Replacing Fuel Lines On A 3000Gt Vr4: A Step-By-Step Guide

Replacing the fuel lines on a 3000GT VR4 can be a challenging task, but with the right tools and knowledge, it is certainly achievable. The fuel lines are responsible for delivering fuel from the tank to the engine, and over time, they can become clogged or degraded, leading to poor engine performance and fuel efficiency. The process of replacing the fuel lines involves disconnecting and removing the old lines and installing new ones, ensuring all connections are secure to prevent leaks. It is important to note that different models of the 3000GT VR4 may have specific requirements for fuel line replacement, so it is recommended to consult model-specific guides or seek advice from experienced mechanics or online forums dedicated to Mitsubishi 3000GTs and Dodge Stealths. Additionally, upgrading to higher-quality fuel lines and filters can further enhance performance and fuel efficiency.

Replacing stock fuel lines with -an lines

Upgrading your fuel lines can be a challenging task, but it is definitely doable with the right tools and knowledge. In this guide, we will walk you through the process of replacing the stock fuel lines with -AN lines on your Mitsubishi 3000GT VR4.

First, it is important to understand the reasoning behind this modification. The stock fuel lines on the 3000GT VR4 are known to be prone to rust and corrosion, which can lead to leaks and other issues. Upgrading to -AN lines can provide better durability, performance, and peace of mind.

To get started, you will need to gather the necessary tools and materials. These include:

• A set of wrenches and sockets
• A drill
• A new fuel pump assembly (if yours is broken or damaged)
• -AN lines and fittings in the appropriate sizes
• Pick-up tube
• Filter
• Any other necessary hardware, such as seals and clamps

Once you have gathered your tools and materials, follow these steps:

• Remove the old fuel lines: Start by removing the old fuel lines from the assembly to the fuel rail. Take note of the routing and positioning of the lines, as you will need to replicate this with the new -AN lines.
• Measure and cut the new -AN lines: Measure the length of the stock fuel lines and cut the new -AN lines to match. It is important to ensure that the new lines are the same length to avoid any issues with fitment.
• Install the new -AN lines: Begin by installing the -AN lines onto the fuel rail, using the appropriate fittings. Work your way back towards the assembly, ensuring that the lines are securely attached and routed correctly.
• Modify the fuel pump assembly: If you are upgrading the fuel pump assembly, follow the instructions provided by the manufacturer. This may involve drilling out holes and installing new fittings and seals.
• Install the external fuel pump: If you are using an external fuel pump, mount it securely and run the new -AN line to the pump. Ensure that the line is clamped securely and that there are no leaks.
• Test the system: Once you have completed the installation, fill the system with fuel and check for any leaks. Start the engine and observe for any issues. Ensure that the fuel pressure is correct and that the engine runs smoothly.

By following these steps, you can successfully upgrade the stock fuel lines on your 3000GT VR4 to -AN lines. This modification can provide improved performance, durability, and reliability. As always, it is important to exercise caution when working on your vehicle and to refer to a professional if you are unsure about any aspect of the installation.

Sizing and sourcing replacement parts

When it comes to sourcing and sizing replacement parts for your Mitsubishi 3000GT VR4 fuel lines, there are a few options and important considerations to keep in mind.

First, you'll need to decide whether to use rubber or braided steel lines. Rubber lines are more susceptible to damage and may not be durable enough, especially for older cars. Braided steel lines with AN fittings are a popular choice for the 3000GT VR4 as they are more durable and can make future removals easier. You can opt for plain black connectors and hoses to avoid the "bling" while still getting the benefits of the stronger material.

If you decide to go with rubber lines, standard rubber fuel line hoses are an option, but you will need to use flare fittings instead of hose clamps.

For the fuel pump, you can choose between a drop-in replacement or an external pump. Drop-in fuel pumps are designed to fit into your existing hanger assembly and can be a direct replacement for your stock pump. External pumps, on the other hand, are mounted outside the fuel tank and can be used in conjunction with an in-tank pump to support higher horsepower.

