Fuel Pressure Regulator: Saturn Sky's Performance Enhancer?

The Saturn Sky does have a fuel pressure regulator. The fuel pressure regulator is located on the driver's rear wheel area, just outside of the gas tank. It is a Fuel Pressure Regulator (FPR) and filter all-in-one unit. The FPR controls fuel pressure by maintaining a pressure balance across the regulator. The fuel system pressure remains constant and is not influenced by engine load or a vacuum signal. This allows the system to be returnless, with fuel returning only from the filter/regulator in the engine compartment.

Symptoms of a failing fuel pressure regulator

The Saturn Sky does have a fuel pressure regulator.

A failing fuel pressure regulator can cause a range of issues with your vehicle, including:

• Engine performance problems: You may experience hard-starting, rough running, stalling, and a lack of power. The engine may run rich (too much fuel) or lean (too little fuel), leading to poor performance.
• Check Engine Light: The check engine light will likely illuminate as the engine computer detects issues caused by a faulty regulator, such as irregular fuel levels.
• Dark smoke from the exhaust: A malfunctioning regulator can upset the engine, resulting in dark plumes of smoke from the exhaust.
• Fuel in the regulator's vacuum line: A ruptured diaphragm inside the regulator can cause fuel to leak into the vacuum line.
• Vehicle crank but won't start: A faulty regulator can prevent the engine from receiving proper fuel pressure, resulting in a vehicle that cranks but refuses to start.

It is important to address these issues promptly to avoid further complications and ensure the safe and efficient operation of your vehicle.

Benefits of an adjustable fuel pressure regulator

The Saturn Sky does have a fuel pressure regulator.

An adjustable fuel pressure regulator can help you get more power out of your engine, although this is usually only the case when coupled with other engine modifications or changes. The regulator works by controlling the pressure of the fuel supplied to the injectors on an engine, and an adjustable regulator allows the user to set the base pressure to match the injectors and fuel pump system. This can be particularly useful for high-horsepower cars, as a high-flowing regulator is critical to ensuring that the fuel pressure differential between the inlet and outlet of the injector is optimal.

Additionally, an adjustable regulator can be beneficial for cars with high-pressure fuel pumps, helping to prevent fuel surging or starvation. It can also be useful if you are using a specific type of fuel, such as race fuel or alcohol, as these fuels may require a higher-series regulator.

However, it's important to note that an adjustable fuel pressure regulator alone may not provide significant benefits. Other modifications, such as changes to the injectors or a tune-up, are often necessary to see noticeable improvements in performance.

Fuel pressure regulator location

The fuel pressure regulator in a Saturn Sky is located under the driver's rear wheel area, just outside of the gas tank. It is a fuel pressure regulator and filter all in one unit.

The location of a fuel pressure regulator is important and can affect its performance. Some people may choose to mount the regulator in a convenient and easily accessible space, while others may opt for a location that is out of the way to achieve a "cleaner look". However, placing the regulator closer to its destination (fuel rail, fuel log, carburetor, diesel or direct injection pump) can improve fuel pressure regulation. The longer the fuel line between the regulator and its destination, the greater the potential for fuel pressure loss.

In older vehicles with continuous return fuel systems, the fuel pressure regulator is typically mounted in the fuel rail and controlled by engine vacuum. On the other hand, most modern vehicles use a return-less fuel system, where the fuel pressure regulator is usually built into the fuel pump assembly, allowing for more precise fuel control and reduced emissions.

Fuel pressure regulator replacement cost

The fuel pressure regulator in a Saturn Sky is located under the driver's rear wheel area, just outside of the gas tank.

The cost of replacing a fuel pressure regulator varies depending on the vehicle and the provider. The average cost for a fuel pressure regulator replacement is between $275 and $333, with labour costs estimated between $103 and $130, and parts priced between $172 and $203.

Some providers offer a fixed price for specific car models. For example, the average cost for a fuel pressure regulator replacement for a Saturn Vue is $224.

For other car models, the cost of replacement can be significantly higher. For instance, one user reported being quoted $425-$475 to replace the fuel system regulator of their 1992 4Runner. Another user was quoted $525 to replace the regulator of their 6.7 Powerstroke, while their mechanic estimated the cost to be between $650 and $800.

It is worth noting that replacing a fuel pressure regulator is a complex task that involves disconnecting the battery and discharging the fuel pressure from the fuel system. Therefore, it is recommended to seek professional assistance or an experienced mechanic for the replacement.

Diagnostic procedure instructions

The following diagnostic procedure instructions are for a 2007 Saturn Sky with a DTC (Diagnostic Trouble Code) of P0090, P0091, or P0092. These codes indicate an issue with the fuel pressure regulator or the fuel pressure regulator solenoid control circuit. Before beginning the diagnostic procedure, it is important to perform the Diagnostic System Check - Vehicle and review the Strategy-Based Diagnosis for an overview of the diagnostic approach.

To begin, verify the conditions for running the DTC. The ignition 1 signal parameter should be between 6-18.1 volts, and the DTCs will run continuously within this enabling condition. Next, check the conditions for setting the DTC. The high-pressure fuel pump actuator voltage should be between 1-4.5 volts with the actuator commanded off for more than 4 seconds. Additionally, the high-pressure fuel pump actuator voltage should be less than 1 volt with the actuator commanded off for more than 4 seconds, or more than 4.5 volts with the actuator commanded on for more than 4 seconds.

Once the conditions for setting the DTC have been confirmed, the next step is to take action based on the specific DTC. For DTCs P0090, P0091, and P0092, a message center or indicator will display "Reduced Engine Power." To clear these DTCs, refer to the reference information provided in the service manual.

Now, perform circuit/system testing to identify the root cause of the issue. Start by verifying that a test lamp flashes between the high-pressure fuel pump actuator low-control circuit terminal 1 and B+. If the test lamp is always on, test the low-control circuit for a short to ground, and if necessary, replace the ECM. If the lamp is always off, test the same circuit for a short to voltage or an open/high resistance, and replace the ECM if needed. Next, with the ignition on, verify that a test lamp illuminates between the high-pressure fuel pump actuator high-control circuit terminal 2 and ground. If the lamp does not illuminate, test the circuit for a short to ground or an open/high resistance, and replace the ECM if the circuit tests normal.

If all circuits test normal, the issue may lie with the high-pressure fuel pump. To further diagnose this, perform the following tests:

• Ignition off, disconnect the harness connector at the high-pressure fuel pump.
• Test for 0.49 ohms plus/minus 0.023 ohms at 20°C (68°F) of resistance between the low-control circuit terminal 1 and FRP regulator high-circuit terminal 2. If the resistance is not within the specified range, replace the high-pressure fuel pump.
• Test for infinite resistance between each terminal and the high-pressure fuel pump housing/case. If the resistance is not within the specified value, replace the high-pressure fuel pump.
• With the engine idling, command the Fuel Pressure Control to Increase with a scan tool. The Actual Fuel Rail Pressure should increase with each command. If it does not, replace the high-pressure fuel pump.

After completing the diagnostic procedure, perform the Diagnostic Repair Verification to ensure the issue has been resolved. Refer to the provided Control Module References for ECM replacement, setup, and programming, as well as High-Pressure Fuel Pump Replacement if necessary.

Frequently asked questions