Fuel system that prevents vapor lock in powertrains converted to run on a volatile alternative fuel

A high pressure fuel pump, comprising:

• a housing;
• a low pressure chamber disposed within the housing;
• a compression chamber disposed within the housing;
• a piston configured to reciprocate within the compression chamber and pressurize fuel within the compression chamber;
• a high pressure outlet in fluid communication with the compression chamber and configured to discharge pressurized fuel;
• a supply valve configured to control fluid communication between the low pressure chamber and the compression chamber;
• a low pressure inlet configured to admit fuel into the low pressure chamber;
• a low pressure outlet configured to discharge fuel from the low pressure chamber, wherein the low pressure outlet permits flow from the low pressure chamber independently of the supply valve;
• and
• a flow regulator having an inlet fluidically coupled to the low pressure outlet, the flow regulator configured to control flow from the low pressure chamber through the low pressure outlet.