GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 129
THE BATTERY
In most modern vehicles, the battery is
a lead/acid electrochemical device
consisting of six 2 volt subs ections (cells) connected in se ries, so that the unit is
capable of producing approximately 12 volt s of electrical pressure. Each
subsection consists of a series of positive and negative plates held a short
distance apart in a solution of sulfuric acid and water.
The two types of plates are of dissim ilar metals. This sets up a chemical
reaction, and it is this r eaction which produces current flow from the battery
when its positive and negative terminals are connected to an electrical \
load .
The power removed from the battery is r eplaced by the alternator, restoring the
battery to its original chemical state.
THE ALTERNATOR
On some vehicles there isn't an alter nator, but a generator. The difference is
that an alternator supplies alternating current which is then changed to direct
current for use on the vehicle, while a generator produces direct current.
Alternators tend to be more efficient and that is why they are used.
Alternators and generators are devices t hat consist of coils of wires wound
together making big electrom agnets. One group of coils spins within another set
and the interaction of the magnetic fields causes a current to flow. This current
is then drawn off the coils and fed into the vehicles electrical system.
GROUND
Two types of grounds are used in automot ive electric circuits. Direct ground
components are grounded to the frame thr ough their mounting points. All other
components use some sort of ground wire which is attached to the frame or
chassis of the vehicle. The electrical current runs through the chassis of the
vehicle and returns to the battery thr ough the ground (—) cable; if you look,
you'll see that the battery ground cabl e connects between the battery and the
frame or chassis of the vehicle.
It should be noted that a good percentage of electrical problems can be traced
to bad grounds.
PROTECTIVE DEVICES
It is possible for large surges of current to pass through the electrical system of
your vehicle. If this surge of current we re to reach the load in the circuit, the
surge could burn it out or severely dam age it. It can also overload the wiring,
causing the harness to get hot and melt t he insulation. To prevent this, fuses,
circuit breakers and/or fusible links are connected into the supply wires of the
electrical system. These items are nothing more than a built-in weak spot in the
system. When an abnormal amount of curr ent flows through the system, these
protective devices work as fo llows to protect the circuit:
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 148
ARMING SENSOR
The arming sensor is a protective switch
located in the power feed side of the
deployment loop. It is calibrated to clos e at low level velocity changes (lower
than the discriminating sens ors). This assures that the inflator module is
connected directly to the 36 volt output of the DERM or battery voltage feed
when either of the discrim inating sensors close.
DISCRIMINATING SENSORS
The discriminating sensors are wired in parallel on the ground side of the
deployment loop. These sensors are calib rated to close with velocity changes
which are severe enough to warrant deployment.
SIR COIL ASSEMBLY
The SIR coil assembly consists of two cu rrent carrying coils. They are attached
to the steering column and allow rotation of the steering wheel while maintaining
continuous contact of the deployment loop to the inflator module.
INFLATOR MODULES
Each inflator module consists of an inflat able bag and an inflator (a canister of
gas generating material with an initiati ng device). When the vehicle is in a
frontal crash of sufficient force, current flows through the deployment loops.
Current flowing through the initiator ignite s the material in the inflator module.
The gas produced from this reaction rapidly inflates the air bag.
Fig. 2: Forward discriminating se nsor location on 1990-1992 models
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 465
Fig. 12: Muffler hanger attachment
ENGINE RECONDITIONING DETE RMINING ENGINE CONDITION
Anything that generates heat and/or friction will eventually burn or wear out (i.e.
a light bulb generates heat, therefore its life span is limited). With this in mind, a
running engine generates trem endous amounts of both; friction is encountered
by the moving and rotating parts inside the engine and heat is created b\
y
friction and combustion of the fuel. Ho wever, the engine has systems designed
to help reduce the effects of heat and fr iction and provide added longevity. The
oiling system reduces the amount of fr iction encountered by the moving parts
inside the engine, while the cooling system reduces heat created by friction and
combustion. If either system is not main tained, a break-down will be inevitable.
Therefore, you can see how regular main tenance can affect the service life of
your vehicle. If you do not drain, flush and refill your cooling system at the
proper intervals, deposits will begin to accumulate in the radiator, thereby
reducing the amount of heat it can extrac t from the coolant. The same applies to
your oil and filter; if it is not changed often enoug h it becomes laden with
contaminates and is unable to properly lubricate the engine. This increases
friction and wear.
