Fuel Accumulator: Description and Operation

Fuel Accumulator:

Fuel Pump And Filter Mounting Bracket:

The Fuel Accumulator is located under the rear of the car mounted on a common bracket with the fuel pump and fuel filter. The Fuel Accumulator dampens fuel pressure surges and holds residual fuel pressure in the system when the engine is shut off. The Fuel Accumulator's damping action protects the fuel distributor from the rapid build-up of fuel pressure during start-up, and reduces fuel pump noise when the engine is running. When the engine stops, the Fuel Accumulator holds fuel pressure to help prevent vapor lock and improve hot restarts.

The main components of the Fuel Accumulator are a spring and a diaphragm that separates the spring chamber from the fuel chamber. When the fuel pump begins running, pressure builds in about 1 second as fuel fills the fuel chamber and presses the diaphragm against a stop. At pump shut off, the pressure drops rapidly to about 30 psi (2.10 kg/cm2). This residual pressure is maintained by the force of the spring pressing against the diaphragm and the fuel in the fuel chamber. The Fuel Accumulator holds pressure for a half hour or more to prevent vapor lock caused by fuel vaporization in the fuel lines of a hot engine.