Replacing Porsche 911 Fuel Pumps: Bosch Upgrade Guide

If you're experiencing issues with your Porsche 911's fuel pump, you may need to replace it. This is a step-by-step guide on how to replace the fuel pump on a Porsche 911 with a Bosch pump.

Tools and Materials Required:

- Floor jack

- Jack stands

- Wheel chocks

- Safety glasses

- 17mm socket

- Ratchet

- 8mm Allen head socket

- 19mm socket

- 15mm open-end wrench

- Flathead screwdriver

- Two wood blocks for the jack stands

- Fuel pump

- Two copper sealing rings

- Fuel line clamp or very small C-clamp

- Rags (for fuel spill cleanup)

- Fuel pump check valve (including 3 replacement crush washers)

- Electric connection rubber boots (if any are damaged/missing)

Procedure:

- Position the car away from any possible sources of ignition, such as a gas water heater, as you are likely to spill some fuel.

- Place the front of the car up on jack stands. Ensure that the car is near the maximum height of the jack stands to allow room to work under the car.

- Remove the rectangular belly pan between the front wheels. This is usually held in place by 2 bolts and 2 nuts. Be careful as it is heavy.

- Clamp the fuel line gently to prevent fuel spillage.

- Disconnect the fuel pump by detaching the two electrical wires (take note of which is positive and which is negative) and unscrewing the 19mm cap nut that holds the fuel outlet line.

- Loosen the hose clamp holding the fuel pump and remove it.

- Install the new fuel pump, ensuring that you use two new copper sealing rings, one on each side of the banjo fitting.

- Reattach the wiring, making sure that the positive and negative wires are correct.

- Test the new pump and check for any fuel leaks.

Disconnect the negative battery terminal

Disconnecting the negative battery terminal is a crucial step when working on your Porsche 911, especially when dealing with electrical components like the fuel pump. Here are some detailed instructions and important considerations to keep in mind:

Paragraph 1: Safety First

Before you begin, it is imperative to prioritize your safety and that of your vehicle. Disconnecting the negative battery terminal will help prevent any accidental electrical shorts or unexpected activation of components. Ensure you are wearing appropriate safety gear, including gloves and eye protection. Work in a well-ventilated area and avoid any potential sources of ignition, such as a gas water heater, as you will be working near the fuel system.

Paragraph 2: Locating the Negative Terminal

The negative battery terminal is typically marked with a "-" symbol or a black cover. It is usually located on the battery itself, which can be found in the engine bay or, in some models, in the trunk or frunk (front trunk). Refer to your Porsche 911 service manual or consult online forums and resources specific to your model year if you need help locating the battery and its terminals.

Paragraph 3: Disconnecting the Terminal

Once you have located the negative battery terminal, follow these steps to safely disconnect it:

• Loosen the nut or bolt securing the negative battery cable to the terminal using the appropriate size wrench or socket.
• Carefully remove the cable from the terminal, ensuring that it does not touch any metal surfaces or other electrical components.
• If desired, you can cover the terminal with electrical tape or a terminal protector to prevent accidental contact.
• Ensure that the cable is secured away from any moving parts or hot components to avoid damage.

Paragraph 4: Additional Considerations

It is worth noting that some Porsche 911 models may have a negative battery terminal connected to the chassis or body of the vehicle. In these cases, you may find a small door or access panel near the driver's seat or in the trunk/frunk area. Opening this panel will reveal the battery ground connection, which you can then disconnect by removing the acorn nut or bolt holding the cables to the stud.

Paragraph 5: Best Practices

When reconnecting the negative battery terminal, be sure to follow best practices to avoid damage or injury:

• Ensure that all tools and surfaces are clean and free of debris before reconnecting the terminal.
• Double-check that the connection is secure and that the cable is properly seated on the terminal.
• Do not over-tighten the nut or bolt when securing the cable to the terminal, as this can damage the battery post or cable.
• Always refer to your Porsche 911 service manual or seek advice from a qualified mechanic if you are unsure about any aspect of the process.

Remove the belly pan

To remove the belly pan from your Porsche 911, first raise the car on jack stands. You will be working in the space between the front wheels, so it is recommended that the entire car is raised on stands.

Next, locate the rectangular belly pan between the front wheels. Remove the four fasteners holding it in place. On some cars, there are two bolts and two nuts holding the belly pan in place. Be careful as it is a heavy piece of sheet steel and you don't want it falling on you. On some cars, two of the belly pan mounting points are shared with the front sway bar mounts, so you may see the sway bar rotate slightly as you remove the bolts or nuts.

The belly pan is a surprisingly heavy piece of sheet steel, so be careful not to let it fall on you. Once removed, you should see the fuel pump, which is shaped like a small can with hoses connected to both ends.

Clamp the fuel line

To replace the fuel pump on a Porsche 911, you will need to clamp the fuel line to pinch off fuel flow and prevent fuel spillage. Here is a detailed, step-by-step guide on how to do this:

Step 1: Prepare Your Car and Gather Tools

Before you begin, make sure you have the necessary tools and safety equipment. You will need a flat and Phillips screwdriver, a fuel line clamp or a very small C-clamp, and rags for fuel spill cleanup. It is also important to take fire safety precautions when working with the fuel system. Disconnect the negative battery terminal, keep a fire extinguisher nearby, and work in a well-ventilated area away from any sources of heat, spark, or open flame.

