ECO mode CHEVROLET CAMARO 1982 Repair Guide

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 596
recommended to have a qualified technici
an perform any further testing, if
needed.
FIELD SERVICE MODE
On fuel injected models, if the ALDL terminal B is grounded to terminal A with
the engine running, the system enters the Field Service Mode. In this mode, the
MIL will indicate whether the system is operating in open loop or closed loop.
If working in open loop, t he MIL will flash rapidly 2
1/2 times per second. In
closed loop, the flash rate slows to once per second. Additionally, if the system
is running lean in closed loop, the lamp will be off most of the cycle. A rich
condition in closed loop will cause the lamp to remain lit for most of the one
second cycle.
When operating in the Field Service M ode, additional codes cannot be stored
by the ECM. The closed loop timer is bypassed in this mode.
CLEARING CODES
Stored fault codes may be erased from me mory at any time by removing power
from the ECM for at least 30 seconds. It may be necessary to clear stored
codes during diagnosis to check for any re currence during a test drive, but the
stored should be written dow n when retrieved. The codes may still be required
for subsequent troubleshooting. Whenever a repair is complete, the stored
codes must be erased and the vehicle te st driven to confirm correct operation
and repair.
The ignition switch must be OFF any ti me power is disconnected or restored to
the ECM. Severe damage may result if this precaution is not observed.
Depending on the electric di stribution of the particular vehicle, power to the
ECM may be disconnected by removing the ECM fuse in the fusebox or
disconnecting the inline EC M power lead at the positive battery terminal.
Disconnecting the negative battery cable to clear codes will achieve the desired
result, but this will also clear other me mory data in the vehicle such as radio
presets or seat memory.

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as much voltage to fire the plug at hi
gh speeds than at idle. The improved
air/fuel ratio control of modern fuel injection combin ed with the higher voltage
output of modern ignition systems will often allow an engine to run significantly
longer on a set of standard spark plugs, but keep in mind that efficiency will
drop as the gap widens (along wit h fuel economy and power).
When you're removing spark plugs, work on one at a time. Don't start by
removing the plug wires all at once, because, unless you number them, they
may become mixed up. Take a minute before you begin and number the wires
with tape.
1. Disconnect the negative battery cabl e, and if the vehicle has been run
recently, allow the engine to thoroughly cool.
2. Carefully twist the spark plug wire boot to loosen it, then pull upward and
remove the boot from the plug. Be su re to pull on the boot and not on the
wire, otherwise the connector locat ed inside the boot may become
separated.
3. Using compressed air, blow any water or debris from the spark plug well
to assure that no harmful contam inants are allowed to enter the
combustion chamber when the spark plug is removed. If compressed air
is not available, use a rag or a brush to clean the area.
Remove the spark plugs when the engine is cold, if possible, to prevent damage
to the threads. If removal of the plugs is difficult, apply a few drops of
penetrating oil or silicone spray to t he area around the base of the plug, and
allow it a few minutes to work.
4. Using a spark plug socket that is equipped with a rubber insert to
properly hold the plug, turn the spar k plug counterclockwise to loosen
and remove the spark pl ug from the bore.
WARNING - Be sure not to use a flexible extension on the socket. Use of a
flexible extension may allow a shear fo rce to be applied to the plug. A shear
force could break the plug off in the cylinder head, leading to costly a\
nd
frustrating repairs.
To install:
5. Inspect the spark plug boot for t ears or damage. If a damaged boot is
found, the spark plug wire must be replaced.
6. Using a wire feeler gauge, check and adjust the spark plug gap. When
using a gauge, the proper size shoul d pass between the electrodes with
a slight drag. The next larger size should not be able to pass while the\

next smaller size should pass freely.
7. Carefully thread the plug into the bor e by hand. If resistance is felt before
the plug is almost completely th readed, back the plug out and begin
threading again. In small, hard to r each areas, an old spark plug wire and
boot could be used as a th reading tool. The boot will hold the plug while
you twist the end of the wire and t he wire is supple enough to twist
before it would allow t he plug to crossthread.

