CHEVROLET CAMARO 1982 Repair Guide

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 711
THROTTLE BODY INJECTION SYSTEM

SYSTEM DESCRIPTION
The throttle body injection (TBI) system used on 2.5L (VIN 2) and 5.0L (VIN E)
engines is centrally located
on the intake manifold. Its function is to supply the
correct air/fuel mixture to the engine, as directed by the Engine Control Module
(ECM).
The TBI unit consists of two relatively simple casting assemblies: a throttle body
and a fuel metering assembly. Components include, a pressure regulator, idle
air control valve, fuel injector(s), thro ttle position sensor, fuel inlet and a fuel
return fitting.
The Throttle Body Injection identifi cation number is stamped on the lower
mounting flange located near the TPS. Th e number is in alphabetical code and
should be noted before servicing the unit.
An oxygen sensor in the exhaust syst em functions to provide feedback
information to the ECM as to oxygen content in the exhaust. The ECM then
uses this information to modify fuel de livery to achieve as near as possible an
ideal air/fuel ratio of 14.7 :1. This ratio permits the ca talytic converter to become
more effective in reducing emissions wh ile providing acceptable driveability.
Should you encounter any type of engine performance problem, have a
complete CCC system test performed by a qualified, professional technician. If
the fault lies in the injection system, you can use the following procedures to
remove the TBI unit and replace the defective component(s).
RELIEVING FUEL SYSTEM PRESSURE
1. Disconnect the negative battery cable to prevent fuel discharge if the key
is accidentally turned to the RUN position.
2. Loosen the fuel filler cap to relieve fuel tank pressure and do not tighten
until service has been completed.
3. Fuel system pressure is automatic ally relieved when the engine is turned
OFF. No further action is necessary.
When disconnecting fuel lines, there ma y still be a small amount of fuel
released. Cover the fuel line connection wi th a shop cloth to collect the fuel,
then place the cloth in an approved container.
ELECTRIC FUEL PUMP
REMOVAL & INSTALLATION
The fuel pump is part of t he fuel sender assembly located inside the fuel tank.
1. Release the fuel syst em pressure and disconnec t the negative battery
cable.

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2. Drain the fuel tank, then raise
and safely support the vehicle.
3. Remove the fuel tank from the vehicle.
4. Clean the area surrounding t he sender assembly to prevent
contamination of the fuel system.
5. Remove the fuel sender fr om the tank as follows:
a. Use tool J-24187 or equivalent to remove the sending unit
retaining cam. Remove the fuel sender and O-rings from the tank.
Discard the O-rings.
6. If necessary, separate the fuel pum p from the sending unit assembly.
To install: 7. If removed, install the fuel pump to the sending unit. If the strainer was
removed, it must be re placed with a new one.
8. Inspect and clean the O-ring mating surfaces.
9. Install a new O-ring in the groove around the tank opening. If applicable,
install a new O-ring on t he fuel sender feed tube.
10. Install the fuel sender assembly as follows: a. The fuel pump strainer must be in a horizontal position, and when
installed, must not block the travel of the float arm. Gently fold the
strainer over itself an d slowly position the sending assembly in the
tank so the strainer is not dam aged or trapped by the sump walls.
11. Install the retaining cam us ing tool J-24187 or equivalent.
12. Install the fuel tank assembly.
13. Lower the vehicle.
14. Fill the fuel tank, tighten the f uel filler cap and connect the negative
battery cable.

Fig. 1: Fuel pump and sending unit assembly

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Fig. 2: Fuel pump locking cam tool
TESTING 1. Turn the engine OFF and relieve the fuel pressure.
2. Remove the air cleaner and plug the THERMAC vacuum port on TBI.
3. Install a fuel pressure gauge between the throttle body unit and the fuel line. Use a back-up wrench to hold fuel nut on the TBI when removing
the fuel line.

