Chevrolet CAMARO 1979 Service Manual page 579

FUEL SYSTEM 6C.27
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F i s . 6 C 2 - 3 - M o d e l l d e n t i f i c â r i o n
engine is not running, the canister vapor vent valve is open
allowing fuel vapon from the carburetor floar bowl to pass
on into the cânister where they are slored until purged.
Purging ofthe canister is accomplished through the Posirive
Crânkcâse Ventilation (P.C.V.) Syst€m.
All models have include a conventional exhâùsr heared
air or a el€ctrically operared rhermosratic coil assembly,
mounted on the carburetor float bowl, 1o control choke
ûixtures after engine stân and during cold driveaway. A
single vacuum brcâk unitcontrols choke valveopening after
initiâl engine start-
For ease of service, âlphabetical code lettefs are cast
in the air horn ând float bowl at external rube locations to
idenrify âir and vacuum hose connectjons.
The carburetor model identification is stamped
vertically on the left reâr corner of the float bowl (Fig. 6C2-
3). If replacing the float bowl, follow the manufâcturer's
instructions contained in the se ice package so that the
identificâtion number can be transferred to the new floar
An Exhaust Gas Recilculation (E.G.R.) system is used
on all applications to control oxides of nitrogen.
The vacuùm supply ports nec€ssary to op€rate the
recirculation valve âr€ located in the throttle body and
connect through a channel to a tube in the throttle body.
This tube is connected by â rubber hose to the E.G.R. valve.
See Idle System (Fig.6C2-5) for port location ând operâtion.
On M2M models us€d with âir conditioning
applicârions, an electricâlly operated A/C idle speed-up
solenoid is used to mâintâin proper idle speed when the air
conditioning is in operation.
Incorporated in th€ Model M2M carburetors are six
bâsic aysrems. They are noar, idle. mâin metenng. power,
pump, and choke (Figs. 6C2-4 thto,rgh 6C2-9\.
NOTICE: The ins€rt is requir€d to reduce fuel slosh
in the float bowi.
An integfâ1, 2-inch pleâted paper fu€l filter with check
valve is mounted in the front of rhe floar bowl behind the
fuel inlet nut to give maximum filtration ofincoming fuel.
The check valve is used to shut ofï firel flow io the
carbùretor and prevent fuel leaks if â ca. roll-over should
The Model 210 ùses a plastic float with a windowless
type needle seat for better fuel handling. The float needle
ls Vilon tipped and uses a pull clip for ûaximum fuet
deliv€ry to the floât bowl. A plastic filler block is used above
the float châmber to redùce fuel slosh in the float bowl.
A tube (Location T) is used in the air horn which
through a hose connects dir€ctly to â vacuùm operated
vapor vent valve locâted in the vapo. canister. When the
O N - C A R S E R V I C E
CARBURETOR ADJUSTMENTS
Refer to Figures 6C2- l0 through 6C2- 15 for carburetor
adjustment procedures and sp€cifi cations.
CHECKING ELECTRIC CHOKE
L Allow choke to cool so that when thrcttle is oDe ed
slightly choke blade fuliy closes.
NOTICE: This ch€ck should be perfomed at an
ambi€nt temperâturc of 60 to 80'F (15 to 27'C).
2. Stan engine and determine time for choke blade to
reach ful1 open position. (Stârt timer wh€n engine stârts).
3. If the choke blade fails to open fr. ly within 3.2
minutes proceed wilh steps 4 and 5 below.
4, Check voltage at the choke heater connection:
(Engine musi be runnins).
â. If the voltage is approximately 12-15 volts, replace
the electic choke unit.
b. If the voltâge is low or zero, check â11 wires and
connections. If th€ connections attheoil pressure switchâre
faulty, the oil warning light will be off with the key 'oû"
and engine off Ifthe fuse is blown, the radio or tùrn sigDal
indicator will be inoperative. Repair wires or replace fuses
5. If steps 4a and 4b do not correct, replace oil pressurc
switch.
NOTICE: No gasket is used between the choke cover
and the choke housiûg due to grounding requirements.
Ch€cking Solenoid
L Turn on ignirion, bur do nor slart engjne.
2. Tùrn A/C to ''on" position.
3. Open throttle to allow solenoid plunger to extend,
close throttle.
4. Disconnect lead at solenoid. Solenoid plunger should
drop away from throttle lever.
5. Conn€ct solenoid lead. Plungershould moveoutand
contâct the throttle lever. Solenoid may nol be strong
enough to open the throttle, but the plunger shoùld mov€.
6. lf plunger does not move in and oùt as leâd is