How To: Submersible In-tank Fuel Pump Replacement

01
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What Kind of Fuel Pump Does My Car Have?

man looking under hood of car
Tuan Tran/Moment/Getty Images

So you've determined that you need to replace your fuel pump. You may have low fuel pressure, no fuel pressure, slow fuel flow -- any number of symptoms may have led you to the conclusion that your fuel pump is bad and needs to be replaced. The first question you need to answer is what type of fuel pump your car has. There are two types of common fuel pump: In-tank, or submersible fuel pumps, and external fuel pumps. The in-tank pump is installed on the inside of your fuel tank. Replacing it might sound like the kind of nightmare you'll need a can opener for, but it's pretty easy (more on that later).

The second type of fuel pump you may have is an externally mounted pump. These are mounted somewhere near the fuel tank on the underside of the vehicle. They are usually encased in a protective rigid foam or plastic material, then held on with a bracket. You will also see wires and fuel lines connected to this silver, cylindrical pump.

*Note: The best way to determine what type of fuel pump your car or truck has is to consult your car's repair manual. If you don't have a proper repair manual for your vehicle, now's the time to get one. You'll save hours of time.

If you've determined that your car has an externally mounted fuel pump, you need to check out this detailed tutorial on How To Replace an External Fuel Pump.

If you have an in-tank fuel pump, read on and we'll walk you through the basics of how to get it done, along with offering some safety tips to keep you out of trouble.

*IMPORTANT: Before you begin the job of replacing your in-tank pump, you need to drain the fuel tank. Trying to do this with fuel in the tank can be dangerous and isn't a good idea!

02
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Accessing Your Fuel Pump

Fuel pump access cover removed.
Back seat removed, you can see the access cover which hides the fuel pump access. photo by Matt Wright, 2011

*Drain the fuel tank before you begin this process. Safety First! On fuel injected vehicles (99% of what's on the road today) you need to depressurize the fuel system before you work on it. If you don't, you'll get fuel sprayed at very high pressure, all over the place, and with enough mist to cause a flash fire. If you don't know how to relieve the pressure in your system, read this.

Before you can remove the old, broken fuel pump, you need to access it. Most in-tank fuel pumps are installed from the top of the fuel tank. The good news is you can easily access this part of the tank by removing the bottom of the back seat. This can usually be done with the removing of a couple of bolts. Once the back seat is removed, you'll usually see what is clearly an access panel held in by some screws or bolts. Once removed you can see the top of the fuel tank, along with the top of the mount that holds the fuel pump, and in many cars also the wiring for the fuel level sending unit.

03
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Removing the Fuel Pump

Tap it counterclockwise to remove the pump.
Removal of an in-tank fuel sender and fuel pump. photo by Matt Wright 2011

With the access cover removed, and the tank drained (don't skip this step!), you can now disconnect and remove the fuel pump from the tank. There will be wiring entering through this pump housing, and the fuel line may be here, too. If you don't see the fuel line at this point, it exits at the bottom of the tank. Unplug the wiring harness, then if your pump has a fuel line at the top, go ahead and remove that. With the wiring and hose removed, you can remove the actual pump and pump housing. Some pumps are held in place with a few screws or bolts at the top. The one pictured above was locked in with a twist. To remove this type, simply tap the raised tabs with a drift or screwdriver in a counterclockwise direction. You only need to move it about 1/8 of a turn before it should pop out. Don't be afraid to give it some pretty good taps. If it's been in there for a while, that seal will be pretty stuck.

If you already removed the fuel line from the top of your pump, you can now lift the pump housing and pump directly out of the tank. It should slide right out. If your pressurized fuel exits from of the bottom of the tank, there will be a fuel line visible once you pull the pump out. In other words, the pump will come out of the tank, but still, can be attached like an umbilical cord to the inside of the tank. You can now disconnect that line and remove the pump.

Like most things automotive, installation is the reverse of removal. Be sure to use the new seal that came with your new fuel pump; you don't want any leaks!