fuel type CHEVROLET CAMARO 1982 Repair Guide

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.

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spark plug must fire 5° before each pist
on reaches TDC. This only holds true,
however, when the engine is at idle speed.
As the engine speed increases, the pist ons go faster. The spark plugs have to
ignite the fuel even sooner if it is to be completely ignited when the piston
reaches TDC.
If the ignition is set too far advanced (B TDC), the ignition and expansion of the
fuel in the cylinder will occu r too soon and try to force the piston down while it is
still traveling up. This causes engine ping. If the ignition spark is set too far
retarded, after TDC (ATDC), the pi ston will have already passed TDC and
started on its way down when the fuel is igni ted. This will cause the piston to be
forced down for only a portion of its trav el, resulting in poor engine performance
and lack of power.
When timing the engine, the Number 1 pl ug wire should be used to trigger the
timing light. On engines where timing is adjustable, the notch for the No. 1
cylinder is usually scribed across all th ree edges of the double sheaf pulley.
Another notch located 180° away from t he No. 1 cylinder notch is scribed only
across the center section of the pulley to make it distinguishable from the No. 1
cylinder notch.
There are two basic types of timing light s available. The first type of light
operates from the car's battery. Two al ligator clips connect to the battery
terminals, while a third wire connects to the spark plug with an adapter or to the
spark plug wire with an inductive pickup. This type of light is more expensive,
but the xenon bulb provides a nice bright flash which can even be seen in
sunlight. The second type replaces the battery source with 110-volt house
current. Some timing lights have other func tions built into them, such as dwell
meters, tachometers, or re mote starting switches. These are convenient, in that
they reduce the tangle of wires under t he hood, but may duplicate the functions
of tools you already have.
Because this car uses electronic ignition, you should use a timing light with an
inductive pickup. This pickup simply cl amps around the Number 1 spark plug
wire (in this case, the coil wire), elimin ating the adapter. It is not susceptible to
crossfiring or false triggering, which ma y occur with a conventional light due to
the greater voltages produc ed by these systems.
ADJUSTMENT
When adjusting the timing, refer to the instructions on the emission control
sticker inside the engine compartment. If th e instructions on the label disagree
with the procedure listed below, follo w the instructions on the label.
1982-87 VEHICLES 1. Locate the timing marks on the cran kshaft pulley and the front of the
engine.

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FUEL SYSTEM

BASIC FUEL SYSTEM DIAGNOSIS

When there is a problem star ting or driving a vehicle, two of the most important
checks involve the ignition and the fuel systems. The questions most mechanics
attempt to answer first, "is there spark?" an d "is there fuel?" will often lead to
solving most basic problems. For igni tion system diagnosis and testing, please
refer to the information on engine electr ical components and ignition systems
found earlier in this repair guide. If the ignition system checks out (there is
spark), then you must determine if the f uel system is operating properly (is there
fuel?).

CARBURETED FUEL SYSTEM

MECHANICAL FUEL PUMP
All fuel pumps used on carbureted V6 and V8 engines are of the diaphragm
type and are serviced by replacement onl y. No adjustments or repairs are
possible. The fuel pump is mounted on th e left front (V6) and right front (V8) of
the engine.
The fuel pumps are also equipped with vapor return lines for purposes of
emission control and to reduce vapor lock. All pumps are operated by an
eccentric on the camshaft. On V6 an d V8 engines, a pushrod between the
camshaft eccentric and the fuel pump operates the pump.
REMOVAL & INSTALLATION
When disconnecting the fuel pump outlet fitting, always use two wrenches to
avoid twisting the line.
1. Disconnect the fuel in take and outlet lines at the pump, then plug the
pump intake line.
2. Remove the two pump mounting bol ts and lockwashers; remove the
pump and its gasket.
3. If the pump pushrod is to be remo ved from the V8, remove the two
adapter bolts and lockwashers, then re move the adapter and its gasket.
4. Install the fuel pump with a new gasket reversing the removal procedure.
Coat the mating surfaces with sealer.
5. Connect the fuel lines and check for leaks.

