Installing A Fuel Pressure Gauge: A Supra Guide

Installing a fuel pressure gauge on a Supra is a complex process that requires careful planning and execution. It involves working with the fuel system, which can be dangerous if not done properly. There are two main options for buying the fuel system: a pre-assembled fuel kit from a vendor or buying all the parts separately. The pre-assembled kit has benefits such as pre-assembled lines and exact fittings, but it is more expensive. Buying the parts separately can save money, but it requires more research and planning.

The process involves removing and modifying various parts of the car, including the throttle body, oil dipstick guide, air intake chamber, electrical connectors, fuel lines, and more. It is important to mark and label all the parts and their connections before removal to make re-assembly easier.

One of the critical steps is tapping into the fuel line to install the fuel pressure sensor. This step requires knowledge of the fuel system and attention to safety, as working with pressurised fuel lines can be hazardous.

Overall, installing a fuel pressure gauge on a Supra is a challenging task that requires mechanical knowledge, careful planning, and attention to safety. It is important to follow instructions and seek advice from experienced individuals or professionals when attempting this modification.

Tapping into the feed line

Firstly, it is important to gather the necessary tools and materials. You will need items such as a fuel pressure sensor, a T-connection, fuel injection clamps, a drill, and appropriate fittings and hoses. Ensure you have personal protective equipment, such as gloves and eye protection.

Next, locate the feed line. This is usually the OEM feed line, which is the same size as a -6 AN line. Before making any connections, it is crucial to relieve the pressure in the fuel line to avoid any accidents. Refer to your vehicle's manual to locate the fuel pump fuse and follow the recommended procedure to relieve the pressure.

Now, you can proceed to tap into the feed line. Cut the fuel line and insert a T-connection, ensuring a tight and secure fit. This T-connection will serve as the mounting point for your fuel pressure sensor. Secure the sensor in place with fuel injection clamps, being careful not to overtighten them, as this can damage the fuel line.

At this stage, you should also drill any necessary holes for mounting the sensor and its associated components. Use the correct drill bit size to avoid damaging the thin and cast material around the fuel line. Clean the area thoroughly to remove any debris generated during the drilling process.

Finally, connect the fuel pressure sensor according to the manufacturer's instructions. Ensure all connections are secure and tight to prevent leaks. Double-check your work and test the system to ensure there are no leaks.

Remember, this is a complex task, and it is important to have the necessary skills and knowledge before attempting it. If you are unsure about any steps, seek advice from a professional mechanic or a trusted forum for Supra enthusiasts. Safety should always be your top priority when working on your vehicle.

Removing the stock regulator

To remove the stock regulator, start by removing the fuel rail and unbolting the stock FPR. Next, tap the FPR hole with a 1/4" pipe tap, making sure to clean it thoroughly afterward. Insert a -6AN male fitting with a 1/4" male NPT, then re-install the fuel rail and assemble the intake components.

Now, measure the required length of fuel line and connect the compression fittings. Connect the stainless steel line to the fuel rail and the FPR. Remove the fuel return line from the hard line underneath the intake manifold and connect it to the barbed fitting attached to the "OUT" of the FPR. Finally, mount the FPR and set the stack pressure to 37-40 psi.

Installing a new regulator

Installing a new fuel pressure regulator is a complex process that requires careful attention to detail and a good understanding of car engines. Here is a step-by-step guide on how to install a new fuel pressure regulator on a Toyota Supra, which has a fuel regulator located between the fuel rail and the fuel injectors.

First, ensure the car is parked on level ground and turn off the ignition. Disconnect the negative battery terminal using a wrench to remove the negative cable from the battery. Locate the fuel pressure regulator on the engine, typically found between the fuel rail and fuel injectors. Disconnect the electrical connector from the fuel pressure regulator. Loosen the clamps holding the fuel lines with a wrench and remove them from the regulator. Unscrew the mounting bolts of the fuel pressure regulator from the engine using a wrench.

