Chevrolet CAMARO 1979 Service Manual page 646

6C.94 FUEL SYSTEM
F U E L F E E D A N D V A P O R P I P E S
G E N E R A L D E S C R I P T I O N
Fuel feed pipes are secur€d to the underbody with
clamp ând screw assemblies. Flexible hoses are located ât
fuel tank fuel, vapor and return lines and fuel pump. The
pipes should be inspected occasionally for leaks, kinks o.
dents. If evidence of dirt or foreign material is found in
cârbùretor, fuel pump or pip€s, pipeshoùld be disconnected
and blown out. Dirt or foreign mâterial mây be caused by
a dâmaged or omitled fuel strainer in fuel tânk.
ON-CAB SERVICE
Replacement
If replacement of fuel fe€d pipe, vâpor pipe or r€turn
pip€ is required, use only double wrap and brazed steel
tubing meeting GM Specification l23M or its equivalent.
Under no condition use copper or alùminum tubing to
replace steel tubing. Those materials do not have
satisfâctory fatigue dùrability to withstand normai vehicle
GENERAL DÊSCRIPTION
All vehicles are equipp€d with a system design€d to
prevent escape of fuel vapor to the âtmosphere. Vapor
gen€râted by evaporation of fuel in the tânk, p.eviously
exhausted to âtmospherc, is transferred by an emission line
!o the engine compartment. Dùring periods ofinoperâtion,
an activated chârcoal canister locâted in the emission line
stores âny vapor generâted fof consumption during the next
p€riod of operation.
The amount ofvâpordrawn into the €ngine at any time
is small.
With this closed system it is extremely important that
only vâpors be transferred to the engine. To avoid the
possibility ofliquid fuel being drawn into the system, these
following feâtures are inciuded âs part of the total system:
L A fuel tânkovelfill protector is provided on all series
to assure âdequate room for expânsion of liquid fuel volume
with temperature chatrges.
2. A (1) poinl fuel tarlk venting system is provided on
all series to assure that the tank will be vented under âny
conceivable câr attitude. This is accomplished by using a
dome type fuel tark on Sedans and Coupes.
3. To protect the tank ftom mechanical damâge in the
event of excessive internal or extemal pressures resulting
from the operation ofthis closed system, â pressure-vacuum
relief valve, located iû the gâs câp, q,ill control the tânk
ON.CAR SERVICE
Maintenarce requirement is only that the oiled
fibersiass filte. assembled in the bottom of the canister, be
replaced every 30,000 miles (48 000 krn) or 24 months.
Und€r extremeiy dusty conditions, morc frequent âttention
may be required.
REPAIR
l. Do not use fuel hose for pipe repair wilhin 4 inches
of any part of the exhâust system.
2. In repairâble areas, cut fuel hose 4 inch€s longer than
the portion of pipe removed. Use only hose stated for fuel
usage by the manufacturer.
If more thân a 6-inch length of pip€ is removed, use
â combination of steel pipe and hose so that hose lengths
will not be longer than 10 inches.
3. The fùel hose should €xteûd 2 inch€s on €ach pipe
and be clâmped at each end. Pipes must be properly secured
to the frame to pr€vent chafing.
Pressure Checking Evaporativs Control Systsm
1. Engine must be cold and at rcom temperature
2. Remove tank line at canister and observe for liquid
in the line. Hook-up pressure device J-24460 to tank line.
3. Àpply l5' H,O pressure to th€ fuel vapor line.
A. Observe for ercessive loss of pressure.
B. If negligible pr€ssure loss occurs observe fol fuel
vapor smell or fuel loss at points listed in Diagnostics under
Possible Cause.
C. Remove fuel filler cap and observe for pressure jn
tank.
4. Remove fuel câp and check vent line for
Canister and Fillo.
Romoval
1. Note installed position of hoses on canister'
2. Disconnect hoses lrom Lop of canister,
3. Loosen clamps and remove canister,
4. If replacing filter, pull out filter from bottom of
canist€r with your fingers.
tnsp€clion
l. Check hose connection openings. Assure that they
2. Check operation of purge valve by applying vacuum
ro the vâlve. A good talte will hold vâcuum.
lnstallation
1. Inslall new filter.
2. Install canister and tighten clâmp.
3, Connect hoses iû same order.
E V A P O R A T I V E C O N T R O L S Y S T E M ( E C S )