When it comes to sizing, the fuel line from the tank to the filter is particularly challenging to route, so ensure you have the right length to reach the filter. The STM E85 Fuel Tank to Rail Kit includes lines that are compatible with the 3000GT VR4 and can be a good reference for sizing. Additionally, the fuel line internal to the sending unit may need modification if you are installing a larger pump, as it may be too long and hit the bottom of the tank.

For the fittings, you can use 6-AN or 8-AN fittings, depending on your preference and the size of your fuel rail. The STM E85 Fuel Tank to Rail Kit uses -6AN fittings, while some forum users suggest using -8AN for the feed lines and a -6AN return line.

Finally, don't forget to source any necessary clamps, filters, and adapters to complete the installation.

Removing the battery and tray

To remove the battery and tray from a Mitsubishi 3000GT VR4, follow these steps:

Step 1: Remove the Air Filter Housing

• Unclamp and remove the bolts under the filter element.
• Unclamp the connection between the MAF and the Intake T pipe, then disconnect the MAF harness.
• Rock the filter housing and MAF back and forth while pulling them out.

Step 2: Remove the Intercooler Piping and Y-Pipe

• Unscrew or unbolt all retaining clamps.
• Disconnect the BOV hose on the Intake Manifold.
• Remove the PCV hose between the Intake T pipe and the front cylinder head.
• Remove the hose between the Y-Pipe and the Wastegate solenoid.
• Remove the hose to the BOV.
• Carefully pry on one Turbo Intake pipe and slowly work the Intake T pipe out, being careful not to damage the rubber seal between the Y-Pipe and the Throttle Body.

Step 3: Remove the Battery, Battery Tray, and Washer Fluid Tank

Step 4: Remove the Metal Vacuum Line

Remove the metal vacuum line that runs from the front of the engine bay to the rear.

Step 5: Disconnect the Shift Linkage Brackets and Shift Cables

• Locate and remove the 2 x 12mm bolts attaching the shift linkage brackets to the transmission.
• Pull the cotter pins holding the shift cables to the transmission and disconnect them.

Step 6: Remove the Slave Cylinder

Remove the 2 x 12mm bolts on the rear side of the transmission.

Step 7: Carefully Remove the Black Plastic Piece with a Wiring Harness

• Use extreme caution when taking out this piece.
• If done carefully, you should be able to remove the metal speed sensor pin that is still inside the hole.

Step 8: Remove the Top-Side Bolts Holding the Transmission to the Engine

These are 14mm or 17mm bolts.

Step 9: Remove the Bolt Holding the Transmission Mount

• This is a 17mm bolt with a 17mm nut on the opposite side.
• Use a wrench to hold the nut in place while removing the bolt.

Step 10: Loosen the Lug Nuts on Both Front Wheels

Step 11: Jack Up the Car

Use a jack to raise the car just enough to remove the tires.

Step 12: Remove Both Front Wheels

Step 13: Lower the Car to a Levelled Position

Step 14: Remove the Nut on the Transmission Facing the Inner Fender Well

• Place an oil pan/tray under the transmission.
• The nut is 17mm.

Step 15: Inspect the Transmission Plug for Excessive Metal While the Fluid Drains

Once the fluid is dripping slowly, clean any metal off the plug and put it back into the transmission.

Step 16: Jack Up the Car and Place Jack Stands

Jack up the car as high as possible and place jack stands in a secure location.

Step 17: Remove the Driver's Side Inner Fender Well Trim

• Pull the 4 plugs in the passenger's inner fender well.
• Remove the 4 x 14mm bolts to take off the transmission mount.

Step 18: Remove the Transmission Mount Bracket

Remove the 3 x 17mm bolts that hold the transmission mount bracket to the transmission.

Step 19: Remove the Passenger's Side Inner Fender Well Trim

Step 20: Remove the Cotter Pin and Axle Nut

The axle nut is 32mm.

