
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 49
Upon release of the brake pedal, a spri
ng located inside the master cylinder
immediately returns the master cylinder pistons to the normal position. The
pistons contain check valv es and the master cylinder has compensating ports
drilled in it. These are uncovered as the pistons reach their normal position. The
piston check valves allow fluid to flow to ward the wheel cylinders or calipers as
the pistons withdraw. Then, as the return springs force the brake pads or shoes
into the released position, the excess fluid reservoir through the compensating
ports. It is during the time the pedal is in the released position that any fluid that
has leaked out of the syst em will be replaced through the compensating ports.
Dual circuit master cylinders employ tw o pistons, located one behind the other,
in the same cylinder. The primary pist on is actuated directly by mechanical
linkage from the brake peda l through the power booster. The secondary piston
is actuated by fluid tra pped between the two pistons. If a leak develops in front
of the secondary piston, it moves forward until it bottoms against the front of the
master cylinder, and the fluid trapped betw een the pistons will operate the rear
brakes. If the rear brakes develop a l eak, the primary piston will move forward
until direct contact with the secondary pi ston takes place, and it will force the
secondary piston to actuate the front brakes. In either case, the brake pedal
moves farther when the brakes are applied, and less braking power is available.
All dual circuit systems use a switch to wa rn the driver when only half of the
brake system is operational. This switch is usually located in a valve body which
is mounted on the firewall or the frame below the master cylinder. A hydraulic
piston receives pressure from both circui ts, each circuit's pressure being applied
to one end of the piston. When the pressures are in balance, the piston remains
stationary. When one circuit has a leak, however, the greater pressure in that
circuit during application of the brakes will push the piston to one side, closing
the switch and activating the brake warning light.
In disc brake systems, this valve body also contains a metering valve and, in
some cases, a proportioning valve. The metering valve keeps pressure fro\
m
traveling to the disc brakes on the front wheels until the brake shoes on the rear
wheels have contacted the drums, ensuri ng that the front brakes will never be
used alone. The proportioning va lve controls the pressure to the rear brakes to
lessen the chance of rear wheel lo ck-up during very hard braking.
Warning lights may be tested by depressi ng the brake pedal and holding it while
opening one of the wheel cyli nder bleeder screws. If this does not cause the
light to go on, substitute a new lamp , make continuity checks, and, finally,
replace the switch as necessary.
The hydraulic system may be checked for leaks by applying pressure to the
pedal gradually and steadily. If the pedal sinks very slowly to the floor, the
system has a leak. This is not to be conf used with a springy or spongy feel due
to the compression of air within the lin es. If the system leaks, there will be a
gradual change in the position of the pedal with a constant pressure.
Check for leaks along all lines and at wheel cylinders. If no external leaks are
apparent, the problem is inside the master cylinder.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 468
7. Compare your hot oil pressure reading
to that given in the chart. If the
reading is low, check the cold pressu re reading against the chart. If the
cold pressure is well above the spec ification, and the hot reading was
lower than the specificat ion, you may have the wr ong viscosity oil in the
engine. Change the oil, making sure to use the proper grade and
quantity, then repeat the test.
Low oil pressure readings could be attributed to internal component wear, pump
related problems, a low oil leve l, or oil viscosity that is too low. High oil pressure
readings could be caused by an overfilled crankcase, too high of an oil viscosity
or a faulty pressure relief valve.
BUY OR REBUILD?
Now that you have determined that your engine is worn out, you must make
some decisions. The question of whether or not an engine is worth rebuilding is
largely a subjective matter and one of per sonal worth. Is the engine a popular
one, or is it an obsolete model? Are parts available? Will it get acceptable gas
mileage once it is rebuilt? Is the car it's being put into worth keeping? Would it
be less expensive to buy a new engine, have your engine rebuilt by a pro,
rebuild it yourself or buy a used engine from a salvage yard? Or would it be
simpler and less expensive to buy another car? If you have considered all these
matters and more, and have still decided to r ebuild the engine, then it is time to
decide how you will rebuild it.
The editors of this information feel that most engine machining should be
performed by a professional machine shop. Don't think of it as wasting money,
rather, as an assurance that the job has been done right the first time. There
are many expensive and spec ialized tools required to perform such tasks as
boring and honing an engine block or having a valve job done on a cylinder
head. Even inspecting the parts requires expensive micrometers and gauges to
properly measure wear and clearances. Al so, a machine shop can deliver to
you clean, and ready to assemble parts, saving you time and aggravation. Your
maximum savings will come from perf orming the removal, disassembly,
assembly and installation of the engine and purchasing or renting only the tools
required to perform the above tasks. Depending on the particular
circumstances, you may save 40 to 60 perc ent of the cost doing these yourself.
A complete rebuild or overhaul of an engine involves replacing all of the moving
parts (pistons, rods, crankshaft, camsha ft, etc.) with new ones and machining
the non-moving wearing surfaces of t he block and heads. Unfortunately, this
may not be cost effective. For instanc e, your crankshaft may have been
damaged or worn, but it can be machined undersize for a minimal fee.