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1. Disconnect the pressure gauge. R
un the fuel line into a graduated
container.
2. Run the engine at idle until one pint of gasoline has been pumped. One
pint should be delivered in 30 seconds or less. There is normally enough
fuel in the carburetor float bowl to perform this test, but refill it if
necessary.
3. If the delivery rate is below the mini mum, check the lines for restrictions
or leaks, then r eplace the pump.
CARBURETORS
The V6 engine is equipped with the Ro chester E2SE carburetor, V8 engines
use the E4ME and E4MC. These carburet ors are of the downdraft design and
are used in conjunction with the CCC system for fuel cont rol. They have special
design features for optimum air/fuel mixt ure control during all ranges of engine
operation.
An electric solenoid in the carburetor controls the air/fu el ratio. The solenoid is
connected to an Electronic Control Module (ECM) which is an on-board
computer. The ECM provides a controllin g signal to the solenoid. The solenoid
controls the metering rod(s) and an id le air bleed valve, thereby closely
controlling the air/fuel ratio throughout the operating range of the engine.
MODEL IDENTIFICATION
General Motors Rochester carburetors ar e identified by their model code. The
first number indicates the number of ba rrels, while one of the last letters
indicates the type of choke used. These are V for the manifold mounted choke
coil, C for the choke coil mounted in the carburetor body, and E for electric
choke, also mounted on the carburetor. Model codes ending in A indicate an
altitude-compensatin g carburetor.
Because of their intricate nature and co mputer controls, the E2SE, E4ME and
E4MC carburetors should only be se rviced by a qualified technician.
PRELIMINARY CHECKS
The following should be observed befor e attempting any adjustments.
1. Thoroughly warm the engine. If the engine is cold, be sure that it reaches
operating temperature.
2. Check the torque of all carburet or mounting nuts and assembly screws.
Also check the intake manifold-to-cyli nder head bolts. If air is leaking at
any of these points, any attempts at adjustment will inevitably lead to
frustration.
3. Check the manifold heat control valve (if used) to be sure that it is free.
4. Check and adjust the choke as necessary.
5. Adjust the idle speed and mixture. If the mixture screws are capped,
don't adjust them unless all other c auses of rough idle have been
eliminated. If any adjustments are per formed that might possibly change

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rapidly. Failure to replace all parts s
upplied with the kit (especially gaskets) can
result in poor performance later.
Some carburetor manufacturers supply overhaul kits for three basic types:
minor repair; major repair; and gasket kits. Certain parts may be expected in
most kits based on the desired degree of overhaul.
MINOR REPAIR KITS
• All gaskets
• Float needle valve
• All diaphragms
• Spring for the pump diaphragm
MAJOR REPAIR KITS
• All jets and gaskets
• All diaphragms
• Float needle valve
• Pump ball valve
• Float
• Complete intermediate rod
• Intermediate pump lever
• Some cover hold-down screws and washers
GASKET KITS
• All gaskets
Efficient carburetion depends greatly on careful cleaning and inspection during
overhaul, since dirt, gum, water, or varnis h in or on the carburetor parts are
often responsible for poor performance.
Overhaul your carburetor in a clean, dust-free area. Carefully disassemble the
carburetor, referring often to the explod ed views and directions packaged with
the rebuilding kit. Keep all similar and look-alike parts separated during
disassembly and cleaning to avoid accidental interchange during assembly\
.
Make a note of all jet sizes.
When the carburetor is disassembled, wash all parts (except diaphragms,
electric components, pump pl unger, and any other plastic, leather, fiber, or
rubber parts) in clean carbur etor solvent. Do not leave parts in the solvent any
longer than is necessary to sufficiently loosen the deposits. Excessive cleaning
may remove the special finish from the float bowl and choke valve bodies,
leaving these parts unfit for service. Rinse all parts in clean solvent and blow
them dry with compressed air or allow them to air dry. Wipe clean all cork,
plastic, leather, and fiber parts with a clean, lint-free cloth.
Blow out all passages and jets with comp ressed air and be sure that there are
no restrictions or blockages. Never use wi re or similar tools to clean jets, fuel

