Electronic Fuel Pump Primer

No matter the use — construction, industrial, agricultural, lawn and grounds maintenance, power and light generation, military or marine auxiliary power application — when the key is turned, the switch is flipped or the starter cord is pulled, a  machine’s engine is dependent upon its fuel supply system. This fuel supply system is composed of a fuel tank, fuel pump, filter, fuel lines, vapor recover lines, carburetor or injection components and all the fuel system vents and evaporative emission control systems that provide fuel supply and fuel metering functions.

A primary component of the fuel supply system on today’s compact equipment is the fuel pump. Simply

stated: The purpose of the fuel pump is to draw fuel from the fuel tank and deliver it to a fuel injector or carburetor. Before the wide acceptance of electronic fuel injection, most carbureted engines used mechanical or diaphragm type pumps to move fuel. As technology advances from carburetor toward fuel injection systems, these mechanical diaphragm type pumps are either being replaced or “supported” by solid state electronic fuel pumps which feature the reliability of no bearings, electrical contacts or diaphragms to wear out or fatigue.

An electronic fuel pump can act as the system’s main fuel pump or be used as a priming pump or lift pump in conjunction with an engine’s mechanical pump or fuel injection pump.  These electronic fuel pumps are engineered to be compatible with fuels such as gasoline, diesel, bio-diesel, E85, blended alcohol and fuel additives. They can be conveniently mounted close to the fuel tank either above or below the liquid level.

In gasoline applications when gravity feed systems can no longer be used due to engine size or when the distance between the fuel supply and the engine is too far, low pressure electronic fuel pumps are installed to provide consistent pressure and fuel flow to the carburetor. The size and style of the pump is typically determined by factors such as how much fuel is needed, at what psi it must be delivered and how far the pump is mounted from the tank. It may also be advisable to consider the use of a fuel pump that has the added engineering features such as an internal check valve which provides greater lift capabilities and is capable of “checking” the fuel between the pump and the carburetor when the pump is powered down; or, an electronic fuel pump which has an internal positive shutoff valve to stop the flow of fuel from the fuel supply to the pump when power is turned off. In many applications, electronic fuel pumps incorporating both types of valves may be deemed necessary.

In diesel applications, there are many variables which must be considered when choosing the proper electronic fuel pump. For example: On what type of compact equipment is the electronic fuel pump to be installed? Does it require a 12- or 24-volt system? What are the psi, gph, dry lift and working pressure requirements? Does it require check valves or positive shutoff valves or both? Is there a return fuel line back to the tank? Is it used as the main fuel pump or will it supply fuel to a mechanical pump or injection pump. Will the electronic fuel pump be turned off after start up and if so, will fuel be pulled through the pump when powered off? Only after all these types of questions have been answered can the correct original equipment manufacturer (OEM) or aftermarket electronic fuel pump be selected and installed.

In a priming application, where the fuel pump is only used during start up or when the fuel system has been drained completely of fuel, a priming pump is installed to prime the fuel system instantly and push fuel into the injection system. This allows the engine to start quickly and avoids unnecessary engine cranking. The ability to start instantaneously can avert engine damage and the resulting repair and downtime costs.  

It is essential that today’s high performance diesel engines equipped with a fuel rail system have access to a

large volume of fuel at the turn of the key. An electric priming fuel pump is the perfect choice over a mechanical pump because it will charge the fuel system within seconds and will avoid fuel starvation of the injection pump and engine. The reliability of these engines, however, requires occasional maintenance to the fuel filter and water separator. When this maintenance or filter change is performed, the fuel system is drained and requires air purging and fuel priming prior to attempting the startup. The electric fuel pump performs this job extremely well with the simple turn of the ignition key. The days of squeezing a priming ball until your hand falls off or pushing and pulling buttons or levers on a mechanical fuel pump primer are gone.

Time is money and the ability to get every piece of compact equipment up and running quickly, efficiently and at optimum performance, spells the difference between profit and loss on the jobsite. Today’s electronic fuel pump technology is meeting this challenge.

Paul Puleo is a national sales manager for Facet-Purolator Electronic Fuel Pumps at Motor Components LLC, based in Elmira Heights, N.Y.