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How to Replace a Fuel Pump

Omkar Phatak
If you are looking for guidelines on replacing a fuel pump in your car, this story will help you out. Read to get a quick overview.
A fuel pump is one of the most important devices in a car, as it is responsible for the injection of fuel, inside the engine. The engine forms the heart of a car and it needs a continuous supply of fuel, at the right pressure, for smooth functioning.
Modern cars have electric pumps. In case, the pump is not performing to its full capacity and is supplying an insufficient volume of fuel, at inadequate pressure, it needs to be replaced.
The replacement is essential, as a problem with this component, can drastically bring down the efficiency of your car's engine. It is important that an accurate diagnosis is made, before you proceed.
Therefore, before replacing the pump, be absolutely sure that it is indeed the source of the fuel injection problems and is beyond repair. Make sure that other components like the fuel filter, fuel pressure regulator, or a clogged fuel line is not the culprit.
Only after all these possibilities are eliminated and you are dead sure that the pump is the culprit, then go for a replacement.

Replacement Procedure

Replacing the pump is a job that needs to be handled very carefully, as you will be dealing with inflammable material. Make sure that you work in an area that is well ventilated and have a fire extinguisher close by. The tools that you will need for replacing the pump are the following
  • Container For Storing Fuel
  • Flat-head Screwdriver
  • Phillips Head Screwdriver
  • Wrench Set
  • Socket Set
  • New Fuel Lines
  • New Pump of the Same Model
Make sure that you buy a pump that is exactly same as the old one. The cost will depend on the car model. Firstly, disconnect the negative terminal of the battery, to avoid any mishaps due to sparking.
The pump creates high pressure to push fuel, that is contained in the tank, into the injection system. Even after the engine is shut off, the fuel pressure stays sustained. That is why, before you start replacing, you need to release the pressure, as otherwise it may lead to an explosion.

Release Fuel Pressure

To release this pressure, you need to locate the relay or fuse, that is connected to the fuel pump. Start the car and keep it idling. Then pull out either the pump fuse or relay, which will make the engine die for the time being and also release all the locked pressure inside the fuel lines. Then, shut down the car and let it cool down for some time.

Access the Old Pump

Rest of the part is accessing the pump, removing, and replacing it. Electric pumps are generally mounted in two separate ways, in different car models. One type is mounted in the fuel tank itself and the other type is installed under a car, next to the tank.
Jack up your car and put it on jack stands firmly. Then, sliding underneath, you must locate the pump, placed in front of the gas tank. It can be identified by the fuel line which connects the tank to the pump. These pumps are covered in insulation sleeves, that need to be removed by unbolting.
In case your car has a pump which is installed inside the fuel tank, you will need to remove it from the tank. To do that, you will have to access the tank inside, through a hatch, that is normally located underneath the backseat, floor, or through the trunk floor.
To remove pumps in both cases, one has to disconnect all the other components and wires attached to them. For removing the pump from inside the tank, you will have to first drain the fuel out of the tank, using an appropriate apparatus.

Disconnect Fuel Lines and Wiring

In both cases, the fuel lines need to be disconnected first. For a pump that is installed inside a tank, after fuel has been drained, you will need to disconnect only a single line, which is connected at the top of the pump.
In the other case, there will be two lines connected with the pump, that will have to be disconnected. To disconnect these lines in both cases, you will first have to get the hose clamp, holding the lines loosened. After that, you will be able to remove the lines.
Ensure that the leaking fuel from the disconnected lines is collected in a container and does not spill around. The last part is removing the electrical connections made to the pump. There will be a ground wire and a main wire attached. Both need to be removed. Make sure that you remember the order of the wires, while reconnecting them to the new pump.

Removing and Replacing

Remove any bolts or brackets that hold the pump in place. With that, the pump can easily be removed. Replace it with the new pump and place it in the same position, as the old one. Replace the old fuel line, with the new ones, in both cases.
Make the electrical connections back again and go in exact reverse, to reconnect everything back again, as it was. Put the engine pump valve or relay back in place. Reconnect the car battery and your job is done.
However, make sure that you read the fuel pump replacement instructions for your car model (through a Hayne's manual) and follow them to the word. If you are doubtful about the procedure, it is best to leave the job to a professional.