How To Replace Mustang Fuel Pump | 1986-97

In this article, LMR shows you how to remove and replace the fuel pump covering all 1986-1997 Mustang applications. Whether you walk out to your ride and experience a no-start condition or are prepping your fuel system for an upgrade, installing a fuel pump is a common service part that is needed for all Mustangs. Dropping in a new pump is an easy task to accomplish.

Follow along, and we will show you the step-by-step instructions to knock this one out. Overall this one should take you roughly 1-2 hours to complete.

Tools Needed

• lift or jacks & jack stands
• socket set
• hammer
• assorted screwdrivers
• wire strippers
• wire crimp tool
• needle-nosed pliers
• fuel disconnect tools
• heat gun or torch

86-97 Mustang Fuel Pump Removal Steps

1. Start by removing the fuel tank from the vehicle. If you need to know how to complete this task check out our 83-97 Mustang fuel tank removal article.


2. Once you have the tank out, take this to a clean work surface. Remove the plastic retaining clip holding the main 5/16" supply line with a small flat-bladed screwdriver.


3. Next, using a fuel line disconnect tool, remove the 1/4" return line.


4. Disconnect the electrical connector.


5. Using a flat-bladed screwdriver or a punch, tap the lock ring out of place. Once this is off, you can remove the fuel pump bracket from the tank.

86-97 Mustang 155LPH or Stock Fuel Pump Installation & Wiring Steps

We will be installing a new fuel pump hanger bracket on our application at this time. These same steps can be used if you will be reusing the factory bracket.

1. First, remove both of the pump bracket screws.


2. Take both of the red protective caps off of the pump inlet and outlet.


3. Install the rubber isolator and then you can test fit the pump into the bracket.


4. Next, test measure your S-hose and trim accordingly. Make sure there are no kinks or bends and that it will allow the fluid to flow adequately.


5. Place your clamps on your S-hose and slide the hose onto the pump side first.


6. Now you can fully tighten the clamp on the pump side.


7. Place the pump back in the hanger and then slide the S-hose back onto the bracket side and fully tighten the clamp.


8. Reinstall both of the bracket screws.


9. Press on the fuel filter sock at this time.


10. Using a pair of needle-nosed pliers, attach each of the electrical terminals. You can see the differences here in the terminals’ size, but the pump is also clearly marked with a plus for positive and a minus for negative.


11. Once this is connected, you are all done and can reinstall the assembly back in the tank.

86-97 Mustang 255LPH Fuel Pump Wiring Steps

Moving over to the larger 255 liters per hour style pump, you can see the apparent size difference and the differences between the electrical connectors. All of the general installation steps will be the same other than the electrical portion.

1. Now we can test the length of the wiring. Set each end of the factory wiring next to the supplied connector. Snip each of the wires at this time.


2. Strip each end of the wire and twist them to sit in the provided butt connector to sit flush. You can cut off any excess wire if you stripped off too much.


3. Using a crimp tool, attach one side of the butt connector and secure it to the wire. Do the same for the other wire.


4. Moving to the supplied connector we cut, strip these wires as well. This next step is not necessary, but we used a couple of small sections of heat shrink to make the connections look better and provide extra strength to the connection once completed.


5. Slide the heat shrink over the wire, then crimp the other side of the butt connector to the wire.


6. Slide the heat shrink over the butt connector and, using a heat gun, apply heat until it shrinks up to the wiring. Be sure to do this for both wires.


7. Plug in the connector to the pump, and then you can set this back in the housing.


8. With the assembly fully tightened down, press on the fuel filter sock at this time.


9. Once this is connected, you are all done and can reinstall the assembly back in the tank.


10. Fold the sock assembly into the opening on the tank and slide the bracket back in the tank at this time.


11. You can use the filler neck hole on the side of the tank to help you align the pump with the internal baffle on the inside of the tank.


12. Slide the new O-ring back on, and then the lock ring. Fully seat the lock ring at this time.


13. Check over your work, and now you are all done!

We hope that this article has helped you and you have a better understanding of how to replace your fuel pump in your 86-97 Mustang.