GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 716
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.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 719
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.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 720
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.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 726
RELIEVING FUEL SYSTEM PRESSURE
1. Remove the fuse marked "Fuel Pu mp" from the fuse block in the
passenger compartment.
2. Crank the engine. Th e engine will start and run until the fuel supply
remaining in the lines is exhauste d. When the engines stops, engage the
starter again for three seconds to a ssure dissipation of any remaining
pressure.
3. With the ignition OFF, disconnect the negative battery cable to prevent
fuel discharge if the key is accidentally turned to the ON position.
Replace the fuse with the ignition OFF.
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 removal and installation procedures fo r the Crossfire injection system fuel
pump is identical to the Throttle Body In jection (TBI) system. Please refer to the
TBI fuel pump procedures earlier in this repair guide.
TESTING
The testing procedures for the Crossfire in jection system fuel pump is identical
to the Throttle Body Injection (TBI) syst em. Please refer to the TBI fuel pump
procedures earlier in this repair guide.
THROTTLE BODY
REMOVAL & INSTALLATION
FRONT UNIT
1. Relieve the fuel system pressure.
2. Remove the air cleaner assembly, noting the connection points of the
vacuum lines.
3. Detach the electrical connectors at the injector and the idle air control
motor.
4. Disconnect the vacuum lines from the TBI unit, noting the connection
points. During installation, refer to the underhood emission control
information decal for vacuum line routing information.
5. Disconnect the transmission det ent cable from the TBI unit.
6. Disconnect the fuel inlet (feed) and fuel balance line connections at the
front TBI unit.
7. Remove and discard the throttle cont rol rod retaining clip from the front
TBI throttle lever stud. A new clip must be used during reassembly.
8. Unbolt and remove the TBI unit.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 732
MINIMUM IDLE AND THROTTL
E VALVE SYNCHRONIZING
The throttle position of each throttle body must be balanced so that the throttle
plates are synchronized and open si multaneously. These adjustment
procedures must be followed AFTER performing the "Preliminary Adjustments".
1. Remove the air cleaner and plug the vacuum port on the rear TBI unit for
the thermostatic air cleaner.
2. Remove the tamper resistant pl ugs covering both unit throttle stop
screws, if necessary.
3. Block the drive wheels and apply the parking brake.
4. Connect a tachometer to measure rpm.
5. Start the engine and allo w the engine rpm to stabilize at normal operating
temperature.
6. Have a helper apply the brakes and place the transmission in DRIVE.
7. Plug the idle air pass ages of each throttle body with plugs (J-33047 or
equivalent). Make sure the plugs are seated fully in the passage so that
no air leaks exist. The engine rpm should decrease below curb idle
speed. If the engine rpm does not decreas e, check for a vacuum leak.
8. Remove the cap from the ported tube on the rear TBI unit and connect a
vacuum gauge or water manometer.
9. Adjust the rear unit throttle stop screw to obtain approximately
1/2 in. Hg
as read on the vacuum gauge, or 6 in. H
2O as read on the manometer. If
not able to adjust to this level, check that the front unit throttle stop is not
limiting throttle travel.
10. Remove the vacuum gauge or manometer from t he rear unit and install
the cap on the port ed vacuum tube.
11. Remove the cap from the ported va cuum tube on the front TBI unit and
install the gauge or manomet er as before. If the reading is not the same
as the rear unit, proceed as follows: a. Locate the throttle synchronizing screw and collar on the front TBI
unit. The screw may be welded to discourage tampering with this
adjustment. Break the weld, if ne cessary, and install a new screw
with a thread seali ng compound applied.
b. Adjust the screw to obtain approximately
1/2 in. Hg as read on the
vacuum gauge, or 6 in. H
2O on the manometer.
12. Remove the gauge or manometer fr om the ported tube and reinstall the
cap.
13. Adjust the rear throttle stop screw to obtain 475 rpm, with the
transmission in D and the parking brake applied. On manual
transmission models, leave the gear selector in N.
14. Turn the ignition OFF and pl ace automatic transmission in N.
15. Remove idle air passage plugs.
16. Start the engine. It may run at a high rpm but the engine speed should
decrease when the idle air control va lves close the air passages. Stop
the engine when the rpm decreases.
17. The throttle position sensor (TPS) voltage should be checked and adjusted, if necessary.
18. Connect the vacuum line to the TBI unit and install the air cleaner.
19. Reset the idle speed control motors by driving the vehicle to 45 mph.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 735
Fig. 2: IAC valve installation
MULTI-PORT FUEL INJECTION SYSTEMS
SYSTEM DESCRIPTIONS
The Multi-Port Fuel Injection (MPFI or MFI) systems were first introduced on the
1985 models. They may be called different names (Port Fuel Injection-PFI,
Tuned Port Injection-TPI, Sequential Fuel Injection-SFI), however, all of the
systems are similar in operation.
The systems are controlled by an Elec tronic Control Module (ECM) which
monitors the engine operations and gen erates output signals to provide the
correct air/fuel mixture, ignition timing and idle speed. Input information to the
ECM is provided by the oxygen sens or, temperature sensors, detonation
sensor, mass air flow sensor and throttle position sensor. A system may use all
or some of these sensors, depending on the year and engine application. The
ECM also receives information concerning engine rpm, road speed,
transmission gear position, power steer ing and air conditioning status.
