Fuel Accumulator: Description and Operation

Fig. 5 Fuel Accumulator:

The accumulator is located between the fuel pump and the filter. It improves hot starting by helping to maintain residual fuel pressure when the engine is turned off. It also helps to reduce fuel pump noise by its damping action and protects the metal diaphragms in the fuel distributor from rapid pressure build-up when the pump begins running, Fig. 24.
When the fuel pump begins running, the fuel chamber inside the accumulator is filled through the one-way reed valve, and the diaphragm is forced against the spring until it reaches the stop. Only after the diaphragm reaches the stop does system pressure reach its operating limit.
After the engine is turned off, the spring slowly pushes the diaphragm to the right, forcing about 20 ccs of fuel through a small hole in the reed valve to help maintain residual fuel pressure and avoid vaporization.