Fig. 3: Fuel pressure can be check ed using an inexpensive pressure/vacuum
gauge

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4. Start the car and observe the fuel
pressure reading. It should be 9-13 psi
(62-90 kPa).
5. Relieve the fuel pressure.
6. Remove the fuel pressure gauge.
7. Reinstall the fuel line.
8. Start the car and che ck for fuel leaks.
9. Remove plug covering THERMAC va cuum port on the TBI and install the
air cleaner.
THROTTLE BODY
REMOVAL & INSTALLATION 1. Relieve the fuel system pressure.
2. Disconnect the THERMAC hose from the engine fitting and remove the
air cleaner.
3. Detach the electrical connectors at the idle air control, throttle position
sensor, and the injector.
4. Disconnect the throttle linkage, re turn spring, and cruise control (if
equipped).
5. Disconnect the throttle body vacuum hoses, fuel supply and fuel return
lines.
6. Disconnect the 3 bolts securing the throttle body and remove the throttle
body.
7. To install, reverse the removal procedures. Replace the manifold gasket
and O-rings.
8. Perform the minimum idle speed adjustment, if necessary.

Fig. 1: Single injector TBI unit

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Fig. 2: Dual injector TBI unit

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INJECTOR REPLACEMENT
Use care in removing injectors to prev
ent damage to the electrical connector
pins on top of the injector, the fuel injector fuel filter and nozzle. The fuel injector
is serviced as a complete assembly on ly and should never be immersed in any
type of cleaner.
SINGLE INJECTOR UNITS 1. Relieve the fuel system pressure.
2. Remove the air cleaner.
3. Detach the injector connector by squeezing the two tabs together and
pulling straight up.
4. Remove the screws securing the fuel meter cover. Note the location of
any short screws for correct placement during reassembly.
CAUTION - DO NOT remove the four screws se curing the pressure regulator to
the fuel meter cover. The fuel pressure regulator includes a large spring under
heavy tension which could cause personal injury if released.
5. With the old fuel meter gasket in place to prevent damage to the casting,
use a prytool and fulcrum to pry the inje ctor carefully until it is free from
the fuel meter body.
6. Remove the injector.
7. Remove the large O-ring and steel back-up washer at the top of the
injector cavity in the fuel meter body.
8. Remove the small O-ring located at the bottom of the injector cavity.
To Install: 9. Lubricate the new, small O-ring with automatic transmission fluid; then,
push the new O-ring on the nozzle end of the injector up against the
injector fuel filter.
10. Install the steel backup washer in the recess of the fuel meter body.
Lubricate the new large O-ring with automatic transmission fluid, then
install the O-ring directly above t he backup washer, pressing the O-ring
down into the cavity recess. The O-ri ng is properly installed when it is
flush with the casting surface.
WARNING - Do not attempt to reverse this procedure and install the backup
washer and O-ring after the injector is located in the cavity. To do so will
prevent proper seating of the O-ring in th e cavity recess which could result in a
fuel leak and possible fire.
11. Install the injector by using a pushing/twisting mo tion to center the nozzle
O-ring in the bottom of the injector cavity and aligning the raised lug on
the injector base with the notch cast into the fuel meter body. Push down
on the injector making sure it is fully seated in the cavity. Injector
installation is correct when the lug is seated in the notch and the
electrical terminals are parallel to the throttle shaft.

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12. Using new gaskets on the fuel mete
r cover and a new dust seal, install
the cover to the fuel meter body . The two short screws are located
adjacent to the injector.
13. Connect the injector electrical c onnector by pushing straight down until
seated firmly in place.
14. Connect the negative battery cable.
15. With the engine OFF and the igniti on ON, check for fuel leaks.
16. Install the air cleaner.

