Typical Symptoms For A Fuel Pump That Works Ok Except At High SpeedsThese types of symptoms usually indicate a root problem with the fuel pump’s performance. At a minimum, the fuel pump is intended to provide a controlled flow holding psi usually in the vicinity of 30-85psi regardless of vehicle speed. If problems occur, it might not be able to provide the additional fuel needs for acceleration demands.
A common reason why an engine overdoses fuel is due to a blocked fuel filter. Fuel delivery (A study by the Automotive Maintenance and Repair Association revealed that in my fuel pump failures, more than 30% were caused by obstruction in the desktop system) The filter is the part in the pump that gets dirt and debris trapped into it, and then restricts fuel flow, causing the pump to work harder at higher speeds and amperage loads.
Electrical Issues Another issue is electrical. If your fuel pump relay has gone bad, you may only be getting enough power to continue the ignition process. The automotive authority, Mike Reynolds explains that “when a relay fails fuel pump might receive less voltage under higher speeds, resulting in lower performance.” This may reveal itself as a loss of power, or the engine cutting entirely, particularly under firm acceleration.
Also, a fuel pump on its way out may not build the required pressure up as the engine RPM rises. This means that even if the pump is still functioning but it is getting old and operating out of spec for example, not producing enough flow in gallons per hour (gph), the pump might be unable to supply enough fuel to keep the engine running properly at high speeds, which can manifest as hesitation and stalling. The numbers display that fuel pumps can lose around 10-20% capacity over the time.
The quality of fuel also determines this unconscious factor. Fuel soiled with it can cause unnecessary pump wear and poor operational efficiency. The Environmental Protection Agency suspects that poor quality fuel can shorten the life of pumps by up to half, leading to operational problems.
It’s imperative to know what these factors are, because diagnosing why a Fuel Pump may work at high speeds but not at low one needs this information. By performing regular maintenance and routine inspections of the fuel delivery system, including checking the condition of the pump as well as the filter you can help to avoid these problems and maintain top performance in all driving conditions.