Auxiliary Acceleration Pump (Aap) System - Toyota 4-Runner 1985 Repair Manual

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EMISSION CONTROL SYSTEMS (CARB.) - Auxiliary Systems
. Fed. and Canada
5. Auxiliary Acceleration Pump
(AAP) System
AAP
A03079
Calif.
Acceleration Nozzle
AAP
EC-61
EC1064
EC3805
The carburetor air-fuel mixture is very lean. When accelerating with a cold engine, the main acceleration pump capacity
is insufficient to provide good acceleration. The AAP system compensates for this by forcing more fuel into the accelera-
tion nozzle to obtain better cold engine performance.
Coolant Temp. BVSV Engine
Intake Vacuum Diaphragm in AAP Fuel
Constant RPM HIGH
Drawn into AAP
Pulled by vacuum
Chamber
Below 55°C OPEN
(131°F)
(J-L)
Accelerataion LOW
Returned by spring Forced into acceleration
tension Nozzle
Above 74°C CLOSED
No operation
(165°F)
(J-L)
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