Content .. 32 33 34 35 ..

Mazda RX7. Manual - part 34

CHOKE - ELECTRIC ASSIST

Article Text

1983 Mazda RX7

For www.iluvmyrx7.com

Sunday, August 26, 2001 04:58PM

ARTICLE BEGINNING

1983 Exhaust Emission Systems
MAZDA RX7 CHOKE RETURN & HOT START ASSIST SYSTEMS

DESCRIPTION

The Choke Return system prevents the choke knob from being
left unreturned to prevent overheating of the exhaust system. The Hot
Start Assist system opens the throttle valve partially during
cranking of warm engine to optimize air/fuel mixture to improve
starting.
The choke return system components include No. 1 water
temperature switch, choke relay, choke magnet and choke switch. The
hot start assist system components include No. 1 water temperature
switch, hot start relay and hot start motor.

OPERATION

CHOKE RETURN SYSTEM

When cold engine is started with assist of choke knob, the
knob is held in pulled position by the choke magnet. Full release of
choke knob is achieved as engine coolant temperature reaches 158

(70

C). The No. 1 water temperature switch stops the flow of

electrical current to magnet and the choke knob is released.

HOT START ASSIST SYSTEM

During cranking of a warm engine, the No. 1 water
temperature switch provides power to the hot start relay when starter
is engaged. When hot start relay is activated, the hot start motor
pulls the hot start cable which opens the throttle valve.

CHOKE - ELECTRIC ASSIST

Article Text (p. 2)

1983 Mazda RX7

For www.iluvmyrx7.com

Sunday, August 26, 2001 04:58PM

Fig. 1: Choke Return and Hot Start Assist Systems

TESTING

CHOKE RETURN SYSTEM

1) With engine cold and ignition switch "OFF", pull choke
knob out fully. Choke knob should return automatically.
2) Connect tachometer to engine. Start engine and set engine
speed at 2000 RPM with choke knob. With engine running, choke knob
should automatically return when engine temperature indicator is in
position shown in Fig. 2.

Fig. 2: Engine Temperature Indication for
Release of Choke Knob

CHOKE - ELECTRIC ASSIST

Article Text (p. 3)

1983 Mazda RX7

For www.iluvmyrx7.com

Sunday, August 26, 2001 04:58PM

CHOKE MAGNET

Disconnect electrical connector from choke switch. Using an
ohmmeter, check continuity between terminals. Continuity should exist
between terminals No. 6 and No. 8. See Fig. 3.

Fig. 3: Choke Switch Terminal Numbering

HOT START ASSIST SYSTEM

NOTE: Before replacing hot start motor or relay, check No. 1 water
temperature switch as outlined in "Mazda RX7 Auxiliary
Control Device" article in this section.

1) Inspect hot start assist cable and linkage for proper
installation, no binding or sticking, and full return. Warm engine to
normal operating temperature and stop engine.
2) Disconnect leading and trailing primary wires from
ignition coils. Crank engine. Hot start lever should open throttle
valve. If hot start system does not respond as outlined, check hot
start assist relay.

HOT START ASSIST RELAY

1) Disconnect electrical connector from hot start relay.
Using an ohmmeter, check continuity between terminals. Continuity
should exist between terminals No. 1 and No. 5 without power applied.
Continuity should not exist between terminals No. 1 and No. 3 without
power applied.
2) Connect battery power to relay (positive to terminal No.
2, negative to terminal No. 4). With battery power applied,
continuity should exist between terminals No. 1 and No. 3. Continuity
should not exist between terminals No. 1 and No. 5 with power applied.

Fig. 4: Hot Start Assist Relay
Terminal Numbering

CHOKE - ELECTRIC ASSIST

Article Text (p. 4)

1983 Mazda RX7

For www.iluvmyrx7.com

Sunday, August 26, 2001 04:58PM

HOT START ASSIST

CABLE ADJUSTMENT

1) Remove hot start assist cable lock spring from cable
bracket. Slowly pull outer cable until hot start lever just touches
stopper lever. Check clearance between cable bracket and cable lock
nut.
2) If clearance is not .02-.08" (0.5-2.0 mm), adjust
clearance by turning lock nut. Recheck clearance and install lock
spring.

Fig. 5: Adjusting Hot Start Relay Cable

END OF ARTICLE

Content .. 32 33 34 35 ..