There are a number of methods for evaluat ing the condition of your engine. A
compression test can reveal the condition of your pistons, piston rings, cylinder
bores, head gasket(s), valves and valve seat s. An oil pressure test can warn
you of possible engine bearing, or oil pump failures. Excessive oil consumption,
evidence of oil in the engine air intake area and/or bluish smoke from the tail
pipe may indicate worn piston rings, worn valve guides and/or valve seals. As a
general rule, an engine that uses no more than one quart of oil every 1000
miles is in good condi tion. Engines that use one quart of oil or more in less than
1000 miles should first be checked for oil leaks. If any oil leaks are present,
have them fixed before dete rmining how much oil is consumed by the engine,
especially if blue smoke is not visible at the tail pipe.
COMPRESSION TEST
A noticeable lack of engine power, excessive oil consumption and/or poor fuel
mileage measured over an extended period are all indicators of internal engine
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) 513
1. Connect the vehicle battery.
2. Start the engine. Keep y
our eye on your oil pressure indicator; if it does
not indicate oil pressure within 10 se conds of starting, turn the vehicle
off.
WARNING - Damage to the engine can result if it is allowed to run with no oil
pressure. Check the engine oil level to make sure that it is full. Check for any
leaks and if found, repair the leaks be fore continuing. If there is still no
indication of oil pressure, y ou may need to prime the system.
3. Confirm that there are no fluid leaks (oil or other).
4. Allow the engine to reach nor mal operating temperature (the upper
radiator hose will be hot to the touch).
5. If necessary, set the ignition timing.
6. Install any remaining components such as the air cleaner (if removed for
ignition timing) or body panels which were removed.
BREAKING IT IN
Make the first miles on the new engine , easy ones. Vary the speed but do not
accelerate hard. Most importantly, do not lug the engine, and avoid sustained
high speeds until at least 100 miles. Ch eck the engine oil and coolant levels
frequently. Expect the engine to use a littl e oil until the rings seat. Change the
oil and filter at 500 miles, 1500 mile s, then every 3000 miles past that.
KEEP IT MAINTAINED
Now that you have just gone through all of that hard work, keep yourself from
doing it all over again by thoroughly maintaining it. Not that you may not have
maintained it before, heck you c ould have had one to two hundred thousand
miles on it before doing this. However, you may have bought the vehicle used,
and the previous owner did not keep up on maintenance. Which is why you just
went through all of that hard work. See?
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 626
ENGINE PERFORMANCE AND TUNE-UP
TUNE-UP PROCEDURES
In order to extract the full measure of performance and economy from your
engine it is essential that it is properly tuned at regul ar intervals. A regular tune-
up will keep your Camaro's engine running smoothly and will prevent the
annoying breakdowns and poor perform ance associated with an untuned
engine.
A complete tune-up should be performed every 30,000 miles (48,000 km). This
interval should be halved if the car is operated under severe conditions such as
trailer towing, prolonged idling, start-and- stop driving, or if starting or running
problems are noticed. It is assumed that the routine maintenance described in
General Information & Maintenance has been kept up, as this will have a
decided effect on the result s of a tune-up. All of the applicable steps of a tune-
up should be followed in order, as the result is a cumulative one.
If the specifications on the underhoo d tune-up sticker in the engine
compartment of your car disagree with th e "Tune-Up Specifications" chart in this
Section, the figures on the sticker must be used. The sticker often reflects
changes made during t he production run.
SPARK PLUGS
A typical spark plug consists of a metal shell surrounding a ceramic insulator. A
metal electrode extends downward through the center of the insulator and
protrudes a small distance. Located at the end of the plug and attached to the
side of the outer metal shell is the side el ectrode. The side electrode bends in at
a 90 angle so that its tip is just pas t and parallel to the tip of the center
electrode. The distance between these two electrodes (measured in
thousandths of an inch or hundredths of a millimeter) is called the spark plug
gap.
The spark plug does not pr oduce a spark, but instead provides a gap across
which the current can arc. The coil produces anywhere from 20,000 to 50,000
volts (depending on the type and application) which travels through the wires to
the spark plugs. The current passes along the center electrode and jumps the
gap to the side electrode, and in doing so, ignites the air/fuel mixture in the
combustion chamber.
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) 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.