So, as you can see, you can replace ev erything inside the engine, but, it is
wiser to replace only those parts whic h are really needed, and, if possible,
repair the more expensive ones. Later in this section, we will break the engine
down into its two main components: t he cylinder head and the engine block. We
will discuss each component, and the re commended parts to replace during a
rebuild on each.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 573
7. Install the retaining bracket.
8. Connect the negative battery cable.
ELECTRONIC ENGINE CONTROLS
COMPUTER COMMAND CO NTROL (CCC) SYSTEM
The Computer Command Control (CCC) Sy stem is an electronically controlled
exhaust emission system that can m onitor and control a large number of
interrelated emission cont rol systems. It can monitor various engine/vehicle
operating conditions and then use this in formation to control multiple engine
related systems. The CCC syst em is thereby making constant adjustments to
maintain optimum vehicle performance und er all normal driving conditions while
at the same time allowing the catalyti c converter to effectively control the
emissions of HC, CO and NO
x.
OPERATION
The Electronic Control Module (ECM) is required to maintain the exhaust
emissions at acceptable le vels. The module is a sma ll, solid state computer
which receives signals from many source s and sensors; it uses these data to
make judgements about operating conditions and then control output signals to
the fuel and emission systems to ma tch the current requirements.
Inputs are received from m any sources to form a complete picture of engine
operating conditions. Some inputs are simp ly Yes or No messages, such as that
from the Park/Neutral switch; the vehicle is either in gear or in Park/Neutral;
there are no other choices. Other data is sent in quantitative input, such as
engine rpm or coolant temperature. T he ECM is pre-programmed to recognize
acceptable ranges or combinations of si gnals and control the outputs to control
emissions while providing good driv eability and economy. The ECM also
monitors some output circuits, making sure that the components function as
commanded. For proper engine oper ation, it is essential that all input and output
components function properly and comm unicate properly with the ECM.
Since the control module is programmed to recognize the presence and value
of electrical inputs, it will also note the lack of a signal or a radical change in
values. It will, for example, react to the loss of signal from the vehicle speed
sensor or note that engine coolant temperature has risen beyond acceptable
(programmed) limits. Once a fault is recognized, a numeric code is assigned
and held in memory. The SERVICE ENGIN E SOON Malfunction Indicator Lamp
(MIL), will illuminate to advise the operator that the system has detected a fault.
More than one code may be stored. Although not every engine uses every
code, possible codes range from 12-999. Additionally, the same code may carry
different meanings relative to each engine or engine family. For example, on the
3.3L (VIN N) engine, code 46 indicates a fault found in the power steering
pressure switch circuit. The same code on the 5.7L (VIN F) engine indicates a
fault in the VATS anti-theft system.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 576
The temporary nature
of the integrator's control is expanded by the block learn
function. The name is derived from the fact that the entire engine operating
range (load vs. rpm) is divided into sect ions or blocks. Within each memory
block is stored the correct fuel delivery value for that combination of load and
engine speed. Once the operating range enters a certain block, that stored
value controls the fuel delivery unless th e integrator steps in to change it. If
changes are made by the integrator, t he new value is memorized and stored
within the block. As the block learn makes the correction, the integrator
correction will be reduced until the integrator returns to 128; the block learn then
controls the fuel delivery with the new value.
Fig. 4: Inexpensive scan tools, such as this Auto Xray®, are available to
interface with your General Motors vehicle
The next time the engine operates within the block's range, the new value will
be used. The block learn data can also be read by a scan tool; the range is the
same as the integrator and should also center on 128. In this way, the systems
can compensate for engine wear, small air or vacuum leaks or reduced
combustion.
Any time the battery is disconnected, the block learn values are lost and must
be relearned by the ECM. This loss of corrected values may be noticed as a
significant change in driveab ility. To re-teach the system, make certain the
engine is fully warmed up. Drive the v ehicle at part throttle using moderate
acceleration and idle until normal performance is felt.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 628
SPARK PLUG HEAT RANGE
Spark plug heat range is
the ability of the plug to dissipate heat. The longer the
insulator (or the farther it extends in to the engine), the hotter the plug will
operate; the shorter the insulator (the cl oser the electrode is to the block's
cooling passages) the cooler it will operate. A plug that absorbs little heat and
remains too cool will quickly accumulate deposits of oil and carbon since it is
not hot enough to burn them off. This leads to plug fouling and consequently to
misfiring. A plug that absorbs too much heat will have no deposits but, due to
the excessive heat, the electrodes will burn away quickly and might possibly
lead to preignition or other ignition probl ems. Preignition takes place when plug
tips get so hot that they gl ow sufficiently to ignite the air/fuel mixture before the
actual spark occurs. This early igniti on will usually cause a pinging during low
speeds and heavy loads.