Step 21: Disconnect the Outer Tie Rod End from the Spindle

You will need a 17mm socket and a pickle fork for this step.

Step 22: Remove the Hub

You can remove the hub from either the ball joint or the strut.

Step 23: Remove the Front Lower Plastic Garnish (Undercover)

This is held in place with a series of 10mm and 12mm bolts.

Step 24: Begin Removing the Downpipe

• There are 2 x 19mm nuts in the front, 2 in the center (rear bank), and two attaching it to the CAT.
• Inspect the gaskets and replace them if necessary.
• If working on a 1996 or later model, remove the O2 sensors in the downpipe.

At this point, you should have successfully removed the battery and tray from your Mitsubishi 3000GT VR4.

Disconnecting and reconnecting the fuel pump

To disconnect and reconnect the fuel pump on a 3000GT VR4, follow these steps:

Firstly, locate the fuel pump assembly, which is found inside the fuel tank. This will involve jacking up the car and removing the fuel tank. Be extremely cautious when working with fuel, ensuring the area is well-ventilated and taking appropriate fire safety precautions. Drain the fuel tank before proceeding.

Once the fuel tank is accessible, you can begin the process of disconnecting the fuel pump. Carefully detach the fuel lines and electrical connectors from the fuel pump assembly. This will involve loosening clamps and disconnecting hoses, as well as unplugging wiring harnesses. Take note of the routing and orientation of the fuel lines and electrical connections for reassembly.

At this point, you should be able to remove the fuel pump assembly from the fuel tank. This may require some wiggling and manipulation to free it from the tank. Be careful not to damage any surrounding components or the fuel tank itself.

To reconnect the fuel pump, simply follow these steps in reverse. Reattach the fuel lines and electrical connectors, ensuring that all connections are secure and properly sealed. Reinstall the fuel tank and lower the vehicle.

It is important to note that working on fuel systems can be dangerous and should only be attempted by those with the appropriate knowledge, skills, and equipment. Always refer to a qualified mechanic or repair manual for specific instructions and safety precautions when working on fuel-related components.

Removing and installing the fuel filter

The fuel filter on a 3000GT/Stealth is located underneath the battery and battery tray and looks similar in size and shape to an oil filter. To remove and install a new fuel filter, follow the steps outlined below.

Removing the Fuel Filter

• Disconnect the negative and positive terminals from the battery posts, always remembering to disconnect the negative terminal first.
• Remove the battery tie-down bar and carefully lift the battery out of the car.
• Remove the battery tray and washer fluid reservoir by unscrewing the four 12mm bolts at the corners of the battery tray.
• Optionally, remove the battery tray bracket and intake pipe for more workspace.
• Disconnect the lower fuel pipe connection. Place shop towels around the filter to catch any leaking gasoline and use safety goggles for protection.
• Remove the upper fuel pipe connection.
• Remove the two 12mm bolts holding the fuel filter bracket to the firewall.
• Disassemble the fuel filter bracket and set aside the bolts, metal sleeves, and rubber spacers for reuse when installing the new fuel filter.

Installing the New Fuel Filter

• Assemble the new fuel filter and bracket using the parts from the previous bracket.
• Bolt the new fuel filter to the firewall using the two 12mm bolts.
• Connect the upper fuel pipe fitting by threading the banjo bolt through the fuel line fitting and into the new fuel filter. Ensure the metal gaskets are placed on both sides of the fuel line fitting.
• Attach the lower fuel pipe connection.
• Reinstall the intake pipe, battery tray bracket, battery tray, washer fluid reservoir, and battery, following the reverse of the removal process.
• Reconnect the battery terminal connections and battery tie-down bar, ensuring the positive terminal is connected first.
• Clean up any gasoline that may have leaked during the process.
• Start the car and check for fuel leaks. Ensure the fuel system maintains about 30 psi of pressure when idling.

Frequently asked questions