1982 CHEVROLET CAMARO coolant temperature

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 142
When current flows through
a load, the voltage beyond the load drops. This
voltage drop is due to the resistance created by the load and also by small
resistances created by corrosion at the connectors and damaged insulation on
the wires. The maximum allo wable voltage drop under load is critical, especially
if there is more than one load in t he circuit, since all voltage drops are
cumulative.
1. Set the voltmeter selector s witch to the 20 volt position.
2. Connect the multimeter negative lead to a good ground.
3. Operate the circuit a nd check the voltage prior to the first component
(load).
4. There should be little or no voltage drop in the circuit prior to the fi\
rst component. If a voltage drop exists, the wire or connectors in the circuit
are suspect.
5. While operating the first component in the circuit, probe the ground side
of the component with the positive meter lead and observe the voltage
readings. A small voltage drop should be noticed. This voltage drop is
caused by the resistance of the component.
6. Repeat the test for each component (load) down the circuit.
7. If a large voltage drop is noticed, the preceding component, wire or
connector is suspect.
RESISTANCE

Fig. 3: Checking the resistance of a coolant temperature sensor with an
ohmmeter. Reading is 1.04 kilohms

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 467
8. According to the tool manufacture
r's instructions, connect a remote
starting switch to the starting circuit.
9. With the ignition switch in the OFF position, use the remote starting
switch to crank the engine through at least five compression strokes
(approximately 5 seconds of cranking) and record the highest reading on
the gauge.
10. Repeat the test on each cylinder, cranking the engine approximately the
same number of compression stroke s and/or time as the first.
11. Compare the highest readi ngs from each cylinder to that of the others.
The indicated compression pre ssures are considered within
specifications if the lo west reading cylinder is within 75 percent of the
pressure recorded for the highest readi ng cylinder. For example, if your
highest reading cylinder pressure was 150 psi (1034 kPa), then 75
percent of that would be 113 psi (779 kPa). So the lowest reading
cylinder should be no less than 113 psi (779 kPa).
12. If a cylinder exhibits an unusually low compression reading, pour a
tablespoon of clean engine oil into the cylinder through the spark plug
hole and repeat the compression tes t. If the compression rises after
adding oil, it means that the cylinder's piston rings and/or cylinder bore
are damaged or worn. If the pressure re mains low, the valves may not be
seating properly (a valve job is needed), or the head gasket may be
blown near that cylinder. If compressi on in any two adjacent cylinders is
low, and if the addition of oil doesn' t help raise compression, there is
leakage past the head gasket. Oil and coolant in the combustion
chamber, combined with blue or const ant white smoke from the tail pipe,
are symptoms of this pr oblem. However, don't be alarmed by the normal
white smoke emitted from the tail pipe during engine warm-up or from
cold weather driving. There may be evidence of water droplets on the
engine dipstick and/or oil droplets in the cooling system if a head gasket
is blown.
OIL PRESSURE TEST
Check for proper oil pressu re at the sending unit passage with an externally
mounted mechanical oil pressure gauge (a s opposed to relying on a factory
installed dash-mounted gauge). A tachom eter may also be needed, as some
specifications may require running the engine at a specific rpm.
1. With the engine cold, locate and remo ve the oil pressure sending unit.
2. Following the manufacturer's inst ructions, connect a mechanical oil
pressure gauge and, if necessary, a tachometer to the engine.
3. Start the engine and allow it to idle.
4. Check the oil pressure reading when cold and record the number. You
may need to run the engine at a specified rpm, so check the
specifications chart located earlier in this section.
5. Run the engine until normal operati ng temperature is reached (upper
radiator hose will feel warm).
6. Check the oil pressure reading agai n with the engine hot and record the
number. Turn the engine OFF.