All of the systems use multiple injector s, aimed at the intake valve at each
intake port, rather than the centrally lo cated injector(s) found on the earlier
Throttle Body Injection (TBI) and Crossfir e Injection systems. The injectors are
mounted on a fuel rail and ar e activated by a signal from the electronic control
module. The injector is a solenoi d-operated valve which remains open
depending on the width of t he electronic pulses (length of the signal) from the
ECM; the longer the open time, the more f uel is injected. In this manner, the
air/fuel mixture can be precisely c ontrolled for maximum performance with
minimum emissions.
There are two different types of f uel management systems used on the multi-
port fuel injection engines. The mass air flow system and the speed density
system.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 739
3. Make sure the ignition switch has
been in the OFF position for at least 10
seconds and that all accessories are OFF.
4. Turn the ignition switch ON and the pump will run for about 2 seconds.
Note the system pressure with t he pump running, it should be between
40-47 psi.
The ignition switch may have to be cycled to the ON position more than once to
obtain maximum pressure. It is also norma l for the pressure to drop slightly
when the pump first stops, but it should then hold steady.
5. If the pressure is not as specified, verify that fuel pump operation is
heard in the tank.
6. If fuel pump operation is not heard, inspect the fuel pump relay and
wiring.
7. If fuel pump operation is heard, inspect the filter and lines for restriction.
8. Start the engine and make sure the pr essure decreases about 3-10 psi at
idle.
9. If fuel pressure does not decrease, inspect the fuel pressure regulator
and hose.
10. Disconnect the fuel pressure gauge.
THROTTLE BODY
REMOVAL & INSTALLATION 1. Disconnect the negative (-) battery c able and partially drain the radiator.
2. Remove the air inlet duct and unplug the IAC and TPS electrical connectors.
3. Label and disconnect the vacuum and coolant lines.
4. Disconnect the accelerator, thro ttle valve (transmission control) and
cruise control cables, as applicable.
5. Remove the throttle body attaching bolts, then separate the throttle body from the plenum.
6. Discard the gasket.
To install: 7. Install the throttle body to the plenum using a new gasket. Tighten the \
bolts to specification.
8. Engage the accelerator, throttle valve and cruise control cables, as
necessary. Make sure that the link ages do not hold the throttle open.
9. Connect the vacuum and coolant lines.
10. Install the air inlet duct and plug the IAC and TPS electrical connectors
into their sockets.
11. Connect the negative (-) battery cable and refill the radiator.
12. With the engine OFF, check to s ee that the accelerator pedal is free.
Depress the pedal to the floor and release.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 761
MAINTENANCE OR REPAIR?
Maintenance includes routine inspecti
ons, adjustments, and replacement of
parts which show signs of normal wear . Maintenance compensates for wear or
deterioration. Repair implies that someth ing has broken or is not working. A
need for a repair is often caused by lack of maintenance. for example: draining
and refilling automatic transmission fl uid is maintenance recommended at
specific intervals. Failure to do this can shorten the life of the
transmission/transaxle, requiring very expen sive repairs. While no maintenance
program can prevent items from eventually breaking or wearing out, a general
rule is true: MAINTENANCE IS CHEAPER THAN REPAIR.
Two basic mechanic's rules should be mentioned here. First, whenever the left
side of the vehicle or engine is refe rred to, it means the driver's side.
Conversely, the right side of the vehi cle means the passenger's side. Second,
screws and bolts are removed by turn ing counterclockwise, and tightened by
turning clockwise unless specifically noted.
Safety is always the most important rule. Constantly be aware of the dangers
involved in working on an automobile and take the proper precautions. Please
refer to the information in this se ction regarding SERVICING YOUR VEHICLE
SAFELY and the SAFETY NOTICE on the acknowledgment page.
AVOIDING THE MOST COMMON MISTAKES
Pay attention to the instructions prov ided. There are 3 common mistakes in
mechanical work:
1. Incorrect order of assembly, di sassembly or adjustment. When taking
something apart or putting it toget her, performing steps in the wrong
order usually just costs you ex tra time; however, it CAN break
something. Read the entire proc edure before beginning. Perform
everything in the order in which the instructions say you should, even if
you can't see a reason for it. When you' re taking apart something that is
very intricate, you might want to draw a picture of how it looks when
assembled in order to make sure you get everything back in its proper
position. When making adjustments, per form them in the proper order.
One adjustment possibly will affect another.
2. Overtorquing (or undertorquing). While it is more common for overtorquing to cause damage, undertorquing may allow a fastener to
vibrate loose causing serious dam age. Especially when dealing with
aluminum parts, pay attention to tor que specifications and utilize a torque
wrench in assembly. If a torque figure is not available, remember that if
you are using the right tool to perfo rm the job, you will probably not have
to strain yourself to get a fast ener tight enough. The pitch of most
threads is so slight that the te nsion you put on the wrench will be
multiplied many times in actual fo rce on what you are tightening.
There are many commercial products avai lable for ensuring that fasteners won't
come loose, even if they are not torqued just right (a very common brand is