Fig. 3: Removing the fuel injectors

Fig. 4: Fuel injector components

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Fig. 5: Installing the fuel injectors
DUAL INJECTOR UNITS 1. Relieve the fuel system pressure.
2. Remove the air cleaner.
3. Disconnect the injector connector by squeezing the two tabs together and pulling straight up.
4. Remove the screws securi ng the fuel meter cover.
CAUTION - DO NOT remove the four screws securing the pressure regulator to
the fuel meter cover. The fuel pressure regulator includes a large spring under
heavy tension which could cause personal injury if released.
5. With the old fuel meter gasket in pl ace to prevent damage to the casting,
use a suitable prytool and fulcrum to pr y the injector carefully until it is
free from the fuel meter body.
6. Remove the injector.
7. Remove the small O-ring from the nozzle end of the injector and discard
it.
8. Remove the old fuel meter cover gasket and discard it.
9. Remove the upper O-ring and steel ba ckup washer from the top of the
injector cavity. Discard the O-ring.
To install: 10. Install the steel backup washer in t he counterbore of the fuel meter body.

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11. Lubricate the new large O-ring with cl
ean engine oil and install it directly
over the backup washer. Be sure t he O-ring is seated properly and is
flush with the top of the fuel meter body surface.
12. Lubricate the new small O-ring with clean engine oil and install it on the
nozzle end of the injector. Push t he O-ring on far enough to contact the
filter.
WARNING - Do not attempt to reverse this procedure and install the backup
washer and O-ring after the injector is located in the cavity. To do so will
prevent proper seating of the O-ring in th e cavity recess which could result in a
fuel leak and possible fire.
13. Install the injector by aligning the raised lug on the injector base with the
notch cast into the fuel meter body . Push down on the injector making
sure it is fully seated in the cavity. In jector installation is correct when the
lug is seated in the notch and the electrical terminals are parallel to the
throttle shaft.
14. Using new gaskets on the fuel mete r cover and a new dust seal, install
the cover to the fuel meter body. Use an appropriate thread locking
compound on the cover attaching screws.
15. Connect the injector electrical c onnector by pushing straight down until
seated firmly in place.
16. Connect the negative battery cable.
17. With the engine OFF and the igniti on ON, check for fuel leaks.
18. Install the air cleaner.
ADJUSTMENTS
MINIMUM IDLE SPEED
Minimum idle speed should only be adjus ted when installing a replacement
throttle body. The idle stop screw is used to regulate the minimum idle speed of
the engine. The throttle body is adjusted at the factory, then covered with a cap
or plug to discourage unnecessary readjustment.
2.5L ENGINES 1. Remove the air cleaner and pl ug the THERMAC vacuum port.
2. Disconnect the TV cable from the th rottle control bracket to allow access
to the idle adjustment screw.
3. Remove the throttle stop screw plug or cap.
4. Connect a tachometer to the engine.
5. Disconnect the Idle Air Control (IAC) valve connector.
6. Start the engine with the transmi ssion in PARK (auto transmission) or
NEUTRAL (manual transmission) and allow the engine speed to
stabilize. All accessories (A/C, rear defogger, etc.) should be OFF.
7. Install tool J-33047 in t he idle air passage of the throttle body. Be certain
that the tool seats fully in t he passage and no air leaks exist.

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8. Using a number 20 Torx® bit, turn
the throttle stop screw until the engine
speed is 475-525 rpm in PARK (aut o transmission) or 450-500 rpm in
NEUTRAL (manual transmission).
9. Stop the engine and remove tool J-33047 from the throttle body.
10. Reconnect the TV cable to the throttle control bracket.
11. Reconnect the IAC valve connector.
12. Use silicone sealant to co ver the throttle stop screw.
13. Reinstall the air cleaner.

Fig. 6: Installing tool J-33047
5.0L ENGINES 1. Remove the idle stop screw plug or cap.
2. Ground the diagnostic connector (ALDL).
3. Turn the ignition ON and wait 45 seconds, DO NOT start the engine.
4. Disconnect the idle air control connector with the ignition ON.
5. Remove the ground from the di agnostic connector and disconnect the
distributor set-timing connector.
6. Connect a tachometer to the engine.
7. Place the transmission in PARK (auto transmission) or NEUTRAL
(manual transmission). Start and run the engine until it reaches normal
operating temperature.
It is important that the distributor set- timing connector be disconnected to fix the
spark advance at base timing. This elim inates the possibility of changes in
engine speed due to variations in timing.