engine CHEVROLET CAMARO 1982 Repair Guide

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 666
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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Fig. 3: Be careful not to spill fuel when removing the pump from the engine
TESTING
To determine if the pump is in good condition, tests for both volume and
pressure should be performed. The test s are made with the pump installed, the
engine at normal operating temperatur e and operating at idle speed. Never
replace a fuel pump without first performing these simple tests.
Ensure the fuel filter has been changed at the specified interval. If in doubt,
install a new filter first. Always check fo r broken or deteriorated fuel hoses. If a
line has a crack or split, the pump may be operating properly, but the pump will
only draw air, not fuel.
PRESSURE TEST
1. Disconnect the fuel line at the carburetor, then connect a fuel pump
pressure gauge. Ensure the carburet or float bowl has a sufficient amount
of gasoline.
2. Start the engine and c heck the pressure with the engine at idle. If the
pump has a vapor return hose, squeeze it off so that an accurate reading
can be obtained. Pressure should be 5
1/2-61/2 psi.
3. If the pressure is incorrect, replace t he pump. If it is within specifications,
go on to the volume test.
VOLUME TEST

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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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the idle speed or mixture,
adjust the idle and mixture again when you are
finished.
Before you make any carburetor adjustment s make sure that the engine is in
tune. Many problems which are thought to be carburetor related can be traced
to an engine which is simply out-of-tune. Any trouble in these areas will have
symptoms like those of carburetor problems.
ADJUSTMENTS
FAST IDLE
ROCHESTER E2SE 1. Refer to the emission label and pr epare the vehicle for adjustment.
2. Place the fast idle screw on the highest step of the fast idle cam.
3. Turn the fast idle screw to obtain the fast idle speed.
ROCHESTER E4ME AND E4MC
The fast idle adjustment must be perform ed according to the directions of the
emissions label.
FLOAT AND FUEL LEVEL
ROCHESTER E2SE
1. Remove the air horn and gasket.
2. While holding the retainer in place, push the float down lightly against the
needle.
3. Place a measuring gauge on the float at the farthest point from the float
hinge.
4. To adjust, remove the float and bend the arm up or down. Also check the
float alignment.
5. Install the air horn and gasket.

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With the engine OFF and the air cleaner re
moved, measure the control solenoid
travel as follows:
1. Insert a modified float gauge J- 9789-130 or equivalent down the D-
shaped vent hole. Press down on the gauge and release it.
2. Observe that the gauge moves freel y and does not bind. With the gauge
released (solenoid in the up position), be sure to read it at eye level and
record the mark on the gauge (in inc hes/millimeters) that lines up with
the top of the air hor n casting (upper edge).
3. Lightly press down on the gauge until bottomed (solenoid in the down
position). Record (in inches/millimeters) the mark on the gauge that lines
up with the top of the air horn casting.
4. Subtract the gauge up dimension from gauge dimension. Record the
difference (in inches/millimet ers). This difference is total solenoid travel.
5. If total solenoid travel is not within
3/32-5/32 in. (2.4-3.9mm), perform the
mixture control solenoid adjustment s. If the difference is within
specifications, proceed to the id le air bleed valve adjustment.
If adjustment is required, it will be necessary to remove the air horn and drive
out the mixture control solenoid screw pl ug from the under side of the air horn.

Fig. 21: Checking the solenoid plunger travel
ADJUSTMENTS
Before making adjustment to mixture cont rol solenoid, verify that the plunger
travel is not correct.
1. Remove air horn, mixture control solenoid plunger, air horn gasket and
plastic filler block, using normal service procedures.
2. Check carburetor for caus e of incorrect mixture:
a. M/C solenoid bore or plunger worn or sticking
b. Metering rods for incorrect part number, sticking or rods or springs
not installed properly

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b. Install plug, with hollow end do
wn, over the rich mixture stop
screw access hole and drive plug into place so that the top of the
plug is
3/16 in. (4.7mm) below the surface of the air horn casting.
Plug must be installed to retain screw setting.
12. To check the M/C solenoid dwell, first disconnect vacuum line to the
canister purge valve and plug it. Ground diagnostic TEST terminal and
run engine until it is at normal operat ion temperature (upper radiator
hose hot) and in closed loop.
13. Check M/C dwell at 3000 rpm. If within 10-50 degrees, calibration is
complete. If higher than 50 degrees, chec k the carburetor for a cause of
rich condition. If below 10 degrees, look for a cause of lean engine
condition such as vacuum leaks. If none are found, check for the cause
of a lean carburetor.

Fig. 22: Installing the mixture control solenoid gauging tool

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IDLE AIR VALVE
A cover is in place over t
he idle air bleed valve. Also , the access holes to the
idle mixture needles are s ealed with hardened plugs. This is done to seal the
factory settings, during original equipment production. These items are NOT to
be removed unless required for cleaning, part replacement, improper dwell
readings or if the System Performance Check indicates the carburetor is the
cause of the trouble.
ROCHESTER E4ME AND E4MC
1. With engine OFF, cover the internal bowl vents and inlet to bleed valve
and the carburetor air intakes with maski ng tape. This is done to prevent
metal chips from entering.
2. Carefully drill rivet head of idle air bleed cover, with 0.110 in. (2.8mm) drill bit.
3. Remove rivet head and all pieces of rivet.
4. Lift cover off air bleed valve and bl ow out any metal shavings, or use a
magnet to remove excess metal.
CAUTION - Always wear eye protection when using compressed air.
5. Remove masking tape.
6. Start engine and allow it to reac h normal operating temperature.
7. Disconnect the vacuum hose from t he canister purge valve and plug it.
8. While idling in D for automatic transmission or N for manual
transmission, slowly turn the valve c ounterclockwise or clockwise, until
the dwell reading varies within the 25-35 degree range, attempting to be
as close to 30 degrees as possible.
Perform this step carefully. The air bleed valve is very sensitive and should be
turned in
1/8 turn increments only.
9. If the dwell reading d oes not vary and is not within the 25-35 degree
range, it will be necessary to remove the plugs and to adjust the idle
mixture needles.

GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 694
IDLE MIXTURE
E2SE CARBURETORS
1. Remove the carburet or from the engine.
2. Remove the plugs coveri ng the idle mixture needles.
3. Turn the mixture needle in until slight ly seated, then back it out 4 turns.
4. If the plug in the air horn coveri ng the idle air bleed has been removed,
replace the air horn. If the plug is still in place, do not remove it.
5. Remove the vent stack screen a ssembly to gain access to the lean
mixture screw.
6. Using tool J-28696-10 or equivalent, turn the lean mixture screw in until
lightly seated, then back out 2
1/2 turns.
7. Install the carburetor on the engine.
8. Disconnect the bowl vent line at the carburetor.
9. Disconnect the EGR hos e and canister purge hose at the carburetor.
Cap the ports on t he carburetor.
10. Find the hose from port D of the carburetor to the temperature sensor
and secondary vacuum break thermal vacuum switch. Disconnect and
plug the vacuum hose going to the air cleaner.
11. Connect the positive lead of a dwell me ter to the mixture control solenoid
test lead (green connector). Connect the other lead to ground. Set the
meter to the 6 cylinder position.
12. Run the engine on the high step of the fast idle cam until the cooling fan
starts to cycle.
13. Run the engine at 3,0 00 rpm and adjust the lean mixture screw slowly.
Allow the reading to stabilize, obtain an average dwell of 35 degrees. It is
normal for the dwell to vary in a narrow range.
14. Return to idle.
15. Adjust the idle mixt ure screw to obtain an av erage dwell of 25 degrees.
Allow time for the reading to stabilize.
16. Run the engine at 3,000 rpm and not e the dwell reading. It should be
varying with an average reading of 35 degrees. If it does not, repeat the
earlier steps.

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Fig. 27: Idle mixture needle plug removal
E4ME CARBURETORS (ELECTRIC CHOKE) 1. Using tool J-29030, BT-7610-B, or equivalent, turn both idle mixture
needles clockwise until they are lightly seated, then turn each mixture
needle counterclockwise 3 turns.
2. Reinstall carburetor on engine using a new flange mounting gasket, but
do not install air cleaner and gasket at this time.
3. Disconnect the vacuum hose to canister purge valve and plug it.
Readjust the idle air bleed valve to finalize correct dwell reading.
4. Connect the positive lead of a dwell me ter to the mixture control solenoid
test lead (green connector). Connect the other lead to ground. Set the
meter to the 6 cylinder position.
5. Start engine and run unt il fully warm, then repeat the idle air bleed valve
adjustment.
6. If unable to set dwell to 25-35 degrees and the dwell is below 25
degrees, turn both mixture needles counter clockwise an additional turn. If
dwell is above 35 degrees, turn both mixture needles clockwise an
additional turn. Readjust idle air bleed valve to obtain dwell limits. Repeat
as needed.
7. After adjustments are complete, seal the idle mixture needle openings in
the throttle body, using silicone sealant, RTV rubber, or equivalent. The
sealer is required to discourage unnecessary adjus tment of the setting
and to prevent fuel vapor loss in that area. Reconnect canister vacuum
hose.
8. On vehicles without an Idle Load Co mpensator (ILC), adjust curb idle
speed if necessary.
9. Check, and if necessary, adjust fa st idle speed as described on Vehicle
Emission Control Information (VECI) label.

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Fig. 28: Lean mixture and idle mixture screw adjustment
E4MC CARBURETOR (HOT AIR CHOKE) 1. Using tool J-29030-B, BT-7610-B, or equivalent, turn each idle mixture
needle clockwise until lightly seated, then turn each mixture needle
counterclockwise 3 turns.
2. Reinstall carburetor on engine, using a new flange mounting gasket, but
do not install air cleaner or gasket at this time.
3. Disconnect vacuum hose to c anister purge valve and plug it.
4. Connect the positive lead of a dwell me ter to the mixture control solenoid
test lead (green connector). Connect the other lead to ground. Set the
meter to the 6 cylinder position.
5. Start engine and allow it to reac h normal operating temperature.
6. While idling in D ( N for manual transmission), adjust both mixture
needles equally, in
1/8 turn increments, until dwell reading varies within
the 25-35 degree range, attempting to be as close to 30 degrees as
possible.
7. If reading is too low, turn mixtur e needles counterclockwise. If reading is
too high, turn mixture needl es clockwise. Allow time for dwell reading to
stabilize after each adjustment.
After adjustments are complete, seal t he idle mixture needle openings in the
throttle body, using silicone sealant, RTV rubber, or equivalent. The sealer is
required to discourage unnece ssary readjustment of the setting and prevent fuel
vapor loss in that area.
8. On vehicles without a carburetor -mounted Idle Load Compensator (ILC) ,
adjust curb idle speed if necessary.