1982 CHEVROLET CAMARO check engine

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 560

Fig. 1: A common THERMAC air cleaner and components

Fig. 2: THERMAC vacuum motor modes of operation
SERVICE 1. Check the vacuum hoses for leaks, kinks, breaks, or improper connections and correct any defects.
2. With the engine off, check the pos ition of the damper door within the
snorkel. A mirror can be used to make this job easier. The damper door
should be open to admit outside air.

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) 563
On the 2.8L engine only, an anti-backfire (g
ulp) valve is used to allow air flow
into the intake manifold. This is us ed to help prevent backfire during high
vacuum deceleration conditions. The extra air enters the intake system to lean
the rich air/fuel mixture. The valve is o perated by the intake manifold vacuum to
allow air from the air filter to flow into the intake manifold.

Fig. 1: AIR system operation - cold engine

Fig. 2: AIR system operation - warm engine

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 564

Fig. 3: Anti-backfire valve used on 2.8L engines
TESTING
ANTI-BACKFIRE VALVE
1. Remove the air cleaner and plug t he air cleaner vacuum source. Connect
a tachometer to the engine.
2. With the engine idling, remove the vacuum signal hose from the intake
manifold.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 565
3. Reconnect the signal
hose and listen for air flow through the ventilation
tube into the anti-backfire valve. A speed drop should be noticed when
the hose is reconnected.
4. If these conditions are not found, check hoses for restrictions or leaks. If
hoses are OK, replace the anti-backfire valve.
AIR PUMP 1. Check the drive belt tension.
2. Increase the engine speed and observe an increase in air flow. If air flow
does not increase, replace the air pump.
CONTROL VALVE 1. Remove the hoses. Blow through t he valve (toward the cylinder head).
2. Then, suck through the valve (or blow through the other side). If air flows
in one direction, the valve is operative. If not, replace the control valve.
REMOVAL & INSTALLATION
AIR PUMP 1. Remove the AIR control valves and/or adapter at the pump.
2. Loosen the air pump adjustment bolt and remove the drive belt.
3. Unscrew the pump mounting bolts and then remove the pump pulley.
4. Unscrew the pump mounting bol ts and then remove the pump.
To install: 5. Position the pump into place and secure it with the mounting bolts.
6. Install the pump pulley.
7. Install the air pump drive belt and adjust pump belt with the pump
adjustment bolt.
8. Install the AIR contro l valves and/or adapter.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 569

Fig. 7: AIR system control valv e assembly; all models similar
EARLY FUEL EVAPORATION (EFE)
OPERATION
The EFE system is used on some of the engines to provide a source of rapid
engine heat up during cold operations. It hel ps reduce the time that carburetor
choking is required and helps reduce exhaust emissions.
There are two types of EF E systems. The vacuum servo type, consists of a
valve located in the exhaust manifold , an actuator and a Thermal Vacuum

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 570
Switch (TVS). The electrical type, cons
ists of a ceramic grid located under the
base of the carburetor.
A check of the operation should be made at regular maintenance intervals.
TESTING
VACUUM SERVO TYPE 1. With the engine cold, observe the posit ion of the actuator arm. Start the
engine. The arm should move toward the diaphragm (closing the valve).
2. If the arm does not move, remove the hose and check for vacuum. If still
no vacuum, remove the top hose from the TVS switch and check for
vacuum.
3. If vacuum is present in the top hose, replace the TVS switch.
4. If vacuum is present at the actuator and it does not move, try to free the
valve. If the valve cannot be freed, it must be replaced.
ELECTRICAL TYPE 1. Turn the ignition ON with the engine co ld and probe both terminals of the
heater switch connector with a test light.
• If 1 wire has power, replace the heater switch.
• If neither wire has power, repai r the ignition circuit.
• If both wires have power, probe the pink wire at the heater
connector (if no power, repair the c onnector of the heater switch).
2. If power exists at the pink wire , disconnect the heater connector and
connect a tester across the harness terminal. If no power, repair the
ground wire; if power exists, check the resistance of the heater.
3. If heater is over 3 ohm s, replace the heater. If under 3 ohms, replace the
connector, start the engine (operate to normal temperature) and probe
the pink wire. If no power, the system is OK; if power exists, replace the
heater switch.
REMOVAL & INSTALLATION
VACUUM SERVO TYPE 1. Disconnect the vacuum hose at the EFE.
2. Remove exhaust pipe to manifold nuts.
3. Remove the crossover pipe. Complete removal is not always necessary.
4. Remove the EFE valve.
To install: 5. Position the EFE valve into place.
6. Install the crossover pipe.
7. Install the exhaust pi pe to manifold nuts.
8. Connect the vacuum hose at the EFE.

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.