GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 48
BRAKES
BASIC OPERATING PRINCIPLES
Hydraulic systems are used to actuate t he brakes of all modern automobiles.
The system transports the power required to force the frictional surfaces of the
braking system together from the pedal to the individual brake units at each
wheel. A hydraulic system is used for two reasons.
First, fluid under pressure can be carried to all parts of an automobile by small
pipes and flexible hoses without taking up a significant amount of room or
posing routing problems.
Second, a great mechanical advantage can be given to the brake pedal end of
the system, and the foot pressure requi red to actuate the brakes can be
reduced by making the surface area of t he master cylinder pistons smaller than
that of any of the pistons in t he wheel cylinders or calipers.
The master cylinder consists of a flui d reservoir along with a double cylinder
and piston assembly. Double type master cylinders are designed to separate
the front and rear braking systems hydraulic ally in case of a leak. The master
cylinder coverts mechanical motion from t he pedal into hydraulic pressure within
the lines. This pressure is translated back into mechanical motion at th\
e wheels
by either the wheel cylinder (drum brak es) or the caliper (disc brakes).
Steel lines carry the brake fluid to a po int on the vehicle's frame near each of
the vehicle's wheels. The fluid is then ca rried to the calipers and wheel cylinders
by flexible tubes in order to allow for suspension and steering movements.
In drum brake systems, each wheel cylinde r contains two pistons, one at either
end, which push outward in opposite direct ions and force the brake shoe into
contact with the drum.
In disc brake systems, the cylinders ar e part of the calipers. At least one
cylinder in each caliper is used to fo rce the brake pads against the disc.
All pistons employ some type of seal, us ually made of rubber, to minimize fluid
leakage. A rubber dust boot seals the outer end of the cylinder against dust and
dirt. The boot fits around the outer end of the piston on disc brake calipers, and
around the brake actuating rod on wheel cylinders.
The hydraulic system operates as follows : When at rest, the entire system, from
the piston(s) in the master cylinder to t hose in the wheel cylinders or calipers, is
full of brake fluid. Upon app lication of the brake pedal, fluid trapped in front of
the master cylinder piston(s) is forced through the lines to the wheel cylinders.
Here, it forces the pistons outward, in the case of drum brakes, and inward
toward the disc, in the case of disc brakes. The motion of the pistons is
opposed by return springs mounted outside the cylinders in drum brakes, and
by spring seals, in disc brakes.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 147
SYSTEM OPERATION
The main portions of the SIR system
are the deployment loops and the
Diagnostic Energy Reserve Module (D ERM). The main function of the
deployment loops is to supply current through the inflator module(s), which will
cause deployment of the air bag(s) in t he event of a frontal crash of sufficient
force. The arming sensor, SIR coil assembly (driver side only), passen\
ger
inflator module jumper (passenger side only), inflator module(s), passenger
compartment discriminating sensor and fo rward discriminating sensor make up
the deployment loops.
The DERM has two functions. One to supply the deployment loops with a 36
volt reserve to ensure sufficient energy is available to deploy the airbag(s) if the
battery voltage feed to the arming sensor is lost during a frontal crash. Another
function is SIR electrical system diagnostics.
The arming sensor switches power to th e inflator module(s) on the high side
(power side) of the deployment loops. Ei ther of the discriminating sensors can
supply ground to the inflator module(s) on the low side (ground side) of the loop.
The inflator module(s) ar e only supplied sufficient cu rrent to deploy when the
arming sensor and at least one of the two discriminating sensors are closed
simultaneously.
