Accelerator Pump: Description and Operation

The Temperature Compensated (rate-sensitive) Pump, will allow delivery of a large pump capacity to facilitate cold engine requirements and a smaller pump capacity during warm engine operation. The amount of fuel delivered during warm engine operation is a function of the rate at which the accelerator pedal is opened (fast opening-low capacity/slow opening-higher capacity). The design incorporates a bypass bleed controlled by a vacuum operated valve. Normally, the input signal controlling the valve position is manifold vacuum switched by a PVS located in the engine coolant system.


The valve is normally closed when no vacuum is applied allowing full pump capacity during the cold operation. With vacuum applied, the pump functions as a rate sensitive valve controlling the amount of fuel bypassed back to the fuel bowl and not delivered to the intake air stream.