How to Install an Aftermarket Diesel Fuel Pump

  • 3-5 hours
  • Intermediate
  • 65-250
What You'll Need
New fuel pump
Socket wrench set
Locking ring tool

It might be that you’ve decided to add an aftermarket diesel fuel pump for greater efficiency or it could be that your old diesel fuel pump has failed and needs to be replaced. Installing a new fuel pump is a job that requires a little skill, but it’s one that most people can manage with some patience. As always, when working around fuel and electricity, be very careful.

Step 1 - Selecting the Fuel Pump

It’s important that you select a diesel fuel pump that’s right for your vehicle. Do your research to determine which models will fit. A great deal will depend on the size of your engine. If you’re not sure, ask at your auto parts store. The people there will be able to advise you and help you buy one that’s appropriate.

Step 2 - Preparation

Before you can begin work on the diesel fuel pump, you need to prepare the engine. Do this by relieving the pressure on the fuel system, then removing the negative battery cable from the terminal.

At this point you’re ready to drain the fuel tank, which is a necessary step; don’t skip it. Drain it into a clean container, as you’ll be returning it to the fuel tank later. Do this by releasing the plug in the tank. Once it’s completely drained, use your wrench to disconnect the tank. Wear gloves to keep fuel from your hands at this step.

Step 3 - Removing the Old Pump

To take out the old diesel fuel pump, you need to take off the electrical connector before you use a wrench to carefully disconnect the fuel pump from the fuel line, then take off the fuel tank. You’ll see that the fuel pump is connected to the fuel line on the engine side by a lockspring connector. You’ll need a special tool to remove this before you can take out the fuel pump. Disconnect the fuel pump and throw away the old O ring.

Step 4 - New Pump

Unpack the new diesel fuel pump. It should come with all you need to install it, including the new O ring. Tighten the locking ring back on using the locking ring tool. Put the fuel pump back on the vehicle and then secure the diesel fuel pump to the fuel line.

The electrical connector needs to be hooked up to the fuel pump at this point. Now, you should reconnect the fuel tank. At this point you can put the diesel fuel back in the tank, although you need to be certain that the drain plug is closed first. Once you completed that, put the negative battery cable back on the cable and tighten. With everything back in place, you’re ready to start the engine and check that everything is working properly.