How to Replace a Fuel Pressure Regulator

What You'll Need
Torx screwdriver
Compressed air
Cleaning solvent

Replacing a fuel pressure regulator can be a difficult task for a novice DIYer, but if you know your way around an engine, you can save yourself more than a thousand dollars by replacing the regulator yourself. This project will take several hours to complete, so make sure you have the time to complete it. Since vehicle engines vary greatly, this guide may not apply to your vehicle, but it should help you with a general guideline of how to complete the replacement.

Step 1- Get to the Regulator

You will need to first relieve the pressure in the fuel system. You can accomplish this by removing the fuel cap, and fuel pump relay. Then start the car and it will run for just a short time before stalling. Now you need to clear a path so that you can access your fuel pressure regulator. This is the part that will vary most among different vehicle models. Your regulator may be easier to reach, or more difficult. Remove your main harness electrical controls and then remove the harness itself. Disconnect the engine coolant temperature electrical connector, along with the barometric pressure sensor electrical connector. Disconnect the glow plugs and fuel rail temperature sensor connector. Now remove the left fuel injector electrical connectors followed by the fuel pressure regulator connector. Remove the oil level sensor harness and the PCV hose. Remove the injection pump inlet hose and move out of the way.

Step 2- Clean the Area

Before you remove the fuel pressure regulator, you need to clean the entire area with solvent. Check your vehicle's manual for recommended solvents for your vehicle. Make sure that you clean the regulator itself, any connectors, the high pressure injection pump, and any lines coming to or from the regulator. After you clean everything with the solvent, you should use compressed air to completely dry the area.

Step 3- Remove the Regulator

Now that everything is clean, you need to remove the regulator. Your regulator may be held on by regular bolts, or it may use TORX screws. There are typically either three or four bolts or screws that attach the regulator. Once you have removed the bolts or screws, you are ready to install the new regulator. If at this point you find any debris on the fuel injection pump seat, you will need to correct this before proceeding. First, take a clean rag and place over the pump bore to soak up the excess fuel. Then bump the engine over to flush any additional debris from the regulator bore.

Step 4- Install the New Regulator

You will need to install new O-rings along with your new fuel pressure regulator. You need to lubricate the O-rings with new engine oil, and then install them. Now you can install your new fuel pressure regulator by replacing the screws or bolts. Then follow these directions in reverse, replacing the hoses, lines, connectors, and main harness. Once everything is back together, re-pressurize the fuel system by turning the ignition switch on and back off again several times.