Vapor Lock PDF Document

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This is a discription of what happens during a vapor lock condition.  While it represents fuel in a filling station, the concepts are consistant with the fuel sustem in a vehicle.   In  decreasing pressure conditions (suction) fuel gets to the point that it vapouizes after a certain pressure drop.  After it vapourizes the liquid fuel can never be lifted because it has reached it's limit.  Fuel will only vaporize more with more suction. Once this happens the pump simply cavitates and becomes useless.  In a vehicle this usually happens close to the pump or the pump itself cavitates, because most of the extra heat is in the Engine compartment area.  

Use this information along with the fuel blends chart included in this album to see the additional effects of fuel blends.