Now, you can install the new fuel pressure regulator. Secure the mounting bolts and reconnect the fuel lines and electrical connector. Tighten all connections.

Turn on the ignition to check that the new fuel pressure regulator is functioning correctly. If it is, turn off the ignition and reconnect the negative battery terminal, tightening the connection with a wrench.

Some additional tips for this process include soldering connections where possible, and if wire connectors are used, ensure proper connections are being made. Take your time and pay attention to detail to ensure a safe and effective installation.

There are also some specific approaches to installing an adjustable fuel pressure regulator. For example, one approach is to remove the stock regulator and install a fitting into the rail, then connect braided hoses to the unit. Another approach is to keep the stock system and run a hose from the fuel rail to the new regulator, allowing for a quick switch back to the stock system if needed.

Wiring the fuel pumps

The following section will guide you through the process of wiring the fuel pumps for your fuel pressure gauge installation on a Supra. It is important to follow safety precautions and refer to a professional mechanic if you are unsure about any steps.

Firstly, it is important to understand the wiring diagram provided in the source material. This diagram illustrates the preferred method for wiring the fuel pumps, ensuring their proper and safe function. The diagram shows that each fuel pump is powered by a relay, which is activated when the vehicle is turned on. The relays are connected directly to the battery for a constant 12v power source. Additionally, a switched source is obtained for the relays, providing power to the pumps only when the vehicle is on. This safety feature prevents the pumps from continuing to operate in the event of an accident.

Now, let's begin the wiring process:

• Start by preparing the 12v constant connections at the battery end and work your way back.
• Test run the wires into the vehicle through the grommet behind the wheel well.
• Tidy up the wiring by using zip ties or line holding brackets to secure the wires along the base of the car and into the trunk area.
• Connect the 12v constant wires to the relays (blue relay wires) in the trunk area.
• Extend the 12v switched wires (white relay wires) and the accessory (pump) power wires (yellow relay wires) to the relays.
• If you have opted for warning lights, now is the time to wire them into the accessory feed.
• Route the pump wires through the OEM grommet and underneath the car/tank to the pump hanger area.
• Prepare the OEM power/ground wire by soldering a power wire to either the blue or white OEM wire and covering it appropriately.
• Route the hanger ground wire back out using the same path as the power lines to ensure a tight seal on the cover.
• Connect the 12v switched power source to the Fuel ECU. Ensure your vehicle does not have the 12v Fuel Pump Mod. If it does, revert it to stock settings. Splice the 12v switched power source for each relay at this point.
• Mount the relays and wire the ground connections. Cover up the wiring for a clean finish if desired.

By following these steps and referring to the wiring diagram, you will have successfully wired the fuel pumps for your fuel pressure gauge installation on your Supra. Remember to take your time, pay attention to details, and ensure all connections are secure and properly insulated.

Mounting the fuel pressure gauge

To mount the fuel pressure gauge, you will need to decide on a suitable location for it. Some people choose to mount it directly on the rail, while others prefer to mount it remotely.

Once you have chosen a location, you will need to gather the necessary tools and materials. These include a drill, a 1/4" pipe tap, a wrench, and the appropriate fittings and hoses.

If you are mounting the gauge directly to the rail, you will need to remove the fuel rail and unbolt the stock FPR. Tap the FPR hole with a 1/4" pipe tap, being careful not to crack the thin cast material. Clean the hole, making sure it is free of any debris. Insert a -6AN male fitting with a 1/4" male NPT. Reinstall the fuel rail and assemble the intake components.

If you are mounting the gauge remotely, you will need to measure and cut the necessary fuel lines. Connect the compression fittings and attach the SS line to the fuel rail and FPR. Remove the fuel return line from the hard line underneath the intake manifold and connect it to the barbed fitting on the "OUT" of the FPR.

Finally, set your desired fuel pressure, typically between 37-45 psi for a stock fuel system.

Frequently asked questions