Fig. 3: Spark plug heat range
The general rule of thumb for choosing the correct heat range when picking a
spark plug is: if most of your driving is long distanc e, high speed travel, use a
colder plug; if most of your driving is stop and go, use a hotter plug. Original
equipment plugs are general ly a good compromise between the 2 styles and
most people never have the need to change their plugs from the factory-
recommended heat range.
REMOVAL & INSTALLATION
A set of spark plugs usually requi res replacement after about 20,000-30,000
miles (32,000-48,000 km), depending on y our style of driving. In normal
operation plug gap increases about 0.001 in. (0.025mm) for every 2500 miles
(4000 km). As the gap increases, the plug' s voltage requirement also increases.
It requires a greater voltage to jump t he wider gap and about two to three times

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 635
FIRING ORDERS
To avoid confusion, remove and tag th
e spark plug wires one at a time, for
replacement.
If a distributor is not keyed for installati on with only one orientation, it could have
been removed previously and rewired. Th e resultant wiring would hold the
correct firing order, but could change the relative placement of the plug towers
in relation to the engine. Fo r this reason it is imperative that you label all wires
before disconnecting any of them. Also, before removal, compare the current
wiring with the accompanying i llustrations. If the current wiring does not match,
make notes, to reflect how your engine is wired.
Fig. 1: 2.5L Engine - Engine firing or der: 1-3-4-2- Distributor Rotation:
Clockwise

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 638
ELECTRONIC IGNITION SYSTEM
GENERAL INFORMATION
The High Energy Ignition (HEI) system
controls the fuel combustion by
providing a spark to ignite the compress ed air/fuel mixture at the correct time.
To provide improved engine performance, fuel economy, and control of exhaust
emissions, the engine contro l module (ECM) controls distributor spark advance
(timing) with an ignition control system.
The distributor may have an internal, or ex ternal ignition coil. To be certain of
the type coil used for your vehicle, vis ually inspect the ignition system. If the
ignition coil is inside the distributor c ap, it connects through a resistance brush
to the rotor. If your vehicle is equipped with an external ignition coil, it connects
to the rotor through a high tension wire.
Fig. 1: Distributor with exterior ignition coil - 1987 vehicle shown
The distributor contains the ignition c ontrol module, and the magnetic triggering
device. The magnetic pickup assembly contains a permanent magnet, a pole
piece with internal "teeth", and a pickup co il (not to be confused with the ignition
coil).
All spark timing changes are done electr onically by the engine control module
(ECM) which monitors information from various engine sensors. The ECM
computes the desired spark timing and t hen signals the distributor ignition
module to change the timing accordingly. No vacuum or mechanical advance
systems are used.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 762
Loctite). If you're worried about getting so
mething together tight enough to hold,
but loose enough to avoid mechanical damage during assembly, one of these
products might offer substantial insurance. Before choosing a threadlocking
compound, read the label on the pa ckage and make sure the product is
compatible with the materials, fluids, etc. involved.
3. Crossthreading. This occu rs when a part such as a bolt is screwed into a
nut or casting at the wrong angle and forced. Cr ossthreading is more
likely to occur if access is diffic ult. It helps to clean and lubricate
fasteners, then to start threading the bolt, spark pl ug, etc. with your
fingers. If you encounter resistance, unscrew the part and start over
again at a different angle until it can be inserted and turned several t\
imes
without much effort. Keep in mind t hat many parts have tapered threads,
so that gentle turning will automatica lly bring the part you're threading to
the proper angle. Don't put a wrench on the part until it's been tightened
a couple of turns by hand. If you s uddenly encounter resistance, and the
part has not seated fully, don't force it. Pull it back out to make sure it's
clean and threading properly.
Be sure to take your time and be pati ent, and always plan ahead. Allow yourself
ample time to perform r epairs and maintenance.
TOOLS AND EQUIPMENT
Without the proper tools and equipment it is impossible to properly service your
vehicle. It would be virtually impossible to catalog every tool that you would
need to perform all of the oper ations in this repair guide. It would be unwise for
the amateur to rush out and buy an expens ive set of tools on the theory that
he/she may need one or more of them at some time.
The best approach is to proceed slowly, gathering a good quality set of those
tools that are used most frequently. Don't be misled by the low cost of bargain
tools. It is far better to spend a little more for better quality. Forged wrenches, 6
or 12-point sockets and fine tooth ratc hets are by far preferable to their less
expensive counterparts. As any good me chanic can tell you, there are few
worse experiences than trying to work on a vehicle with bad tools. Your
monetary savings will be far outweighed by frustration and mangled knuckles.
Begin accumulating those tools that are used most frequently: those associated
with routine maintenance and tune-up. In addition to the normal assortment of
screwdrivers and pliers, you should have the following tools:
• Wrenches/sockets and combination o pen end/box end wrenches in sizes 1/83/4 in. and/or 3mm-19mm 13/16 in. or 5/8 in. spark plug socket
(depending on plug type).
If possible, buy various length socket drive extensions. Universal-joint\
and
wobble extensions can be extremely usef ul, but be careful when using them, as
they can change the amount of torque applied to the socket.