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THROTTLE BODY INJECTION SYSTEM

SYSTEM DESCRIPTION
The throttle body injection (TBI) system used on 2.5L (VIN 2) and 5.0L (VIN E)
engines is centrally located
on the intake manifold. Its function is to supply the
correct air/fuel mixture to the engine, as directed by the Engine Control Module
(ECM).
The TBI unit consists of two relatively simple casting assemblies: a throttle body
and a fuel metering assembly. Components include, a pressure regulator, idle
air control valve, fuel injector(s), thro ttle position sensor, fuel inlet and a fuel
return fitting.
The Throttle Body Injection identifi cation number is stamped on the lower
mounting flange located near the TPS. Th e number is in alphabetical code and
should be noted before servicing the unit.
An oxygen sensor in the exhaust syst em functions to provide feedback
information to the ECM as to oxygen content in the exhaust. The ECM then
uses this information to modify fuel de livery to achieve as near as possible an
ideal air/fuel ratio of 14.7 :1. This ratio permits the ca talytic converter to become
more effective in reducing emissions wh ile providing acceptable driveability.
Should you encounter any type of engine performance problem, have a
complete CCC system test performed by a qualified, professional technician. If
the fault lies in the injection system, you can use the following procedures to
remove the TBI unit and replace the defective component(s).
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 relieve fuel tank pressure and do not tighten
until service has been completed.
3. Fuel system pressure is automatic ally relieved when the engine is turned
OFF. No further action is necessary.
When disconnecting fuel lines, there ma y still be a small amount of fuel
released. Cover the fuel line connection wi th a shop cloth to collect the fuel,
then place the cloth in an approved container.
ELECTRIC FUEL PUMP
REMOVAL & INSTALLATION
The fuel pump is part of t he fuel sender assembly located inside the fuel tank.
1. Release the fuel syst em pressure and disconnec t the negative battery
cable.

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INJECTOR REPLACEMENT
Use care in removing injectors to prev
ent damage to the electrical connector
pins on top of the injector, the fuel injector fuel filter and nozzle. The fuel injector
is serviced as a complete assembly on ly and should never be immersed in any
type of cleaner.
SINGLE INJECTOR UNITS 1. Relieve the fuel system pressure.
2. Remove the air cleaner.
3. Detach the injector connector by squeezing the two tabs together and
pulling straight up.
4. Remove the screws securing the fuel meter cover. Note the location of
any short screws for correct placement during reassembly.
CAUTION - DO NOT remove the four screws se curing the pressure regulator to
the fuel meter cover. The fuel pressure regulator includes a large spring under
heavy tension which could cause personal injury if released.
5. With the old fuel meter gasket in place to prevent damage to the casting,
use a prytool and fulcrum to pry the inje ctor carefully until it is free from
the fuel meter body.
6. Remove the injector.
7. Remove the large O-ring and steel back-up washer at the top of the
injector cavity in the fuel meter body.
8. Remove the small O-ring located at the bottom of the injector cavity.
To Install: 9. Lubricate the new, small O-ring with automatic transmission fluid; then,
push the new O-ring on the nozzle end of the injector up against the
injector fuel filter.
10. Install the steel backup washer in the recess of the fuel meter body.
Lubricate the new large O-ring with automatic transmission fluid, then
install the O-ring directly above t he backup washer, pressing the O-ring
down into the cavity recess. The O-ri ng is properly installed when it is
flush with the casting surface.
WARNING - Do not attempt to reverse this procedure and install the backup
washer and O-ring after the injector is located in the cavity. To do so will
prevent proper seating of the O-ring in th e cavity recess which could result in a
fuel leak and possible fire.
11. Install the injector by using a pushing/twisting mo tion to center the nozzle
O-ring in the bottom of the injector cavity and aligning the raised lug on
the injector base with the notch cast into the fuel meter body. Push down
on the injector making sure it is fully seated in the cavity. Injector
installation is correct when the lug is seated in the notch and the
electrical terminals are parallel to the throttle shaft.