SYSTEM COMPONENTS
DIAGNOSTIC ENERGY RESERVE MODULE
The DERM is designed to perform the following functions in the SIR system:
• Energy Reserve - Maintains 36 volt energy reserve(s) to provide
deployment energy when the vehicle volt age is low or lost in a frontal
impact
• Malfunction Detection - Performs diagnostic monitoring of the SIR
system electrical components
• Malfunction Recording - Provides diagnostic trouble code information
• Frontal Crash Recording - Record s the SIR system status during a
frontal crash
WARNING LAMP
The "INFL REST" or "AIR BAG" warning lamp is used to do the following:
• Verify lamp and DERM oper ation by flashing seven to nine times when
the ignition key is first turned ON
• Warn the driver of SIR electrical system faults which could potentially
affect the operation of the SIR system
• Provide diagnostic information by fl ashing the fault codes when the
diagnostic mode is enabled
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 289
6. Make sure that levers L, M, and N
are in their Neutral positions (center
detents).
7. Align the holes of levers E, H, and J with the notch in the shifter
assembly (G). Insert an alignment gauge (J-33195) to hold the levers in
this position.
8. Insert swivel S into lever E and insta ll washer Q. Secure with retainer P.
9. Apply rearward pressure (Z) to leve r N. Tighten locknuts R and T (at the
same time) against swivel S to 25 ft. lbs. (34 Nm).
10. Repeat steps 8 and 9 for rod D and levers J and M.
11. Repeat steps 8 and 9 for rod K and levers H and L.
12. Remove the alignment gauge, lower t he vehicle, and check the operation
of the shifting mechanism.
13. Reconnect the negative battery cable.
CLUTCH SWITCH
REMOVAL & INSTALLATION 1. Disconnect the negative battery cable.
2. Remove the sound insulator on 1988- 89 vehicles or the console trim
plate on 1990-92 vehicles.
Fig. 1: Exploded view of the clutch swit ch mounting - on most models, the clutch
switch adjusts automatically
3. Unplug the clutch switch connector.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 362
OIL PRESSURE SENDING UNIT
Replace the sending unit by disconnecting
the electrical connector and using a
special socket to remove it.
ENGINE
MECHANICAL ENGINE
REMOVAL & INSTALLATION
In the process of removing the engine, you will come across a number of steps
which call for the removal of a separ ate component or system, such as
"disconnect the exhaust system " or "remove the radiator." In most instances, a
detailed removal procedure can be found elsewhere in this repair guide.
It is virtually impossible to list each individual wire and hose which must be
disconnected, simply because so many different model and engine
combinations have been manufactured. Careful observation and common
sense are the best possible approaches to any repair procedure.
Removal and installation of the engine ca n be made easier if you follow these
basic points:
• If you have to drain any of the fl uids, use a suitable container.
• Always tag any wires or hoses and, if possible, the components they
came from before disconnecting them.
• Because there are so many bolts and fasteners involved, store and label
the retainers from com ponents separately in muffin pans, jars or coffee
cans. This will prevent conf usion during installation.
• After unbolting the transmission or trans axle, always make sure it is
properly supported.
• If it is necessary to disconnect t he air conditioning system, have this
service performed by a qualified tec hnician using a recovery/recycling
station. If the system does not have to be disconnected, unbolt the
compressor and set it aside.
• When unbolting the engine mounts, a lways make sure the engine is
properly supported. When removing t he engine, make sure that any
lifting devices are properly attached to the engine. It is recommended
that if your engine is supplied with lifting hooks, your lifting apparatus be
attached to them.
• Lift the engine from its compartment sl owly, checking that no hoses,
wires or other component s are still connected.
• After the engine is clear of the compar tment, place it on an engine stand
or workbench.
• After the engine has been removed, y ou can perform a partial or full
teardown of the engine using the procedur es outlined in this repair guide.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 404
13. Replace the radiator assembly by
reversing the above steps. Check that
radiator lower cradles are locat ed properly in radiator recess.
14. Refill the cooling system. Check the engine oil and transmission fluid
levels, if necessary. Run engine for a short period of time and check for
leaks.
ENGINE OIL COOLER
The engine oil cooler consists of an adapter, bolted to the engine block, to
which the oil filter is scr ewed onto. The adapter has 2 hoses which attach to the
oil cooler and the radiator , these hoses are the inlet and return lines.
