Fuel pumps are designed to transfer fuel from the fuel tank to the engine fuel management system. Fuel pumps only create flow from the tank to the fuel rail. However, the size of the lines and restrictions cause the fuel to create pressure.
When the fuel pressure is low, the symptoms are that either a fuel pump if failing or a fuel filter is clogged up.
Most of the time fuel filters get plugged due to lack of maintenance. Most people don’t realize that the fuel filter needs replaced due to the mineral deposits drawn into the fuel tank when fueling at a gas station.
Most modern vehicles today have a fuel filter and fuel pump as one unit making it to where the fuel pump must be replaced to change the filter.
Changing a fuel pump can be tricky. On older vehicles, the fuel pump was located on the engine block and usually was relatively easy to access. On the vehicles today, the fuel pump is located in the fuel tank making it to where the fuel tank must be removed to switch out the fuel pump.
Dealing with fuel tanks can be a bit tricky. It is best that the fuel tank is on or near empty. A full tank of gas can weigh up to 94 pounds, not including the tank itself. A whole unit can range from 125 to 250 pounds, depending if the fuel tank is plastic or metal.
- Note: Fuel necks and vent hoses should be replaced when the fuel tank is removed.
When removing the fuel pump from the fuel tank, there is usually a float on the end of the pump. This can be tricky when removing. Just pull up on the pump and turn the pump to its side and the float will come out.
- Note: Do not let the float break off inside the fuel tank. The float can be suck up to the fuel pump intake port and cause the pump to overheat. Also, do not get any debris inside the fuel tank. This will contaminate the fuel and possibly cause the new fuel pump to prematurely fail.
If a fuel filter is located inline between the fuel pump and the fuel rail on the engine, it is recommended to replace the prior to the pump is installed. This will aid in collecting any debris from the pump as it is new and may have small particles from the manufacture. Plus, the old filter may be plugged up causing a strain on the new fuel pump making it overheat and prematurely fail.
After replacing a fuel pump and fuel filter, it is highly recommended to fuel up at a gas station with good gas, such as Techron or Chevron. This fuel is very clean and has detergents that help clean the fuel system. Along with getting a good fuel, it is also good to drive the vehicle on a road trip to burn all the fuel in the tank resulting in flushing out all the old gas, which may be watered down.
If your fuel pump needs to be replaced, book one of our automotive specialists at YourMechanic for an easy and convenient service experience.
This article originally appeared on YourMechanic.com as Why Fuel Pump Replacements Can Be Tricky and was authored by Marvin Sunderland.