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2. Clean off the marks and coat them wit
h white paint or chalk, if necessary,
so that they may be seen.
3. Run the engine until it reaches no rmal operating temperature, then shut
off the engine.
4. With the ignition OFF, connect a ta chometer to the distributor, and a
timing light with an inductive pickup lead to the No. 1 spark plug wire.
WARNING - Never pierce a secondary ignition wire in order to connect a timing
light. A pierced wire may lead to engine misfiring and driveability problems.
5. To properly set the ignition timing , the EST must be placed in the bypass
mode. a. On the 2.5L engine, refer to t he emission control label for the
procedure.
If the label is missing or unreadable, c ontact your Chevrolet dealer for a
replacement.
b. On 2.8L and 5.0L ca rbureted engines, disconnect the 4-wire EST
connector at the distributor. (Fault code 42 may be set in ECM memory,
and must be cleared once the procedur e is completed). Proceed to Step
7.
c. On 2.8L, 5.0L and 5.7L fuel inje cted engines, with the engine RUNNING
and all accessories off, use a jumper wire to connect diagnostic terminal
B and ground terminal A of the 12-terminal Assembly Line Diagnostic
Link (ALDL) usually located under t he left side of the instrument panel.
DO NOT disconnect the 4-wir e EST connector at the distributor. Aim the
timing light at the timing mark; the li ne on the balancer or pulley will line
up with the timing mark. Increase engine speed and check for timing
advance. If the timing still advances with engine speed, perform Step 6. If
timing does not advance with engi ne speed, proceed to Step 7.
If timing advances with engine speed, it will be necessary to disconnect the
single-wire Set Timing connector. (Faul t code 42 may be set in ECM memory,
and must be cleared once the procedure is completed).
6. Remove the jumper wire from t he ALDL, and shut off the ignition.
Disconnect the Set Timing connector, usually located under the plastic
cover above the heater unit, in the engi ne compartment. (The wire in this
connector is normally Tan/Black.)
7. With the engine running and all accessories off, aim the light at the timing
mark. The line on the balancer or pulle y will line up with the timing mark.
If a change in timing is necessary, loosen the hold-down clamp bolt at
the base of the distributor . While observing the timing mark, rotate the
distributor slightly unt il the line indicates the correct timing. Use the
timing specification on the emi ssion control label in the engine
compartment. If this label is missi ng or damaged, refer to the Tune-Up
Specifications chart in this Section.

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VALVE LASH

All models utilize a hydraulic valve lifter system to obtain zero lash. No periodic
adjustment is necessary. An initial adjustm
ent is required anytime that the lifters
are removed or the valve tr ain is disturbed. This procedure is covered in Engine
& Engine Overhaul .

IDLE SPEED AND MIXTURE ADJUSTMENTS

Mixture adjustments are factory set and sealed; no adjustment attempt should
be made, except by an aut horized GM dealer or reputable shop equipped with
the necessary equipment.

IDLE SPEED
2-BBL CARBURETOR
WITHOUT AIR CONDITIONING
The engine must be running in "Closed Loop" mode (engine fully warmed) when
making all idle speed adjustments. In this mode, the oxygen sensor affects
control of the fuel delivery.
1. Refer to the emission label on the vehicle and prepare the engine for
adjustments (set the timing). Remove the air cleaner and set the parking
brake. Connect a tachometer to the distributor connector.
2. Place the transmission in DRIVE for automatic transmission, or
NEUTRAL for manual transmission; make sure that the solenoid is
energized.
3. Open the throttle slightly to allow the solenoid plunger to extend. Adjust
the curb idle speed to the specified rpm by turning the solenoid screw.
4. De-energize the solenoid by disconnecting the electrical lead.
5. Set the basic idle speed rpm by turning the idle speed screw. After
adjustment, reconnect the solenoid electrical lead.
6. Remove the tachometer and install the air cleaner.

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Fig. 1: Idle speed adjustm ents - 2-bbl carburetor (without air conditioning)
WITH AIR CONDITIONING
The engine must be running in "Closed Loop" mode (engine fully warmed) when
making all idle speed adjustments. In this mode, the oxygen sensor affects
control of the fuel delivery.
1. Refer to the emission label on the vehicle and prepare the engine for
adjustments (set the timing). Remove the air cleaner and set the parking
brake. Connect a tachometer to the distributor connector.
2. Place the transmission in DRIVE for automatic transmission, or
NEUTRAL for manual transmission. Tu rn the air conditioning OFF and
set the curb idle speed by turning the idle speed screw.
3. Disconnect the electrical lead at the A/C compressor, then turn the A/C
switch ON.
4. With the solenoid e nergized, open the throttle slightly to allow the
solenoid plunger to extend.
5. Turn the solenoid screw to adjust to the specified rpm. After adjustment,
reconnect the A/C compressor lead and turn the air conditioning OFF.
6. Remove the tachometer and install the air cleaner.