REMOVAL & INSTALLATION 1. Disconnect the negative battery cabl e. Drain the cooling system into a
suitable container.
CAUTION - When draining the coolant, keep in mind that cats and dogs are
attracted by the ethylene gl ycol antifreeze, and are quite likely to drink any that
is left in an uncovered container or in puddles on the ground. This will prove
fatal in sufficient quantity. Always drai n the coolant into a sealable container.
Coolant should be reused unless it is contaminated or several years old.
2. Remove the radiator, if the oil c ooler is to be repaired or replaced,
otherwise remove the engine oil cooler from the radiator as necessary.
3. Remove the oil filter.
4. Remove the hoses from the oil cooler adapter.
5. Unscrew the oil cooler adapter re tainer and remove the assembly.
Discard the gasket.
6. Installation is the reverse of t he removal procedure. Use new gaskets.
ELECTRIC COOLING FAN
REMOVAL & INSTALLATION 1. Disconnect the battery ground cable.
2. Remove the air cleaner and ducts, if necessary.
3. Unplug the fan harness connector.
4. Remove the fan frame to radiator support mounting bolts and remove the
fan assembly. Some models are retai ned by clips. Remove these, then
slide the fan assembly from the radiator.
5. Install the cooling fan frame to t he radiator support bolt. Reconnect the
wiring harness, the negative battery cable and check fan operation.
BELT-DRIVEN COOLING FAN
REMOVAL & INSTALLATION 1. Disconnect the negative battery cable.
2. Remove the fan shroud, as required.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 547
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
OPERATION
All models are equipped with
this system, which consists of a metering valve, a
vacuum line to the carburet or or intake manifold, and cast-in exhaust passages
in the intake manifold. The EGR valve is controlled by vacuum, which opens
and closes in response to the vacuum signals to admit exhaust gases into the
air/fuel mixture. The exhaust gases lower peak combustion temperatures,
reducing the formation of NOx. The valve is closed at idle and wide open
throttle, but is open between the two extreme positions.
There are actually four types of EGR systems: Ported, Positive Back-Pressure,
Negative Backpressure and Digital. The pr inciple of all the systems are the
same; the only difference is in the me thod used to control how the EGR valve
opens.
Too much EGR flow at idle, cruise or during cold operation may result in the
engine stalling after cold start, the engine stalling at idle after deceleration,
vehicle surge during cruise and rough idle . If the EGR valve is always open, the
vehicle may not idle. Too little or no EGR flow allows combustion temperatures
to rise, which could result in spar k knock (detonation), engine overheating
and/or emission test failure.
A Thermal Vacuum Switch (TVS) or vacuum control solenoid may sometimes\
be used in combination with the EGR va lve. The TVS will close off vacuum
during cold operation. A va cuum control solenoid uses Pulse Width Modulation
(PWM) to turn the solenoid ON and OFF numerous times a second and varies
the amount of ON time (pulse width) to vary the amount of ported vacuum
supplied the EGR valve.
PORTED VALVE
In the ported system, the amount of ex haust gas admitted into the intake
manifold depends on a ported vacuum signal. A ported vacuum signal is one
taken from the carburetor above the th rottle plates; thus, the vacuum signal
(amount of vacuum) is dependent on how far the throttle plates are opened.
When the throttle is closed (idle or dec eleration) there is no vacuum signal.
Thus, the EGR valve is closed, and no exhaust gas enters the intake mani\
fold.
As the throttle is opened, a vacuum is produced, which opens the EGR valve,
admitting exhaust gas into the intake manifold.
POSITIVE BACKPRE SSURE VALVE
This valve operates the same as the ported, except, it has an internal air bleed
that acts as a vacuum regulator. T he bleed valve controls the amount of
vacuum inside the vacuum chamber duri ng operation. When the valve receives
sufficient exhaust backpressure through the hollow shaft, it closes the bleed; at
this point the EGR valve opens.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 562
Air is injected into either the exhaust
port(s), the exhaust manifold(s) or the
catalytic converter by an engine driven ai r pump. The system is in operation at
all times and will bypass air only mom entarily during deceleration and at high
speeds. The bypass function is performed by the air control valve, while the
check valve protects the air pump by pr eventing any backflow of exhaust gases.
