Replacing the fuel pressure regulator

If you have throttle-body fuel injection, you don't have a fuel rail. The fuel pressure regulator should be mounted to throttle body.

Be sure to release the fuel pressure prior to removing the Pressure Regulator.
Fuel Pressure Regulator is under this clamp.

You should have a test port on the Fuel Supply rail, use a tool from a local auto parts "Tool Loaner program" where you can borrow tools for free,w/a deposit of course,then follow the steps provided;

MPI Fuel System Pressure Test

The MPI fuel system used in vehicles equipped with a 4.OL engine employs a vacuum balanced pressure regulator. Fuel pressure should be approximately 55-69 kPa (8-10 psi) lower with the vacuum line attached to the regulator than with the vacuum line disconnected. System fuel should be 214 kPa (31 psi) with the vacuum line connected to the regulator and 269 kPa (39 psi) with the vacuum line disconnected. CAUTION: Some fuel may be discharged when connecting fuel gauge to fuel rail.

1. Connect a 0-414 kPa (0-60 psi) fuel pressure gauge to test port pressure fitting on fuel rail (Fig. 7).
2. Remove vacuum line from pressure regulator.
3. Start the vehicle.
4. Note gauge reading. With vacuum line disconnected, fuel pressure should be approximately 269 kPa (39 psi).
5. Connect vacuum line to pressure regulator. Note gauge reading. Fuel pressure should be approximately 214 kPa (31 psi).
6. If fuel pressure is not approximately 55-69 kPa (8-10 psi) higher with vacuum line removed from regulator, inspect pressure regulator vacuum line for leaks, kinks or blockage. CAUTION: Fuel pressure will rise to as much as 655 kPa (95 psi) when the fuel return tine is pinched shut, shut engine down immediately after pinching oft fuel return line.
7. If fuel pressure is low, momentarily pinch shut the hose section of the fuel return line. If fuel pressure remains low, inspect the fuel supply line, fuel filter, and fuel rail inlet for blockage. If fuel pressure rises replace fuel pressure regulator.
8. If fuel pressure is above specifications, inspect the fuel return line for kinks and blockage.

Capacity Test

1. Remove the cap from the pressure test port in the fuel rail.
2. Connect a 0-414 kPa (0-60 psi) fuel pressure gauge to the pressure fitting on the fuel rail (Fig. 7).
3. Start the vehicle. Pressure should be approxi- mately 214 kPa (31 psi) with the vacuum hose connected to the pressure regulator and 269 kPa (39 psi) with the vacuum hose removed from the pressure regulator.
4. If the pressure is not to specification, check the following before replacing the fuel pressure regulator:

• 4a - Inspect the fuel supply and return lines/hoses for kinks or restricting bends
• 4b - Check the fuel pump flow rate. A good fuel pump will deliver at least 1 liter of fuel per minute with the fuel return line pinched off. If the fuel pump does not pump adequately, then inspect the fuel system for a plugged fuel filter or fuel pump inlet filter (sock). Fuel pump flow rate can be done by connecting one end of an old A/C gauge hose to the fuel test port on the fuel rail and inserting the other end of the hose into a container of at least 1 liter capacity. Run the fuel pump by installing a jumper wire into diagnostic connector terminals D1-5 and D1-6. Be sure to pinch off the fuel return line or most of the fuel will be returned to the fuel tank.

You will need a torx bit, either a t35 or a t40 I believe. You will also need a 1" or a 1 1/16" The pressure regulator can be removed without removing the throttle body but you would need to have some experience replacing them to figure it out. First remove the throttle body from the intake plenum. Using the 1 inch wrench loosen the nut that holds the fuel line to the lower part of the fuel pressure emulator. Use the torx bit to remove the bolt that holds the regulator to the fuel rail. Place a rag around the regulator to catch and fuel that may spray and pull the reegulator out of the fuel rail then pull up on the regulator to remove to from the fuel line. If you have a 3.8 Liter than all you will need is a snap ring plier. Remove the plastic cover from the top of the engine, remove the snap ring that holds the regulator in place. Pull out the regulator. Be prepared for fuel to spray or spill. Make sure all the parts come out with the old regulator. Compare the old and new one to make sure they look identical. The screen and small oreng like to stick in the fuel rail. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Check the fuel pressure regulator. On the 3.1 liter it's in the middle of the engine between rails. On the 3.4 it's at the end of the rail. pull the vacuum hose off, plug the hose with a golf tee, start the car, and see if gas comes out of the vacuum port on the regulator. If yes, replace regulator. If no, check fuel pressure at schrader valve on rail. Pressure should be 41-47 psi. If higher, replace regulator. Let me know if you have questions.

3.1 liter:


3.4 liter

the fuel pressure regulator is on the fuel injector rail. it is where the fuel line for input connects to

The only thing left in this system is the fuel pressure regulator. You need to check pressure before the regulator and after the regulator if there is the problem then you need to replace it. I hope this helps. Don't forget to rate my answer.

replace your MAP sensor(manifold absolute pressure) the map sensor is the computer for your fuel pressure regulator telling how much pressure. Unless your tahoe runs like **** going up hill than it inevitably your fuel pump

Fuel pressure should be around 40-44 PSI at idle, if u replace the pump the correct pump has preset pressure, if the pressure is to high then the regulator may be stuck, it is near the injectors on the fuel supplu rail.

fuel pressure regulator? This diverts excess pressure from the rail back to the tank. When they wear out they usually stay stuck open thus diverting all pressure back to the tank. Pressure tests do not reveal this as pressure is checked before the rail not in it. I do believe you have a bad fuel regulator. They are 75US ouch.