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Fig. 2: Idle speed adjustm ents - 2-bbl carburetor (with air conditioning)
4-BBL CARBURETOR
WITHOUT AIR CONDITIONING
The engine must be running in "Closed Loop" mode (engine fully warmed) when
making all idle speed adjustments. In this mode, the oxygen sensor affects
control of the fuel delivery.
1. Refer to the emission label on the vehicle and prepare the engine for
adjustments (set the timing). Se t the parking brake. Connect a
tachometer to the dist ributor connector.
2. Place the transmission in DRIVE for automatic transmission, or
NEUTRAL for manual transmission.
3. De-energize the idle speed solenoid by disconnecting the electrical lead.
4. Set the basic idle speed rpm by turning the idle speed screw.
5. Connect a jumper wire from a 12-vo lt power supply to the solenoid.
6. Open the throttle partially to ensure that the solenoid plunger is fully
extended, and allow the throttle lever to close on the plunger.
7. Turn the solenoid plunger to adj ust to the specified rpm. After
adjustment, disconnect the jumper wire and reconnect the solenoid
electrical lead.
8. Remove the tachometer and install the air cleaner.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 662

Fig. 3: Idle speed adjustm ents - 4-bbl carburetor
WITH AIR CONDITIONING
The engine must be running in "Closed Loop" mode (engine fully warmed) when
making all idle speed adjustments. In this mode, the oxygen sensor affects
control of the fuel delivery.
1. Refer to the emission label on the vehicle and prepare the engine for
adjustments (set the timing). Se t the parking brake. Connect a
tachometer to the dist ributor connector.
2. Place the transmission in DRIVE for automatic transmission, or
NEUTRAL for manual transmission. Tu rn the air conditioning OFF.
3. De-energize the idle speed solenoid by disconnecting the electrical lead.
4. Set the basic idle speed rpm by turning the idle speed screw. After
adjustment, reconnect the solenoid electrical lead.
5. Disconnect the electrical lead from the A/C compressor and turn the A/C
switch ON.
6. Open the throttle partially to ensure that the solenoid plunger is fully
extended, and allow the throttle lever to close on the plunger.
7. Turn the solenoid plunger to adj ust to the specified rpm. After
adjustment, reconnect the A/C co mpressor lead and turn the air
conditioning OFF.
8. Remove the tachometer and install the air cleaner.

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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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Fig. 20: Secondary lockout adjus tment on E4ME/E4MC carburetors
MIXTURE CONTROL (M/C) SOLENOID
TRAVEL TEST
These procedures are performed on four barrel models only. Before checking
the mixture control solenoid travel, it may be necessary to modify the float
gauge J-9789-130 or equivalent (used to ex ternally check the float level).
This should be done by filing or grinding sufficient material off the gauge to
allow for insertion down the vertical D-shaped hole in the air horn casting
(located next to the idle air bleed valve cover).
Check that the gauge freely enters the D-shaped vent hole and does not bind.
The gauge will also be used to determine t he total mixture control solenoid
travel.

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MINIMUM IDLE SPEED
The minimum idle speed should onl
y be adjusted under two conditions:
If the throttle body has been replaced.
After every other possible cause for the in correct idle speed has been explored.
There are many possible causes for incorre ct idle speed, most of which require
a high level of diagnostic skill as well as expensive testing equipment. Check
the vehicle for vacuum leaks, incorrect valve or ignition timing, deposit
accumulation in the throttle bore or valve, sticking throttle linkage or bent throttle
valves. If the vehicle will still not idle pr operly after checking these areas, it
should be diagnosed by a professional.
1. Pierce the idle stop screw with an awl. Apply leverage to remove it.
2. Make sure the IAC valve is connect ed. Short the A and B terminals of the
ALDL connector together with a length of wire.
3. Turn the ignition to the ON positi on, but do not start the engine. Wait at
least 30 seconds before proceeding.
4. With the ignition ON, disconnect the IAC valve connector.
5. Separate the set-timing connector. Th is eliminates the possibility of
changes in engine speed due to variations of engine timing.
6. Start the engine and remove t he wire shorting the A and B terminals
together. It may be necessary to hold the throttle open slightly to prevent
the engine from stalling.
7. Allow the engine to reach no rmal operating temperature.
8. Adjust the idle speed to the following: a. 2.8L Engines - 450-550 rp m A/T or 550-650 rpm M/T
b. 3.1L Engines - Refer to the underhood emissions sticker
c. 5.0L and 5.7L TPI engines - 400-450 rpm.
If these figures differ from t hose on the underhood emissions
sticker, always follow the specifications on the emissions sticker.
9. Turn the ignition OFF and connect the IAC valve harness. On models up
to 1989, adjust the Throttle Position Sensor.
THROTTLE POSITION SENSOR (TPS) 1. Install three jumper wires betw een the TPS and the harness connector.
2. Use a digital voltmeter connected to terminals A and B of the TPS.
3. Turn the ignition switch ON , but do not start the engine.
4. Loosen the TPS attaching screws and adj ust the sensor to the following:
a. 2.8L Engines - 0.50-0.60 volts
b. 5.0L and 5.7L TPI Engines - 0.47-0.61 volts
5. Tighten the attaching screws, then check that the reading has not been
disturbed.
6. With the ignition OFF, remove the jumper wires. Reconnect the TPS
harness.