The AIR system helps r educe HC and CO content in the exhaust gases by
injecting air into the exhaust ports dur ing cold engine operation. This air
injection also helps the catalytic conv erter to reach the proper temperature
quicker during warmup. When the engine is warm (Closed Loop), the AIR
system injects air into the beds of a th ree-way converter to lower the HC and
the CO content in the exhaust.
The system utilizes the following components:
1. An engine driven AIR pump.
2. AIR Control valves (Air Control, Air Switching).
3. Air flow and control hoses.
4. Check valves.
5. A dual-bed, three-way catalytic converter.
6. A deceleration back-fire control valve - 2.8L engine only.
The belt driven, vane-type air pump is lo cated at the front of the engine and
supplies clean air to the AIR system fo r purposes already stated. When the
engine is cold, the Electronic Control Module (ECM) energizes an AIR control
solenoid. This allows air to flow to the AIR switching valve. The AIR switching
valve is then energized to direct air to the exhaust ports.
When the engine is warm, the ECM de-energ izes the AIR switching valve, thus
directing the air between the beds of the catalytic converter. This provides
additional oxygen for the ox idizing catalyst in the second bed to decrease HC
and CO, while at the same time keeping oxygen levels low in the first bed,
enabling the reducing catalyst to effect ively decrease the levels of NOx.
If the AIR control valve detects a r apid increase in manifold vacuum
(deceleration), certain operat ing modes (wide open throttle, etc.) or if the ECM
self-diagnostic system detects any problem in the system, air is diverted to the
air cleaner or directly into the atmosphere.
The primary purpose of the EC M's divert mode is to prevent backfiring. Throttle
closure at the beginning of deceleration will temporarily create air/fuel mixtures
which are too rich to burn completely . These mixtures become burnable when
they reach the exhaust if combined with the injection ai r. The next firing of the
engine will ignite this mixt ure causing an exhaust backf ire. Momentary diverting
of the injection air from the exhaust prevents this.
The AIR system check valves and hoses should be checked periodically for any
leaks, cracks or deterioration.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 577
MALFUNCTION INDICATOR LAMP
The primary function of the MIL is to adv
ise the operator and the technician that
a fault is detected, and, in most cases, a code is stored. Under normal
conditions, the malfunction indicator la mp will illuminate when the ignition is
turned ON. Once the engine is started and running, the ECM will perform a
system check and extinguish the lamp if no fault is found.
Additionally, the lamp can be used to retrieve stored codes after the system is
placed in the Diagnostic Mode. Codes ar e transmitted as a series of flashes
with short or long pauses. When the syst em is placed in the Field Service
Mode, the dash lamp will indicate open loop or closed loop function to the
technician.
INTERMITTENTS
If a fault occurs intermittently, such as a loose connector pin breaking contact
as the vehicle hits a bump, the ECM will note the fault as it occurs and energize
the dash warning lamp. If the problem se lf-corrects, as with the terminal pin
again making contact, the dash lamp will extinguish after 10 seconds but\
a code
will remain stored in the ECM memory.
When an unexpected code appe ars during diagnostics, it may have been set
during an intermittent failure that self-c orrected; the codes are still useful in
diagnosis and should not be discounted.
OXYGEN SENSOR
OPERATION
An oxygen sensor is used on all models. The sensor protrudes into the exhaust
stream and monitors the oxygen content of the exhaust gases. The difference
between the oxygen content of the exhaust gases and that of the outside air
generates a voltage si gnal to the ECM. The ECM monitors this voltage and,
depending upon the value of the signal rece ived, issues a command to adjust
for a rich or a lean condition.
No attempt should ever be made to meas ure the voltage output of the sensor.
The current drain of any conventional vo ltmeter would be such that it would
permanently damage the sensor.