Step 2: Raise Your Car on Jack Stands

Use jack stands to raise your car. You will be working in the space between the front wheels, so it is recommended to raise the entire car on stands to give yourself more room to move around.

Step 3: Locate and Remove the Belly Pan

Find the rectangular belly pan between the front wheels and remove the fasteners holding it in place. Be careful as it is heavy, and don't let it fall on you. Once removed, you will see the fuel pump, which is shaped like a small can with hoses connected to both ends.

Step 4: Clamp the Fuel Line

Now, for the critical part, gently clamp the short fuel line between the tank and the fuel pump inlet. Use a very small C-clamp with no sharp edges, and clamp it just hard enough to pinch the line shut without severing it. This will stop the fuel flow and prevent fuel spillage while you work on the fuel pump.

Step 5: Disconnect the Fuel Pump

The fuel pump has two electrical terminals labeled "+" and "-". Take note of which color wire goes with which polarity terminal for later reference. If any of the rubber boots covering the pump terminals are damaged, plan to replace them along with the pump. Disconnect the wires and set them aside.

Loosen the small hose clamp on the pump side of the short fuel line and remove the hose. Verify that the clamp has stopped fuel flow from the tank, as a small amount of fuel may spill.

Step 6: Remove the Banjo Fitting

On the outlet side of the pump, there is a banjo fitting for the pressurized fuel line going to the engine. Loosen the hex cap at the end of the banjo fitting, being careful as the pump may turn with the applied torque. You may need to use penetrating oil and a pair of channel lock pliers or an open-ended wrench to hold the pump steady while turning the hex cap. Once loose, spin off the hex cap and remove the banjo fitting along with the crush washers. More fuel may spill, so have a rag ready.

Step 7: Loosen the Hose Clamp

Loosen the large hose clamp holding the pump body in place. At this point, the pump body can be removed from the car. Remember to save any rubber cushion between the hose clamp and pump body for re-installation later.

By following these steps, you can safely and effectively clamp the fuel line when replacing the fuel pump on a Porsche 911.

Disconnect the fuel pump

Disconnecting the fuel pump is a critical step in replacing the fuel pump of a Porsche 911 with a Bosch alternative. Here is a detailed, step-by-step guide on how to go about it:

Step 1: Safety First

Before starting, it is imperative to take the necessary safety precautions when working with the fuel system. Ensure you disconnect the negative battery terminal and keep a fire extinguisher nearby. It is also crucial to work in a well-ventilated area, free from any sources of ignition, heat, sparks, or open flames.

Step 2: Prepare the Car

Position the car away from any potential sources of ignition, such as a gas water heater. Place the front of the car on jack stands, and ensure it is near the maximum height of the stands to allow for comfortable workspace.

Step 3: Access the Fuel Pump

The fuel pump is located above the splash panel between the front wheels. To access it, remove the splash panel by taking off the two 17mm nuts and the two 8mm Allen-head bolts. Be cautious as the panel is heavier than it appears, so support it when removing the fasteners.

Step 4: Disconnect the Electrical Wires

The fuel pump has two electrical wires connected to it, one positive and one negative. Take note of the correct polarity by observing which wire is connected to the positive and which to the negative terminal. After noting the correct polarity, carefully disconnect the wires.

Step 5: Loosen the Hose Clamps and Cap Nut

Loosen the hose clamp holding the fuel pump in place. Then, unscrew the 19mm cap nut that holds the fuel outlet line in place. You may need to counter-hold this fastener with a 15mm wrench.

Step 6: Remove the Fuel Input Line

Loosen the clamp holding the fuel input line and carefully remove the pump. Work quickly during this step to prevent spilling excessive fuel.

Step 7: Finalize the Disconnection

At this point, the fuel pump should be ready to be removed. However, it is crucial to work carefully and quickly to minimize fuel spillage. Loosen any remaining hose clamps or fasteners holding the pump in place. Once everything is loosened, carefully remove the fuel pump from the vehicle.

Now that the fuel pump has been successfully disconnected, you can proceed to install the new Bosch fuel pump by following the steps in reverse order. Ensure you work efficiently and take the necessary safety precautions throughout the process.

Replace the check valve on the new pump

When replacing the fuel pump on a Porsche 911, it is important to consider the check valve. The check valve is a crucial component of the fuel pump, as it allows fuel to flow in only one direction. This ensures that fuel is delivered efficiently and effectively to the engine.

If you are installing a new Bosch fuel pump, it is important to note that these pumps come with a built-in check valve. This means that you do not need to transfer the check valve from your old pump. Simply install the new Bosch pump as per the manufacturer's instructions, ensuring that the check valve is properly aligned and secured.

However, if you prefer to use the check valve from your old pump, you can do so by carefully removing it and cleaning it before installing it onto the new pump. This may be a preferable option if you are experienced in fuel pump maintenance and want to ensure the continued performance of your Porsche 911.

It is important to note that using two check valves in the fuel pump system is not recommended, as it can affect fuel pressure. Therefore, it is best to either use the built-in check valve in the new Bosch pump or transfer the old check valve, but not use both in conjunction.

When working with fuel pumps and check valves, it is always important to prioritise safety. Ensure that you are wearing appropriate protective gear, including gloves and eye protection, and that you are working in a well-ventilated area to avoid inhaling fumes. Additionally, have a fire extinguisher nearby in case of any accidents or spills.

Frequently asked questions