.2. | Lubricate the seal with clean engine oil. |
3.3. | Install the PCV valve cover in the upper intake manifold. |
3.4. | Turn and lock the PCV valve cover in position. |
- Install the power brake
booster vacuum tube fitting, if removed, using the following procedure:
4.1. | Install a NEW seal (O-ring) on the power brake booster vacuum
tube fitting. |
4.2. | Lubricate the seal with clean engine oil. |
4.3. | Install the power brake booster vacuum tube fitting in the upper
intake manifold. |
4.4. | Turn and lock the power brake booster vacuum tube fitting in
position. |
- Install a NEW seal on
the fuel meter body assembly.
- Lubricate the seal with clean engine oil.
- Install a NEW upper intake
manifold to lower intake manifold gasket in the groove of the upper intake
manifold.
- Install the upper intake
manifold onto the lower intake manifold.
- If reusing the fasteners, apply threadlock GM P/N 12345382
or equivalent to the threads of the upper intake manifold attaching bolts.
Notice: Use the correct fastener in the correct location. Replacement fasteners
must be the correct part number for that application. Fasteners requiring
replacement or fasteners requiring the use of thread locking compound or sealant
are identified in the service procedure. Do not use paints, lubricants, or
corrosion inhibitors on fasteners or fastener joint surfaces unless specified.
These coatings affect fastener torque and joint clamping force and may damage
the fastener. Use the correct tightening sequence and specifications when
installing fasteners in order to avoid damage to parts and systems.
- Install the upper
intake manifold attaching studs.
Tighten
- Tighten the upper intake manifold attaching studs on the first
pass to 5 N·m (44 lb in).
- Tighten the upper intake manifold attaching studs on the final
pass to 9 N·m (80 lb in).
- Install the fuel lines to the fuel meter body assembly. Refer
to
Fuel Hose/Pipes Replacement - Engine Compartment
in Engine Controls - 4.3L.
- Install the distributor cap. Refer to
Distributor Replacement
in Engine Electrical.
- Install the ignition control module. Refer to
Ignition Control Module Replacement
in Engine Electrical.
- Install the EVAP canister purge solenoid valve. Refer to
Evaporative Emission Canister Purge Solenoid Valve Replacement
in Engine Controls - 4.3L.
- Install the accelerator
control cable bracket, studs, and nuts to the intake manifold and the throttle
body.
Tighten
Tighten the accelerator control cable bracket nuts and studs to 12 N·m
(106 lb in).
- Connect the A/C vacuum
hose to the intake manifold.
- Install the power brake booster vacuum hose bracket and nut to
the intake manifold stud.
Tighten
Tighten the power brake booster vacuum hose bracket nut to 11 N·m
(97 lb in).
- Connect the power brake booster vacuum hose to the intake manifold.
- Install the bracket for
the engine wiring harness on the lower intake manifold stud.
- Instal the engine wiring harness bracket nut.
Tighten
Tighten the engine wiring harness bracket nut to 12 N·m
(106 lb in).
- Connect the following
electrical connectors:
• | The fuel meter body assembly connector (1) |
• | The EVAP canister purge solenoid valve (2) |
• | The manifold absolute pressure (MAP) sensor (3) |
- Connect the following
electrical connectors:
• | The throttle position (TP) sensor (1) |
• | The idle air control (IAC) motor (2) |
• | The engine coolant temperature (ECT) gauge sensor (3) |
• | The A/C high pressure switch (4), if equipped |
- Connect the PCV valve
hose assembly to the intake manifold and the valve rocker arm cover.
- Install the cruise control cable, if equipped to the throttle
shaft and the accelerator control cable bracket. Refer to
Cruise Control Cable Replacement
in Cruise Control.
- Install the accelerator control cable to the throttle shaft and
the accelerator control cable bracket. Refer to
Accelerator Control Cable Replacement
in Engine Controls - 4.3L.
Notice:
• | Handle the MAF sensor carefully. |
• | Do not drop the MAF sensor in order to prevent damage to the MAF
sensor. |
• | Do not damage the screen located on the air inlet
end of the MAF. |
• | Do not touch the sensing elements. |
• | Do not allow solvents and lubricants to come in contact with the
sensing elements. |
• | Use a small amount of a soap based solution in order to aid in
the installation. |
- Install the
air cleaner outlet duct to the MAF sensor.
- Connect the IAT sensor
harness connector.
- Install the air cleaner
outlet duct (2) on the throttle body assembly.
- Tighten the retaining nut (1).
Tighten
Tighten the nut 2 N·m (18 lb in).
- Connect the PCV tube to the air cleaner outlet duct.
- Install the air cleaner. Refer to
Air Cleaner Assembly Replacement
in Engine Controls - 4.3L.
- Install the engine cover. Refer to
Engine Cover Replacement
in Interior Trim.