Honda Acura NSX 1991, Service Manual

Page: 274 / 1420

Fuel Supply System
Fuel Pump
Description
Because of its compact impeller design, the fuel pump is installed inside the fuel tank, thereby saving space and simplifying the
fuel line system.
FUEL FILTER
PUMP BRACKET
(Side view)
PUMP ASSEMBLY SECTION (Top view)
DISCHARGE PORT
VALVE
VALVE
I
ARMATURE COIL
I
PUMP CASINO
IMPELLER
The fuel pump is comprised of a DC motor, a circumference flow pump, a relief valve for protecting the fuel line systems, a check
valve for retaining residual pressure, an inlet
and a discharge port. The pump assembly consists of the impeller (driven
the motor), the pump casing (which forms the pumping chamber), and the pump cover.
OPERATION
(1)
When
the engine is started, the main relay actuates the pump, and the motor turns together with the impeller.
Differential pressure is generated the numerous grooves around the impeller.
(2)
Fuel
entering the inlet port flows inside the motor from the pumping chamber and is forced through the discharge port via
the check valve.
lf fuel flow is obstructed at the discharge side of the fuel line, the relief valve will open to bypass the fuel to the inlet port
and prevent excessive fuel pressure.
(3)
When
the engine stops, the pump stops automatically. However, a check valve closes by spring action to retain the residual
pressure in the line, helping the engine to restart more easily.
1 l-98