FixVault

Automatic Temperature Control Air Cleaner

When air temperatures are above 100°F, the sensor acts to partially open valve. When air temperatures get higher, and exceed 118°F, the valve fully opens, stopping the supply of hot air from the exhaust manifold and allowing under hood air into the carburetor. In this way the heated and non-heated air is mixed so as to keep the carburetor air temperature at about 109°F. During heavy throttle operation, the valve opens the cooler air passage regardless of inlet temperature.

NOTE: The following tables show the operation of each control switch under vehicle operating conditions. Two charts are shown; one for manual transmissions with gear switches, and one for automatic transmissions with speed detector and speed switch.
OPERATING CONDITION TEMPERATURE SENSING SW THROTTLE SW THIRD GEAR SW SPARK TIMING
(1)Switch detecting close throttle position Switch detecting wide open throttle position "Advanced" "Retarded"
Engine start and warming up (cold start) OFF (below 34°F) ON (above 50°F) ON ON OFF X --
Engine start (hot start) OFF ON OFF X --
Idling OFF ON OFF X --
Cruising or accelerating in 3rd gear with partially open throttle ON ON ON X (below 34°F (above 50°F)X
Cruising or accelerating in 1st, 2nd, and 4th "gear with partially open throttle ON ON OFF X --
Cruising or accelerating with wide open throttle ON OFF ON (3rd) OFF (1st, 2nd, 4th) X --
Coasting OFF ON ON (3rd) OFF (1st, 2nd, 4th) X --
Remarks When the temperature of passenger compartment is below 34°F, this switch is "OFF." And when the temperature is above 50°F, the switch is "ON." When the throttle valve is nearly closed, this switch is "ON." When the valve is slightly opened, the switch is "OFF" When the throttle valve is opened more than 30 degrees for PL510 and WPL510, and 40 degrees for PL521, this switch is "OFF." When the shift lever is in 3rd gear, this switch is "ON." And when the lever is in another gear position, the switch is "OFF." When the "retarded" spark timing is provided, HC emission is reduced.
(1) In case of Datsun PL521, this section should be replaced by accel. switch.

2SM018 

SPARK CONTROL SYSTEM OPERATION (510 & 521 MANUAL TRANS.) 

OPERATING CONDITION TEMPERATURE SENSING SW THROTTLE SW SPEED SW SPARK TIMING
Switch detecting close throttle position Switch detecting wide open throttle position "Advanced" "Retarded"
Engine start and warming up (cold start) OFF (below 34°F) ON (above 50°F) ON ON OFF X --
Engine start (hot start) OFF ON OFF X --
Idling OFF ON OFF X --
Cruising or accelerating over 13 mph with partially open throttle ON ON ON X (below 34°F) (above 50°F X
Cruising or accelerating under 13 mph with partially open throttle ON ON OFF X --
Cruising or accelerating with wide open throttle ON OFF ON (above 13 mph) OFF (below 13 mph) X --
Coasting OFF ON ON (above 13 mph) OFF (below 1.3 mph) X --
Remarks When the temperature of passenger compartment is below 34°F. this switch is "OFF." And when the temperature is above 50°F, the switch is "ON." When the throttle valve is nearly closed, this switch is "ON." And when the valve is slightly opened, the switch is "OFF." When the throttle valve is open more than 35 degrees, this switch is "OFF." When the car speed is under 13 mph, this switch is "OFF." And the speed is over 13 mph, the switch is "ON." When the "retarded" spark timing is provided, HC emission is reduced

2SM019 

SPARK CONTROL SYSTEM OPERATION 510 AUTO. TRANS.