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Fig. 2: Fuel pressure regulator assembly
THROTTLE POSITION SENSOR (TPS)
REMOVAL & INSTALLATION 1. Remove the air cleaner.
2. Disconnect the electrical connector.
3. Remove the TPS attaching screws and lockwashers.
4. Remove the TPS.
To install: 5. Install the throttle position sensor. On 2.5L engines, make sure the TPS pickup lever is located above the tang on the throttle actuator lever. On
5.0L engines, line up the TPS lever with the TPS drive lever on the
throttle body.
6. Install the TPS attaching screws.
7. Adjust the TPS volt age, if applicable.
8. Reconnect the electrical connector.
9. Install the air cleaner.
IDLE AIR CONTROL (IAC) VALVE
REMOVAL & INSTALLATION 1. Unplug the electrical connector from idle air control valve.
2. Remove the idle air control valve.
To install: 3. Before installing the idle air contro l valve, measure the distance that the
valve is extended. Measurement s hould be made from the motor housing
to the end of the cone. It should not exceed 28.5mm (1
1/8 in.), or damage
to the valve may occur when installed.
4. Identify the replacement IAC valve as being either Type 1 (with collar at
electric terminal end) or Type 2 (without collar). If measuring distance is
greater than specified abov e, proceed as follows:
• Type 1: Use finger pressure to slowly retract the pintle.

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•

Type 2: Compress retaining spring from valve while turning valve
in with a clockwise motion. Return spring to original position with
straight portion of spring end aligned with flat surface of valve.
On IAC valves that have already been in service, do not push or pull on the
valve pintle. The force required to move the pintle may damage the threads on
the worm drive.
5. Use a new gasket or O-ring and install the IAC valve into the throttle body.
6. Allow the ECM to reset the idle air control valve using the procedure
described earlier in this section.

Fig. 1: Idle air control valve installation
CROSSFIRE INJECTION SYSTEM

SYSTEM DESCRIPTION
The Model 400 Electronic Fuel Injection (EFI) system is a computer controlled
system that uses a pair of Throttle Body Injection (TBI) units, which are
mounted on a single manifold cover on t he 5.0L (VIN 7) engine. Since each TBI
feeds the cylinders on the opposite side of the engine, the system has acquired
the name of Crossf ire Injection.
Fuel is supplied, by an electric fuel pum p located in the fuel tank, to the front
TBI fuel accumulator. From the accumulator, it is carried to the rear TBI fuel
pressure regulator by a c onnecting tube. Unused fuel is sent to the fuel tank
through a separate return line.

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Fig. 2: IAC valve installation
MULTI-PORT FUEL INJECTION SYSTEMS

SYSTEM DESCRIPTIONS
The Multi-Port Fuel Injection (MPFI or MFI) systems were first introduced on the
1985 models. They may be called different names (Port Fuel Injection-PFI,
Tuned Port Injection-TPI, Sequential Fuel Injection-SFI), however, all of the
systems are similar in operation.
The systems are controlled by an Elec tronic Control Module (ECM) which
monitors the engine operations and gen erates output signals to provide the
correct air/fuel mixture, ignition timing and idle speed. Input information to the
ECM is provided by the oxygen sens or, temperature sensors, detonation
sensor, mass air flow sensor and throttle position sensor. A system may use all
or some of these sensors, depending on the year and engine application. The
ECM also receives information concerning engine rpm, road speed,
transmission gear position, power steer ing and air conditioning status.
All of the systems use multiple injector s, aimed at the intake valve at each
intake port, rather than the centrally lo cated injector(s) found on the earlier
Throttle Body Injection (TBI) and Crossfir e Injection systems. The injectors are
mounted on a fuel rail and ar e activated by a signal from the electronic control
module. The injector is a solenoi d-operated valve which remains open
depending on the width of t he electronic pulses (length of the signal) from the
ECM; the longer the open time, the more f uel is injected. In this manner, the
air/fuel mixture can be precisely c ontrolled for maximum performance with
minimum emissions.
There are two different types of f uel management systems used on the multi-
port fuel injection engines. The mass air flow system and the speed density
system.