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) 549

Fig. 2: Negative backpressure EGR valve
DIGITAL EGR VALVE
The digital EGR valve, used on 3.1L (VIN T) engines, is designed to control the
flow of EGR independent of intake mani fold vacuum. The valve controls EGR
flow through 3 solenoid- opened orifices, which increa se in size, to produce 7
possible combinations. When a solenoid is energized, the armature with
attached shaft and swivel pintle, is lifted, opening the orifice.
The digital EGR valve is opened by t he ECM "quad-driver" (QDR), grounding
each solenoid circuit individually. The fl ow of EGR is regulated by the ECM
which uses information from the Coolant Temperature Sensor (CTS), Throttle
Position Sensor (TPS) and the Manifold Absolute Pressure (MAP) sensor to
determine the appropriate rate of flow for a particular engine operating
condition.

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) 580
4. Spray a commercial solvent onto the sensor threads and allow it to soak
in for at least five minutes.
5. Carefully remove the sensor wit h a special oxygen sensor socket.
To install: 6. First coat the new sensor's th reads with GM anti-seize compound No.
5613695 or the equivalent. This is not a conventional anti-seize paste.
The use of a regular compound may el ectrically insulate the sensor,
rendering it inoperative. Y ou must coat the threads with an electrically
conductive anti-seize compound. Installati on torque is 30 ft. lbs. (41 Nm).
Do not overtighten.
7. Reconnect the electric al wiring. Be careful not to damage the electrical
pigtail. Check the sensor boot fo r proper fit and installation.
8. Reconnect the negative battery cable.
COOLANT TEMPERATURE SENSOR
OPERATION
Most engine functions are affected by the coolant temperature. Determining
whether the engine is hot or cold is largely dependent on the temperature of the
coolant. An accurate temperature signal to the ECM is supplied by the coolant
temperature sensor. The coolant temperatur e sensor is a thermistor mounted in
the engine coolant stream. A thermistor is an electrical device that varies its
resistance in relation to changes in temperature. Low coolant temperature
produces a high resistance and high coolant temperature produces low
resistance. The ECM supplies a signal of 5 volts to the coolant temperature
sensor through a resistor in the ECM and measures the voltage. The voltage
will be high when the engine is cold and low when the engine is hot.
REMOVAL & INSTALLATION
1. Disconnect the negative battery cable.
2. Drain the cooling system to an appropr iate and clean container for reuse.
3. Disconnect the electrical wiring fr om the coolant temperature sensor.
4. Remove the coolant temperature sensor.
To install: 5. Install the coolant temperature sensor.
6. Connect the electrical wiring.
7. Fill the cooling system.
8. Connect the negative battery cable.
9. Start the engine and check for leaks.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 581

Fig. 1: Coolant temperature sensor. The in take air temperature sensor is similar
in appearance
IDLE AIR CONTROL (IAC) VALVE
OPERATION
Engine idle speeds are controlled by the ECM through the IAC valve mounted
on the throttle body. The ECM sends volt age pulses to the IAC motor windings
causing the IAC motor shaft and pintle to move IN or OUT a given distance
(number of steps) for each pulse (called counts). The movement of the pintle
controls the airflow around the throttle plat e, which in turn, controls engine idle
speed. IAC valve pintle position counts ca n be observed using a scan tool. Zero
counts correspond to a fully closed passage, while 140 counts or more
corresponds to full flow.
Idle speed can be categorized in 2 ways : actual (controlled) idle speed and
minimum idle speed. Contro lled idle speed is obtained by the ECM positioning
the IAC valve pintle. Resulting idle speed is determined by total air fl\
ow
(IAC/passage + PCV + throttle valve + ca librated vacuum leaks). Controlled idle
speed is specified at normal operating c onditions, which consists of engine
coolant at normal operating temper ature, air conditioning compressor OFF,
manual transmission in neutral or automatic transmission in D.
Minimum idle air speed is set at t he factory with a stop screw. This setting
allows a certain amount of air to bypas s the throttle valves regardless of IAC
valve pintle positioning. A co mbination of this air flow and IAC pintle positioning
allows the ECM to control engine idle speed. During normal engine idle
operation, the IAC valve pintle is positioned a calibrated number of steps
(counts) from the seat. No adjustment is required during routine maintenance.
Tampering with the minimum idle speed adjustment may result in premature
failure of the IAC valve or imprope rly controlled engine idle operation.

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.