1982 CHEVROLET CAMARO Repair Guide

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 729
17. Check the throttle position sensor voltage and adjust if necessary.
18. Perform the Minimum Idle and Thro
ttle Valve Synchronization adjustment
procedures.
INJECTOR REPLACEMENT
The removal and installation procedures fo r the Crossfire injection system's fuel
injector is identical to the Throttle Bo dy Injection (TBI) system. Please refer to
the TBI fuel injector procedures earlier in this repair guide.
ADJUSTMENTS
PRELIMINARY ADJUSTMENTS
The preliminary adjustments are performed if tampering with the idle speed or
synchronization is evident and when either of the throttle bodies or the manifold
cover have been replaced. They must be performed BEFORE the Minimum Idle
and Throttle Valve Synchronizing procedure.
THROTTLE VALVE SYNCHRONIZING
1. Turn BOTH front and rear unit throttle stop screws counterclockwise enough to break contact with the related throttle lever tangs.
2. Adjust the throttle synchronizing scr ew to allow BOTH throttle valves to
close. The throttle rod end bearing w ill move freely on the front unit
throttle lever stud when both valves are closed.
3. Turn the front unit th rottle stop screw clockwise slowly until it makes
contact with the throttle lever tang. Turn the screw clockwise an
additional
1/4 turn.
4. Turn the rear unit throttle stop screw clockwise slowly until it makes
contact with the throttle lever t ang. Turn the screw an additional
1/2 turn.

Fig. 1: Blocking the throttle levers

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 730

Fig. 2: Throttle stop and synchronizing screws
THROTTLE ROD ALIGNMENT CHECK
The throttle rod alignment check procedur e is followed only if a replacement
manifold cover or TBI unit has been inst alled. If not, proceed to "Minimum Idle
and Throttle Valve Synchronizing".
1. Actuate the rear unit throttle leve r to bring both units to the wide open
throttle position, loading the throttle valves. Move the throttle rod toward
the front unit casting boss.
2. Check the clearance bet ween the shoulder of the stud and the side of the
ball surface. Maximum clearance must not exceed 0.200 in. (5mm). If the
clearance is greater, the assembly (mani fold cover, TBI unit or throttle
body) must be replaced and the pr eliminary adjustments repeated.
3. Use needle-nose pliers to inst all a NEW throttle rod and bearing
assembly retaining clip.
4. Move both front and rear throttle le vers through the total throttle travel,
loading both valves.
5. Check the clearance bet ween the throttle rod and the front unit throttle
body casting boss. If minimum clearanc e is less than 0.040 in. (1.02mm),
the assembly must be replaced. If minimum clearance is at least 0.040
in. (1.02mm), proceed with assembly.

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Fig. 3: Maximum shoulder-to-ball clearance check

Fig. 4: Minimum throttle r od-to-casting clearance check

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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.

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THROTTLE POSITION SENSOR (TPS)
An accurate digital voltmeter is
needed to perform this adjustment.
1. Remove the air cleaner.
2. Disconnect the TPS electrical connector.
3. Install three jumper wires betwe en the TPS and the TPS wiring terminal
connections.
4. Turn the ignition ON, engine stopped, measure the voltage between
terminals B and C.
5. The display should read between 0.45-0.60 volts.
6. Loosen the screws and rotate the TPS to obtain the correct voltage, if necessary.
7. Tighten the TPS screws and turn the i gnition OFF. Remove the jumpers.
8. Reconnect the wir ing to the TPS.
9. Install the air cleaner.

Fig. 5: TPS adjustment
FUEL PRESSURE REGULATOR
REMOVAL & INSTALLATION
The removal and installation procedures fo r the Crossfire injection system's fuel
pressure regulator is identical to t he Throttle Body Injection (TBI) system.
Please refer to the TBI fuel pressure r egulator procedures earlier in this repair
guide.
THROTTLE POSITION SENSOR (TPS)
REMOVAL & INSTALLATION
1. Remove the air cleaner.
2. Disconnect the electrical connector.
3. Remove the TPS attaching screws and lockwashers.
4. Remove the TPS.
To install:

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 734
5. Install the throttle position sensor
. Make sure the TPS pickup lever is
located above the tang on the throttle actuator lever.
6. Install the TPS attaching screws.
7. Adjust the TPS voltage.
8. Reconnect the electrical connector.
9. Install the air cleaner.
IDLE AIR CONTROL VALVE
REMOVAL & INSTALLATION 1. Remove the air cleaner.
2. Detach the electrical connection fr om the idle air control assembly.
3. Using a 1
1/4 in. wrench, remove the IAC valve from the throttle body. On
IAC valves secured with screws, remove the attaching screws.
Before installing a NEW IAC valve, measur e the distance that the conical valve
is extended. Measurement should be made from the motor housing to the end
of the cone. Distance s hould be no greater than 1
1/4 in. (32mm). If the cone is
extended too far, damage may result when the motor is installed. If necessary,
push on the end of cone until it is retracted the correct distance.
4. Installation is the reverse of remo val. Torque threaded valves to 13 ft.
lbs. (17 Nm).

Fig. 1: IAC valve pintle measurement

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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) 736
The mass air flow systems measure the
mass of air that is drawn into the
engine cylinders, rather than just the vo lume. The sensor contains a hot-wire
sensing unit, which is made up of an electronic balanced bridge network.
Whenever current is suppli ed to the sensor, the bridge is energized and the
sensing hot-wire is heated. As the air enter s the mass air flow sensor, it passes
over and cools the hot wire. When the hot wire is cooled, it's resistance changes
and additional current is needed to k eep the bridge network balanced. This
increase in current is sent to the computer as a voltage signal and is used to
calculate the mass of the incoming air. The ECM uses this information to\

determine the duration of fuel injection pulse, ignition timing and EGR operation.
The speed density systems calculate the volume of air moving through the
intake. The ECM establishes the speed fact or through a signal from the ignition
module. The Manifold or Intake Air Temperature (MAT/IAT) and the Engine
Coolant Temperature (ECT) sensors work together to assure that proper
temperature information gets to the ECM wh ile the Manifold Absolute Pressure
(MAP) sensor monitors the changes in m anifold pressure which results from
changes in engine loading. These three se nsors contribute to the density factor.
Together, these inputs (engine speed, coolant temperature sensor, etc ...) are
the major determinants of the air/fuel mixture delivered by the fuel injection
system.
The following engines and fuel managem ent systems are covered in this
section:
• 1985-1989 2.8L MPFI - Mass Air Flow
• 1990-1992 3.1L MPFI - Speed Density
• 1985-1989 5.0L and 5.7L TPI - Mass Air Flow
• 1990-1992 5.0L and 5.7L TPI - Speed Density
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 reliev e the tank pressure and do not tighten
until service has been completed.
3. Connect J-34730-1 fuel pressure gauge or equivalent, to the fuel
pressure test valve. Wrap a shop towel around the fitting while
connecting the gauge to prevent spillage.
4. Place the end of the bleed hose into a suitable container and open the
valve to relieve the fuel system pressure.
ELECTRIC FUEL PUMP
REMOVAL & INSTALLATION
The fuel pump is part of t he fuel sender assembly located inside the fuel tank.