Jeff Smith: Vapor lock is a term used to describe when fuel changes from a liquid to a vapor before it arrives at the carburetor. Most enthusiasts tend to focus on the pressure side of the fuel delivery system when the real problems are more likely located on the low pressure or inlet side of the pump. But first, it’s important to mention that fuel is designed to vaporize. It’s the fuel that has vaporized that supports combustion. Gasoline is a complex mix of light and heavy hydrocarbons that are designed so the light or volatile portion of the fuel vaporizes quickly, even at normal or low temperatures. This allows a cold engine to start quickly. So we’re dealing with a fuel that is designed to vaporize. Now let’s imagine we have a very warm day of 90 degrees. At this temperature, roughly 20 percent of the fuel has already converted to a vapor as measured at normal atmospheric pressure. Now let’s introduce a mechanical fuel pump into this application where the pump must “pull” fuel from the tank all the way to the engine where it can now push the fuel into the carburetor. Before we go any further, it’s important to note that pumps do not “suck” the fuel. The pump creates low pressure on its inlet side and higher atmospheric pressure pushing down on the fuel in the tank (because the tank is vented), is what pushes the fuel toward the pump. However, the fuel is still subject to lower atmospheric pressure. This reduced pressure also lowers the boiling point of any liquid and especially gasoline which means a higher percentage of fuel will vaporize. So we have hot fuel (that has been percolating in the fuel tankexposed to heat coming off the pavement that might be 120 degrees F, and now we subject the fuel to lower pressure in the fuel line. Then, if there is any kind of restriction in the fuel line between the fuel in the tank and the pump at the front of the vehicle, this restriction will create even lower pressure in the line heading to the pump inlet. For example, an older car with an original and a fossilized sock stuck on the fuel inlet in the tank could cause such a restriction. Or perhaps the fuel line has been kinked or bent or the existing tank vent has become plugged or restricted. Any combination of these situations will force the pump to work harder and create lower pressure on the inlet side in an effort to continue to pump the fuel. This creates a perfect scenario for vapor lock. What really happens is that enough fuel turns to vapor that a pump designed to push liquid is now trying to pump vapor. That won’t work very well and the result is that fuel pressure drops very low as only a small portion of the fuel is still in liquid form and is not sufficient to feed the engine. So the engine stumbles and dies.Ī common and successful remedy for inlet side vapor lock problems is to place an electric pumpinline near the tank inlet. If you think about this, this is an excellent solution because it minimizes the distance the mechanical pump must work to move fuel under low pressure. Detectives were working Wednesday to determine where the drugs and guns came from.With an electric pump, the fuel pump has now pressurized the fuel during a majority of the distance it must travel, greatly reducing its exposure to low pressure. Police say since all four boys are juveniles, their names will not be released. If parents have guns in their household, please be responsible to keep them locked up and away from children at all times. In a news release, Greenfield Police Department Captian Schwamberger calls on parents in the community to know what their kids are doing and who they are with. They both face charges of illegal possession of a firearm by a minor and dealing marijuana. The other two teens were taken and transported to an out-of-county juvenile detention facility. One 16-year-old and one 17-year-old were released to their guardians and face charges of illegal possession of marijuana. Two 16-year-olds and two 17-year-olds were arrested. During the traffic stop, police say probable cause was established and began to search the vehicle, a release said Wednesday.ĭuring the search, detectives found two guns, ammunition, multiple THC vape cartridges, and several hundred dollars in cash. On Monday, Greenfield detectives were working proactive drug and firearms crime enforcement and stopped a vehicle in the area of State Street and New Road. (WISH) - Four teenage boys were arrested Monday during a traffic stop in Greenfield after officers found drugs and guns in the vehicle, police say.
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