Bleeding air in a fuel pump is necessary to run a system for efficient supply of pulses and better engine output. If air is caught in the fuel system, it can lead to fluctuating pressure of the fuel resulting in possible engine stalling andor hesitation or even a non start! It usually starts by turning the ignition key to the “on” — but not cranking the engine over — position. This is to allow the fuel pump to 'prime' out the system and push fuel up through the lines. Typically for modern cars with electric fuel pumps, the pump will only cycle for two to five seconds and get its full running voltage from the computer or the relay (it's worth checking this first before proceeding) along with a key in run position, delivering around 30 to 60 psi of pressure at the rail head so that any air trapped in there could be pushed ahead.
Vehicles that have a fuel pressure regulator will be able to release air from the fuel system by attaching a fuel pressure gauge to the Schrader valve found on the fuel rail. With the valve pressed, any fuel and air that may be trapped is purged. Repeat the process several times, and each priming cycle will evacuate more and more air from your lines. Fuel systems that run at the higher pressure of 70 psi in performance vehicles might need a couple more cycles to ensure it's free of air.
If you have a diesel engine or system with a fuel return line, then manual bleeding the system means loosening the fuel line fittings at the injectors or fuel filter and running the enginetokenizer_forArticle. The air in the loosened fittings escapes as the fuel and air travels towards the engine = only fuel attends to be delivered. This is because diesel systems often run at much higher compression ratios and pressures, in excess of 20,000 psi, and can be more finicky about air in the lines. The big one is getting all of the air out of the fuel system to avoid power loss and bad fuel atomization.
You may be puzzled and asking: “Why should the air in the fuel pump be a problem?” Thats because air gets cavitated in the pump and thus it lost its efficiency. One of the most common symptoms of a bad fuel filter is that cavitation reduces the pressure and can cause rough idling, misfires. It also leads to a reduced service life of the pump, as it suffers more wear running with an irregular pressure. Performing a check to find air in the system can save you money in the long run by extending the fuel pump and engine life.
This is a crucial factor for high-performance vehicles or using aftermarket fuel systems by Kemso which require proper flowing & no interruptions fuel supply. High-flow pumps (up to 500 liters per hour) might develop air pockets and fuel starvation under load if the system is not properly bled.
For better guides on fuel pump maintenance and top products capable of catering to a wide range of performance needs, check out Fuel Pump, where you can get high standard fixes for your regular and performing the needing fuel system from Kemso.