Vapor lock can also occur in other types of pumping systems where volatile liquids are being handled. One of the most frightening and dangerous losses of braking efficiency, vapour lock is connected with brake fluid. Vapor lock problems are most likely to occur in the late spring on unseasonably warm days, before the more volatile winter grades of gasoline have been replaced by the less volatile spring and summer grades (see v o la t ilit y). In a suction system, the action of the dispenser pump creates a vacuum that pulls gasoline from an underground storage tank and through the piping to the dispenser. Automotive engines are more likely to experience vapor lock during an acceleration that follows a short shutdown period. A condition that sometimes occurs during hot-weather months in suction pumping systems, and which interferes with the flow of gasoline through the system. Factors favoring vapor lock are high ambi e nt temperatures, low ambient pressure, volatile gasoline, and vehicle designs where heat from the engine can create high fuel line temperatures. The engine will usually stall, but in less severe cases may accelerate sluggishly or kn o c k due to an excessively lean fuel mixture. Critical care Obstruction of blood flow due to a trapped bolus of gas in a tube or vessel. Vapor lock is a problem caused by liquid fuel changing state to gas while still in the fuel delivery system of gasoline-fueled internal combustion engines. The engine will usually stall, but in less. Vapor lock occurs when the fuel pump, which is designed to pump liquid, loses suction as it tries to move fuel vapor. Vapor lock occurs when the fuel pump, which is designed to pump liquid, loses suction as it tries to move fuel vapor. Please, if there's any flaws in what I'm stating, correct me! That's the entire purpose of this post, I need education when it comes to vapor lock.Vapor lock - disruption of fuel movement to a g a so lin e engine caused by excessive vaporization of gasoline. With a diesel you can get an airlock and particularly with mechanical fuel injection where the pocket of air in the high pressure injector pipes is larger than the quantity. Dan ran to get away from the cops, but he vapor locked before he. Answer (1 of 5): Don't usually get vapour lock with a diesel but you can with a petrol as the fuel vaporises fairly easily. One question, can vapor lock occur when an engine is running? If so, what's the appropriate procedure to take? Run the aux fuel pump? I know it can occur before start-up, and I'm assuming that it then takes quite some time to restart the engine as the vaporized fuel is forced out of the line. A pocket of vaporized gasoline in the fuel line of an internal-combustion engine that obstructs the normal flow of fuel. When you are totally out of shape and over exert yourself, to the point you can hardly breath. Also, this can be caused by enough air being trapped in the fuel line either by improper venting or running a tank dry before switching. Thus, two things happen: one, the fuel pumps aren't designed to efficiently pump fuel vapors, and two, the pressure in the fuel lines as a result of the vapor attempting to occupy more space can cause the fuel not to flow through the injector and into the engine. A condition that sometimes occurs during hot-weather months in suction pumping systems, and which interferes with the flow of gasoline through the system. In a fuel injected aircraft, a hot engine or nearby exhaust manifold can cause the liquid fuel being pumped through the fuel lines to vaporize, or as most people say, boil over. My understanding of vapor lock is the following: